Lead In Tap Water
CDC Public Health Communications Need Improvement Gao ID: GAO-11-279 March 14, 2011In February 2004, the Centers for Disease Control and Prevention (CDC) was asked to assess the effects of elevated lead levels in tap water on Washington, D.C., residents. In April 2004, CDC published the results. However, an inaccurate statement and incomplete descriptions of the limitations of the analyses resulted in confusion about CDC's intended message. GAO was asked to examine (1) CDC's actions to clarify its published results and communicate current knowledge about the contribution of lead in tap water to elevated blood lead levels (BLL) in children and (2) CDC's changes to its procedures to improve the clarity of the information in its public health communications. GAO reviewed CDC communication policies and procedures and interviewed CDC officials.
CDC officials told GAO that although the agency does not have a policy to monitor the use of or clarify information in public health publications, the agency took actions to address confusion it created related to the 2004 Morbidity and Mortality Weekly Report (MMWR) article about elevated lead levels in Washington, D.C., tap water. For example, in 2008, CDC officials contacted District of Columbia Water and Sewer Authority officials requesting corrections to a statement in a fact sheet published by the water authority that incorrectly characterized information from the 2004 MMWR article. In addition, CDC also published articles in the 2010 MMWR intended to clarify the confusion, such as a June 25, 2010, article that discussed limitations about how information in the 2004 article could be used. While CDC took these actions, among others, to clarify confusion about the effect of elevated lead levels in District tap water, as of January 2011, CDC had no plans to publish an overview of the current knowledge about the contribution of elevated lead levels in tap water to BLLs in children, as suggested by a CDC internal incident analysis of issues surrounding the 2004 MMWR article. CDC officials told GAO they had begun an initiative and revised procedures designed to help ensure the accessibility and clarity of CDC public health communications, both agencywide and in the National Center for Environmental Health, the center responsible for lead poisoning prevention programs. For example, under the new initiative, CDC will revise existing procedures to help ensure that information that CDC publishes, such as guidelines and recommendations, is easily accessible by a common portal on CDC's Web site. While the initiative and revised procedures focus on making CDC information more accessible and on preventing errors or unclear statements in CDC communications, they do not include actions to address confusion that may arise after information is published, such as occurred with the 2004 MMWR article. Without agency procedures specifically addressing how and when to take action about confusion after publication, CDC runs the risk of inconsistent responses across the agency when its published information is not interpreted as CDC intended. CDC's mission to promote the nation's public health relies on its credibility in presenting accurate, reliable, and timely information. Communicating the agency's current knowledge about the health effects of lead levels in tap water and developing procedures that allow it to address confusion in a timely, consistent manner could improve the public's understanding of the effect of lead in water and help CDC mitigate the risk of confusion in other situations and protect its credibility. GAO is making two recommendations to CDC: (1) publish an article providing a comprehensive overview of tap water as a source of lead exposure and communicating the potential health effects on children and (2) develop procedures to address any confusion after information is published. CDC generally concurred with GAO's recommendations. For the second recommendation, while CDC described procedures it is developing, the agency did not explicitly address all components of the recommendation.
RecommendationsOur recommendations from this work are listed below with a Contact for more information. Status will change from "In process" to "Open," "Closed - implemented," or "Closed - not implemented" based on our follow up work.
Director: Cynthia A. Bascetta Team: Government Accountability Office: Health Care Phone: (202) 512-7207GAO-11-279, Lead In Tap Water: CDC Public Health Communications Need Improvement
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United States Government Accountability Office:
GAO:
Report to the Ranking Member, Subcommittee on Energy and Environment,
Committee on Science, Space, and Technology, House of Representatives:
March 2011:
Lead in Tap Water:
CDC Public Health Communications Need Improvement:
GAO-11-279:
GAO Highlights:
Highlights of GAO-11-279, a report to the Ranking Member, Subcommittee
on Energy and Environment, Committee on Science, Space, and
Technology, House of Representatives.
Why GAO Did This Study:
In February 2004, the Centers for Disease Control and Prevention (CDC)
was asked to assess the effects of elevated lead levels in tap water
on Washington, D.C., residents. In April 2004, CDC published the
results. However, an inaccurate statement and incomplete descriptions
of the limitations of the analyses resulted in confusion about CDC‘s
intended message. GAO was asked to examine (1) CDC‘s actions to
clarify its published results and communicate current knowledge about
the contribution of lead in tap water to elevated blood lead levels
(BLL) in children and (2) CDC‘s changes to its procedures to improve
the clarity of the information in its public health communications.
GAO reviewed CDC communication policies and procedures and interviewed
CDC officials.
What GAO Found:
CDC officials told GAO that although the agency does not have a policy
to monitor the use of or clarify information in public health
publications, the agency took actions to address confusion it created
related to the 2004 Morbidity and Mortality Weekly Report (MMWR)
article about elevated lead levels in Washington, D.C., tap water. For
example, in 2008, CDC officials contacted District of Columbia Water
and Sewer Authority officials requesting corrections to a statement in
a fact sheet published by the water authority that incorrectly
characterized information from the 2004 MMWR article. In addition, CDC
also published articles in the 2010 MMWR intended to clarify the
confusion, such as a June 25, 2010, article that discussed limitations
about how information in the 2004 article could be used. While CDC
took these actions, among others, to clarify confusion about the
effect of elevated lead levels in District tap water, as of January
2011, CDC had no plans to publish an overview of the current knowledge
about the contribution of elevated lead levels in tap water to BLLs in
children, as suggested by a CDC internal incident analysis of issues
surrounding the 2004 MMWR article.
CDC officials told GAO they had begun an initiative and revised
procedures designed to help ensure the accessibility and clarity of
CDC public health communications, both agencywide and in the National
Center for Environmental Health, the center responsible for lead
poisoning prevention programs. For example, under the new initiative,
CDC will revise existing procedures to help ensure that information
that CDC publishes, such as guidelines and recommendations, is easily
accessible by a common portal on CDC‘s Web site. While the initiative
and revised procedures focus on making CDC information more accessible
and on preventing errors or unclear statements in CDC communications,
they do not include actions to address confusion that may arise after
information is published, such as occurred with the 2004 MMWR article.
Without agency procedures specifically addressing how and when to take
action about confusion after publication, CDC runs the risk of
inconsistent responses across the agency when its published
information is not interpreted as CDC intended.
CDC‘s mission to promote the nation‘s public health relies on its
credibility in presenting accurate, reliable, and timely information.
Communicating the agency‘s current knowledge about the health effects
of lead levels in tap water and developing procedures that allow it to
address confusion in a timely, consistent manner could improve the
public‘s understanding of the effect of lead in water and help CDC
mitigate the risk of confusion in other situations and protect its
credibility.
What GAO Recommends:
GAO is making two recommendations to CDC: (1) publish an article
providing a comprehensive overview of tap water as a source of lead
exposure and communicating the potential health effects on children
and (2) develop procedures to address any confusion after information
is published. CDC generally concurred with GAO‘s recommendations. For
the second recommendation, while CDC described procedures it is
developing, the agency did not explicitly address all components of
the recommendation.
View [hyperlink, http://www.gao.gov/products/GAO-11-279] or key
components. For more information, contact Cynthia A. Bascetta at (202)
512-7114 or bascettac@gao.gov.
[End of section]
Contents:
Letter:
Background:
CDC Has Issued Statements to Address Confusion It Created Related to
the 2004 MMWR Article, but Has Not Published an Overview of the
Effects of Lead in Tap Water on BLLs in Children:
CDC Has Begun an Initiative and Revised Procedures to Help Ensure That
CDC Information Is Accessible and Clear, but These Procedures Do Not
Address Confusion after Publication:
Conclusions:
Recommendations for Executive Action:
Agency Comments:
Appendix I: 2004 Morbidity and Mortality Weekly Report Article about
Blood Lead Levels of District Residents:
Appendix II: 2010 Letter Clarifying Information about the 2004
Morbidity and Mortality Weekly Report Article:
Appendix III: May 21, 2010, Notice Clarifying Information about the
2004 Morbidity and Mortality Weekly Report Article:
Appendix IV: June 25, 2010, Notice Clarifying Information about the
2004 Morbidity and Mortality Weekly Report Article:
Appendix V: Comments from the Centers for Disease Control and
Prevention:
Appendix VI: GAO Contact and Staff Acknowledgments:
Abbreviations:
BLL: blood lead level:
CDC: Centers for Disease Control and Prevention:
CLPPP: Childhood Lead Poisoning Prevention Program:
CMS: Centers for Medicare & Medicaid Services:
DCDOH: District of Columbia Department of Health:
EPA: Environmental Protection Agency:
HHS: Department of Health and Human Services:
MMWR: Morbidity and Mortality Weekly Report:
NCEH: National Center for Environmental Health:
NHANES: National Health and Nutrition Examination Survey:
pbb: parts per billion:
µg/dL: micrograms per deciliter:
[End of section]
United States Government Accountability Office:
Washington, DC 20548:
March 14, 2011:
The Honorable Brad Miller:
Ranking Member:
Subcommittee on Energy and Environment:
Committee on Science, Space, and Technology:
House of Representatives:
Dear Mr. Miller:
In February 2004, the District of Columbia Department of Health
(DCDOH) requested assistance from the Centers for Disease Control and
Prevention (CDC) to assess the effects of elevated lead levels in the
city's residential tap water on the city's residents.[Footnote 1]
Elevated levels of lead in tap water can result in elevated blood lead
levels (BLL), which can cause adverse health effects in adults and
children.[Footnote 2] CDC, an agency in the Department of Health and
Human Services (HHS), is responsible for developing lead poisoning
prevention programs and policies, and collaborating with federal and
state partners, health departments, and health care providers to
prevent lead poisoning.[Footnote 3] CDC assists state and local
partners in developing laboratory-based surveillance systems for BLLs
among children and assists states in the analysis and dissemination of
lead surveillance data. These activities help contribute to CDC's
efforts in support of HHS's Healthy People 2020 goal of eliminating
elevated BLLs in children.[Footnote 4]
In response to DCDOH's request, CDC worked with individuals from DCDOH
and the U.S. Public Health Service[Footnote 5] to investigate the
effect of lead in the District of Columbia's[Footnote 6] tap water on
the BLLs of residents. On April 2, 2004, CDC published the preliminary
results in an article in the Morbidity and Mortality Weekly Report
(MMWR), the agency's primary vehicle for disseminating public health
information.[Footnote 7] MMWR is intended to provide information that
is timely, reliable, and accurate. However, according to CDC
officials, the article inaccurately stated that no children had BLLs
over CDC's established level of concern, when in fact some children's
BLLs exceeded that level.[Footnote 8] Specifically, despite stating
that "no safe BLL has been identified"[Footnote 9] for children, the
article indicated that although lead in tap water contributed to a
small increase in BLLs in the District, no children were identified
with BLLs above CDC's established level of concern, even in homes with
water lead levels that were greatly in excess of Environmental
Protection Agency (EPA) standards.[Footnote 10] Additionally, CDC
officials have stated that the MMWR article did not fully describe
limitations on how the results should be interpreted and used. In a
June 2010 article in a District newspaper, CDC's Director said that
CDC communicated scientific results poorly in the 2004 MMWR article
and that as a result the article "may have led some people to
improperly minimize concerns about lead exposure and conclude that
lead in the water had never been a problem." Examples of confusion
regarding the seriousness of the health risks include a news report in
which a District official was quoted as saying that CDC's view was
that residents' health had not been affected by elevated water lead
levels in the District, and a news report from another city, which
cited the article to downplay the seriousness of the effect of
elevated water lead levels in the city on the health of children.
CDC's Director stated in a June 2010 letter to the Chairman of the
Subcommittee on Investigations and Oversight, House Committee on
Science and Technology, that the agency planned to make improvements
to agency procedures to enhance the accuracy and clarity of CDC
information.
You asked us to examine CDC's efforts to address confusion and clarify
information in the 2004 MMWR article related to elevated BLLs in
District residents. In this report, we examine (1) the actions CDC has
taken to clarify the information in the agency's 2004 MMWR article
about BLLs of District residents and to communicate current knowledge
about the contribution of lead in tap water to elevated BLLs in
children and (2) changes CDC has made to its procedures in an effort
to ensure the clarity of the information in its public health
communications.
To describe the actions CDC has taken to clarify the information in
the agency's 2004 MMWR article about BLLs of District residents and to
communicate current knowledge about the contribution of lead in tap
water to elevated BLLs in children, we reviewed CDC documents and
publications related to the elevated lead levels in the District's tap
water, including the 2004 MMWR article and a 2010 MMWR article
describing the limitations of the 2004 article; CDC correspondence
with local agencies, such as the District of Columbia Water and Sewer
Authority (Water and Sewer Authority); CDC's February 2010 internal
incident analysis--requested by CDC's Office of the Director--of its
response to issues surrounding elevated water lead levels in the
District; media reports that refer to information in the 2004 MMWR
article; and congressional reports and testimony. We also reviewed CDC
reports and other documents describing subsequent investigations
related to or referenced in the 2004 MMWR article, such as EPA's
report on the potential causes of elevated lead levels in District tap
water. We interviewed CDC officials, including officials from the
National Center for Environmental Health (NCEH), about their actions
to clarify any confusion related to information in the 2004 MMWR
article.[Footnote 11] We also interviewed CDC officials about any
ongoing work CDC has conducted since publishing its preliminary
findings in the 2004 MMWR article, and any additional work planned for
the future to clarify information in the 2004 MMWR article. We
interviewed officials from the Office of the Director and other senior
management officials to determine their responses to the internal
incident analysis and any related directives from the Office of the
Director to NCEH or other CDC entities, and we examined the status of
agency activities to respond to any related directives. We also
attended a meeting of the Advisory Committee on Childhood Lead
Poisoning Prevention--a federal advisory committee to CDC--in November
2010 to obtain any updates to the findings presented in 2004 or other
relevant information.
To describe changes CDC has made to its procedures in an effort to
ensure the clarity of the information in its public health
communications, we reviewed CDC communication policies and procedures
and interviewed CDC officials about any initiatives the agency is
developing or has implemented since 2004 to help ensure that the
messages presented in its public health communications are clear and
accurate.
We conducted this performance audit from August 2010 through February
2011 in accordance with generally accepted government auditing
standards. Those standards require that we plan and perform the audit
to obtain sufficient, appropriate evidence to provide a reasonable
basis for our findings and conclusions based on our audit objectives.
We believe that the evidence obtained provides a reasonable basis for
our findings and conclusions based on our audit objectives.
Background:
The MMWR series is one of three scientific publications published by
CDC and is regarded as CDC's flagship publication.[Footnote 12] The
publication's primary audience is made up of professionals, including
medical professionals, such as clinicians, and state and local public
health officials, and the publication also reaches CDC's federal
partners, such as EPA and the Centers for Medicare & Medicaid Services
(CMS). In addition to the weekly reports, the MMWR series also
includes MMWR Recommendations and Reports, which contain in-depth
articles that relay policy statements for prevention and treatment on
all areas in CDC's scope of responsibility, such as recommendations
from CDC advisory committees. CDC can also issue articles that it
calls Dispatches to allow for immediate publication of urgent public
health information. The Dispatches are generally subsequently
published in the MMWR. The April 2, 2004, MMWR weekly report included
an article on the BLLs of District residents that was first published
as a Dispatch on March 30, 2004.
Exposure to Lead in the Environment:
Lead is a dangerous contaminant commonly found in the environment that
can affect almost every organ and system in the body. The main target
for lead toxicity is the nervous system. In addition to causing
behavior problems and learning disabilities in young children,
elevated BLLs can cause such effects as damage to the brain and
kidneys. In pregnant women, elevated BLLs may cause miscarriage.
Drinking contaminated tap water is one way humans may be exposed to
lead.[Footnote 13] While measures taken during the past two decades
have greatly reduced exposures to lead in tap water, lead still can be
found in some metal water fixtures, interior water pipes, or pipes
connecting a house to the main water pipe in the street. Lead in tap
water usually comes from the corrosion of older fixtures; lead service
lines, including lead service pipes; or the solder that connects pipes.
Federal law requires that blood lead screening tests be made available
to all children enrolled in Medicaid.[Footnote 14] CMS's State
Medicaid Manual requires that these screenings be performed at ages 12
and 24 months and that all children aged 36 to 72 months who have not
previously been screened also receive a blood lead test. The American
Academy of Pediatrics agrees with these requirements for screening and
has also stated that efforts must continue to test children who are at
high risk for lead exposure. Beginning in 1995, elevated BLLs--the
first noninfectious condition--were designated as a nationally
notifiable condition reportable to CDC. The District (along with 36
states and the city of New York) has reported elevated BLLs of 10
micrograms per deciliter (g/dL) of blood or higher for children to
CDC. The District has reported this BLL information to CDC since 1997.
The District's Childhood Lead Poisoning Screening and Reporting Act of
2002 requires that each health care provider or facility in the
District perform a blood test for lead poisoning as part of a well-
child care visit for each child that they serve who is under the age
of six and resides in the District. The test must occur between ages 6
months and 14 months, and a second test must occur between ages 22
months and 26 months. Both tests must be performed unless parental
consent is withheld or an identical test has already been performed
within the previous 12 months.[Footnote 15] If a child's age exceeds
26 months and a blood lead screening has not been performed, the child
must be screened twice before age 6.[Footnote 16] The District also
requires health care providers or facilities to report the results of
blood tests for lead poisoning on every child under age 6 who resides
in the District to the child's parents.[Footnote 17]
CDC's Roles and Responsibilities regarding Lead:
As the nation's public health agency, CDC has set levels of concern--
the BLL that should prompt public health actions--for lead exposure
since the 1960s.[Footnote 18] In 1991, CDC set the level of concern at
10 g/dL of blood for:
children aged 6 months to 15 years and 25 g/dL for adults. [Footnote
19]However, CDC has also recognized that a BLL of 10 g/dL does not
define a threshold for the harmful effects of lead--in other words, no
safe blood lead level has been identified for children.
The Lead Contamination Control Act of 1988 authorized CDC to initiate
programs to eliminate childhood lead poisoning in the United States.
[Footnote 20] As a result of this act, the CDC Childhood Lead
Poisoning Prevention Program (CLPPP) was created. One of the program's
primary responsibilities is to educate the public and health care
providers about childhood lead poisoning. CDC's CLPPP also provides
funding to state and local health departments to determine the extent
of childhood lead poisoning by screening children for elevated BLLs.
Since the inception of CDC's lead program, nearly 60 state and local
jurisdictions have received funding for their state and local CLPPPs.
CDC's efforts contribute to the Healthy People 2020 initiative, which
includes an objective to eliminate elevated BLLs in children. As of
2007 to 2008, the latest years for which data were available,
approximately 1.2 percent of children aged 1 to 5 years nationwide had
BLLs exceeding 10 µg/dL.[Footnote 21]
In addition, the Advisory Committee on Childhood Lead Poisoning
Prevention advises and guides CDC regarding new scientific knowledge
and technical developments and their practical implications for
childhood lead poisoning prevention efforts.[Footnote 22] In November
2010, the advisory committee initiated a work group to recommend new
approaches, terminology, and strategies for defining elevated BLLs
among children.
EPA's Roles and Responsibilities regarding Lead:
Under the Safe Drinking Water Act, EPA is responsible for regulating
contaminants that may pose a public health risk and that are likely to
be present in public water supplies, including lead.[Footnote 23]
EPA's Lead and Copper Rule established a 15 parts per billion (ppb)
lead action level as a regulatory standard for water utilities in an
effort to prevent and mitigate the adverse health consequences
resulting from elevated lead levels in drinking water.[Footnote 24]
Water systems must sample tap water at locations that are at high risk
of lead contamination, generally because they are served by lead
service lines or are likely to contain lead solder in the household
plumbing. If more than 10 percent of the samples at residences contain
lead levels over 15 ppb, the water systems must take action to lower
these levels, such as replacing lead service lines in the distribution
system or treating water to reduce its corrosion of the service lines,
and notify EPA and residents.
The District's Elevated Water Lead Levels Prior to CDC's Involvement:
The District's Water and Sewer Authority owns and operates a system
that delivers water--produced by the U.S. Army Corps of Engineers
Washington Aqueduct--to customers in the District. In 2000, the
Washington Aqueduct began to use chloramine instead of chlorine in its
disinfection process.[Footnote 25] This change likely contributed to
elevated water lead levels.
By late 2001, the Water and Sewer Authority became aware that the
levels of lead in the District's tap water were above EPA's limit of
15 ppb, and it notified EPA of that fact in August 2002. Beginning in
2002, the Water and Sewer Authority notified its customers of the
elevated water lead levels by issuing notices, distributing
educational brochures, and holding public meetings. In the fall of
2003, the Water and Sewer Authority requested assistance from DCDOH in
responding to District residents' inquiries about the health effects
of the elevated water lead levels. District residents, including
infants and children, would have been exposed to elevated levels of
lead in tap water during this period if they used unfiltered water for
drinking, cooking, or preparing infant formula or juice.
Information in the 2004 MMWR Article:
Staff from NCEH, along with individuals from DCDOH and the U.S. Public
Health Service, contributed to CDC's investigation on the effect of
lead in the District's tap water on the BLLs of residents, which was
presented in the April 2, 2004, MMWR article. The 2004 MMWR article
reported the results of two analyses from CDC's investigation, which
was conducted in February and March 2004. (See appendix I for a copy
of the 2004 MMWR article.) The first analysis was conducted to
identify trends in BLLs in District residents before and after the
changes in the water disinfection process. The second analysis was
conducted to determine whether residents in homes with the highest
water lead levels (300 ppb or greater) had BLLs at or above CDC's
level of concern of 10 g/dL.
The summary statement of the 2004 MMWR article's findings noted that
the elevated water lead levels might have contributed to a small
increase in BLLs among District residents. The article's Editorial
Note section opened with a sentence that incorrectly stated the
results of the first analysis. The sentence read, "The findings in
this report indicate that although lead in tap water contributed to a
small increase in BLLs in D.C., no children were identified with BLLs
10 ug/dL, even in homes with the highest water lead levels." The
statement that "no children were identified with BLLs 10 g/dL" was
incorrect, relative to the first analysis. Since the 2004 MMWR article
was published, CDC officials have said that in its first analysis some
children were identified with BLLs 10 g/dL, which is CDC's level of
concern for children. The last part of the statement indicating that
none of the children in homes with the highest water lead levels had
BLLs > 10 g/dL was correct, in that none of the 30 children in the
second analysis had BLLs that reached CDC's level of concern,
according to CDC officials. While the 2004 MMWR article discussed some
limitations to its findings, it did not discuss other limitations that
addressed how information in the 2004 MMWR article could be used. For
example,[Footnote 26] it did not state that the article should not be
used to make conclusions about the contribution of lead in tap water
to BLLs in the District.
Confusion about the 2004 MMWR Article's Findings:
The statement in the 2004 MMWR article that incorrectly links the
results of the two analyses in the same editorial note and the
incomplete description of the limitations to the article's findings
have resulted in this information being interpreted in the press and
by others in ways other than as CDC intended. For example:
* In a May 2004 hearing before the House Committee on Government
Reform, some business and environmental advocates included references
to the 2004 MMWR article to (1) support their assertion that the
elevated water lead levels did not warrant a panicked reaction in the
District or (2) draw conclusions about the relationship between BLLs
and water lead levels in the District, which CDC later stated were
inappropriate.
* In July 2004, a newspaper article from a major metropolitan city
that was experiencing elevated lead levels in schools' tap water
included information about the 2004 MMWR article's findings to support
statements that downplayed the seriousness of the effect of elevated
water lead levels in the city on the health of children.
* In a February 2008 fact sheet, the Water and Sewer Authority
referenced the 2004 MMWR article and included statements that gave the
impression that the health of District children had not been affected
by elevated lead levels in the District's tap water.
* In February 2009, the General Manager of the Water and Sewer
Authority was quoted in a newspaper article as saying that CDC's view
was that residents' health had not been affected by elevated water
lead levels in the District.
* As recently as December 2010, news articles in the District reported
that in the 2004 MMWR article CDC indicated that it found no evidence
of measurable or significant harm to the public health of District
children from elevated lead levels in tap water.
In addition, CDC officials have recognized that the 2004 MMWR article
may have led people to conclude that there was no danger to children
from the elevated water lead levels.
CDC Has Issued Statements to Address Confusion It Created Related to
the 2004 MMWR Article, but Has Not Published an Overview of the
Effects of Lead in Tap Water on BLLs in Children:
Although CDC does not have a policy to monitor the use of or clarify
information in public health publications, such as the information in
the 2004 MMWR article, the agency issued statements to address
confusion it created related to elevated lead levels in the District's
tap water. However, as of January 2011, the agency had no plans to
publish an overview of the current knowledge about the effects of lead
in tap water on BLLs in children. Specifically, CDC has not published
an overview of what is known and not known about tap water as a source
of lead exposure and the potential health effects on children, as
suggested by the CDC internal incident analysis.
CDC Has Issued Statements and Taken Other Actions to Address Confusion
It Created Related to the 2004 MMWR Article:
CDC officials told us that although the agency does not have a policy
to monitor the use or clarify interpretations of information in public
health publications, such as the 2004 MMWR article, the agency has
issued statements to address confusion it created related to the 2004
MMWR article. Specifically, agency officials said they have taken some
actions since 2006 to address confusion CDC created about the 2004
MMWR article when they became aware of specific instances of
confusion. For example:
* In July 2006, a CDC official was interviewed for an article
published in an environmental science journal and provided information
to address public statements attributed to a health advisor for the
District's Water and Sewer Authority that incorrectly characterized
information from the 2004 MMWR article. The CDC official stated that
the 2004 MMWR article did not say that drinking water with very high
water lead levels, such as those found in some District homes, was
safe.
* In February 2008, a CDC official corresponded with the District's
Water and Sewer Authority officials about a statement in a February
2008 fact sheet published by the water authority that incorrectly
characterized information in the 2004 MMWR article. Specifically, the
CDC official noted that the fact sheet misstated the conclusions of
the 2004 MMWR article and gave the impression that the health of
District residents had not been affected by elevated lead levels in
the tap water. The CDC official requested that the statement be
corrected. In April 2009, the Director of NCEH sent a letter to the
General Manager of the water authority noting that this correction and
others had not been made and once again asked that statements
published in the fact sheet be corrected to accurately reflect the
conclusions in the 2004 MMWR article: that because no threshold for
adverse health effects in young children had been demonstrated, public
health interventions should focus on eliminating all lead exposures in
children.
* In 2009, the Chief of the Healthy Homes and Lead Poisoning
Prevention Branch contacted officials responsible for drinking water
safety in Seattle and New York City to discuss reports that officials
were quoted in newspaper articles in those localities and had
mischaracterized information in the 2004 MMWR article to downplay the
effect of lead in water and that these cities had relaxed their
drinking water standards based on the 2004 MMWR article. The CDC
official said that she contacted the officials to clarify the 2004
MMWR article's message about the public health effect of elevated lead
levels in the District's tap water and was assured that they had not
used the 2004 MMWR article to make any changes in their drinking water
standards.
More recently, CDC sent a letter to state and local CLPPP managers,
published articles in the MMWR, and contacted District newspaper
officials to address confusion it created related to the 2004 MMWR
article. Specifically:
* In May 2010, CDC provided clarifying information in a letter to
state and local CLPPP managers. (See appendix II for a copy of the May
2010 letter.) The Chief of the Healthy Homes and Lead Poisoning
Prevention Branch sent a letter dated May 20, 2010, to state and local
CLPPP managers saying that the first sentence in the Editorial Note
section in the 2004 MMWR article incorrectly stated the results of the
first analysis, as some children were identified with BLLs above 10
g/dL. Additionally, the letter presented results of a 2009 analysis
that included new BLL data that had not been available to CDC in 2004.
The letter further stated that the results of this new analysis
confirmed the original finding, which CDC stated was that lead in
water was associated with an increase in BLLs. The letter also
restated CDC's intended message presented in the 2004 MMWR article--
that no safe blood lead level had been identified and all sources of
lead exposure should be controlled or eliminated. The letter was also
posted on the CDC Web site.
* On May 21, 2010, CDC issued a Notice to Readers in the MMWR
providing the same information about the 2009 analysis and addressing
the confusion CDC created related to the 2004 MMWR article.[Footnote
27] (See appendix III for a copy of the May 21, 2010, MMWR Notice to
Readers.)
* On June 25, 2010, CDC issued a Notice to Readers in the MMWR noting
the limitations of the results of the second analysis in the 2004 MMWR
article.[Footnote 28] (See appendix IV for a copy of the June 25,
2010, MMWR Notice to Readers.) The Notice to Readers stated that the
results of the second analysis should not be used to (1) make
conclusions about the contribution of lead in tap water to BLLs in the
District, (2) predict what might occur in other situations where lead
levels in tap water are high, or (3) determine safe levels of lead in
tap water.
* In December 2010, CDC officials said that they contacted a District
newspaper when it published news reports that included
misinterpretions of the results of the 2004 MMWR article. CDC
officials said that they contacted the newspaper the same day that the
first news report was published, and for several days thereafter when
additional news reports were published, to request clarifications. CDC
officials told us that they also had submitted a letter to the
newspaper to provide more information to help ensure that the public
correctly understood the 2004 MMWR article's intended message. The
letter was published in December 2010 and stated that CDC's opinion on
the health impact of lead in the District's water supply has not
changed and that a new study reports what the agency has been saying
since 2004--the presence of lead service lines increases the BLLs in
the District's children.[Footnote 29]
CDC Has Not Published an Overview of the Effects of Lead in Tap Water
on BLLs in Children:
Although CDC has taken actions to address confusion specific to the
2004 MMWR article, as of January 2011, CDC had not taken action to
publish an overview of the current knowledge about the contribution of
elevated lead levels in tap water to BLLs in children and the
associated health effects. The 2010 internal incident analysis of
CDC's involvement in and response to issues surrounding elevated water
lead levels in the District noted that because the relative
contribution of tap water to elevated BLLs in children has become more
apparent as exposure to lead paint and leaded gasoline has been
reduced or eliminated, a systematic evaluation of the relative
contribution of tap water to elevated BLLs should be conducted.
[Footnote 30] Specifically, the internal incident analysis suggested
that CDC conduct such an evaluation and publish the information in an
article in the MMWR Recommendations and Reports that would serve as a
position paper covering the issues of lead in municipal water supplies
and summarizing what is known and not known about its contribution to
historic and contemporary BLLs in children. A CDC official said that
as of January 2011, CDC had no plans to conduct such an evaluation and
publish an overview on the effects of lead in water on BLLs in
children in the MMWR Recommendations and Reports. CDC noted that while
the agency does not lack the authority to undertake such an
evaluation, the agency believes that such an evaluation is better
suited to EPA, given EPA's responsibility, regulatory authority, and
expertise. The agency also noted that EPA is currently in the process
of reviewing EPA's regulations for the control of lead and copper in
drinking water.[Footnote 31] CDC noted that the agency could provide
technical assistance to EPA and would consider publishing an article
after the EPA review is complete. However, publishing an article in
the MMWR Recommendations and Reports on the latest findings regarding
the relationship between BLLs and lead in water could be of assistance
to EPA. Moreover, it would allow CDC, in a timely manner, to address
any remaining confusion related to the health effects of lead in water
in a venue targeted to CDC's audience. Because CDC has not published
an overview of the health effects of lead in water in the MMWR
Recommendations and Reports, clinicians and state and local health
officials who look to CDC for comprehensive information on public
health issues may be uncertain about what is known and not known about
the contribution of elevated lead levels in tap water to BLLs in
children.
CDC Has Begun an Initiative and Revised Procedures to Help Ensure That
CDC Information Is Accessible and Clear, but These Procedures Do Not
Address Confusion after Publication:
CDC officials told us they had begun an initiative and revised
procedures to help ensure the accessibility and clarity of CDC public
health communications prior to publication, both agencywide and in
NCEH. Specifically, an official from the Office of the Director told
us that the CDC Office of the Associate Director of Science has begun
an initiative to revise existing procedures to help ensure that
information that CDC publishes, such as guidelines and
recommendations, is easily accessible by a common portal on CDC's Web
site. As of January 2011, CDC officials were still determining what
type of CDC products and communication methods would be included in
the initiative. In addition, CDC officials told us that NCEH, the
center responsible for lead poisoning prevention programs and the 2004
MMWR article, had revised its clearance procedures for certain
products, including those submitted to the MMWR, in an effort to
ensure that the information presented is accurate and clear. CDC
officials said that the revised NCEH clearance procedures are more
rigorous and systematic and include requirements for additional peer
review of some products, as well as review of some products by the
Office of the Director, to help ensure that senior officials are aware
of the products. For example, CDC documents that include major
scientific findings or conclusions representing scientific
breakthroughs or that directly contradict previous science that served
as the basis for public health policy will be elevated to the Office
of the Director for review. The officials said that the agency
believes the initiative and revised procedures will help to mitigate
the risk of other communications being subject to the type of
confusion or misinterpretation surrounding the 2004 MMWR article. As
of January 2011, CDC did not have time frames for completing the
Office of the Director's initiative.
Despite the agency's current actions to strengthen review of CDC
communications prior to publication, CDC officials said that neither
the initiative nor the revised procedures will include actions to
address confusion after publication. For example, if CDC becomes aware
that information is being interpreted incorrectly, the procedures will
not direct CDC staff to reach out to newspapers or other entities that
have published the information to request corrections or
clarifications. The importance of having procedures for this type of
outreach was noted in the internal incident analysis, which stated
that when CDC messages are not on target or are misinterpreted, such
as happened in reaction to the 2004 MMWR article, CDC should respond
in appropriate visible forums to publicly and expeditiously correct
itself or correct those who are interpreting the message. Further,
neither the initiative nor the revised procedures will include any
postpublication review of certain types of communications that are
similar to the 2004 MMWR article, such as those that are published in
an expedited time frame and address urgent or high-profile issues, to
determine whether corrections or clarifications are needed based on
how the communications have been interpreted or used. Because CDC does
not have procedures for addressing confusion after publication, the
agency runs the risk that its staff will provide inconsistent
responses to interpretations of its information that differ from what
CDC intended.
Conclusions:
Although CDC has taken some belated actions to clarify confusion
related to the 2004 MMWR article on BLLs of residents in the District,
the agency does not plan to publish a comprehensive review of the role
of tap water as a source of lead exposure that would communicate what
is known about the contribution of lead in water to elevated BLLs in
children. A goal of the Healthy People 2020 initiative is to eliminate
elevated BLLs in children. Although significant progress has been made
in reducing lead exposure from lead-based paint and leaded gasoline,
CDC has an opportunity to refocus its efforts toward accomplishing
this Healthy People 2020 goal and to make a significant contribution
to scientific literature by clearly describing what is known about the
effect of lead in tap water on BLLs in children.
CDC's credibility as the nation's premier public health agency relies
on presenting accurate, reliable, and timely information to the
public. Information that is inaccurate or unclear in a CDC public
health publication could result in confusion--such as resulted when
some readers understood the 2004 MMWR article to state that elevated
lead levels in tap water were not a concern in the District or in
their area--and could undermine the agency's credibility. The
potential for presenting confusing information may increase when the
agency has to respond quickly, as it did when it published the 2004
MMWR article 6 weeks after the DCDOH requested CDC's assistance. When
CDC presents potentially confusing information and does not respond in
a timely or consistent fashion to clarify confusion following
publication of a public health product, the agency runs the risk that
an incorrect interpretation of the intended message could put the
public at risk of adverse health effects, such as those that result
from elevated water lead levels. CDC can mitigate the risk of such
misinterpretations as well as the resulting risk to its credibility by
developing procedures that allow it to address confusion in a timely,
consistent manner.
Recommendations for Executive Action:
We are recommending that the Director of CDC take two actions, the
first to clarify confusion about the contribution of lead in tap water
to elevated BLLs, and the second to improve the clarity of CDC's
published information on public health issues.
1. Publish an article in an MMWR Recommendations and Reports that
conveys what is known and not known about tap water as a source of
lead exposure and communicates the potential health effects in
children of elevated lead levels in water in consultation with EPA, as
appropriate.
2. Develop procedures to review previously published information and
determine whether additional information should be published to help
ensure the correct understanding of the public health message. The
procedures could include criteria to use when deciding how to respond
in certain situations, such as the event in the District, in which:
* CDC learns of confusion about the public health message and
determines that clarification or additional information should be
published or:
* CDC issues or releases a product in an expedited time frame or based
on uncertain or incomplete information and determines additional
information should be published to clarify the original public health
message, even if there is no evidence of confusion.
Agency Comments:
CDC reviewed a draft of this report and provided written comments,
which are reprinted in appendix V. CDC generally concurred with our
recommendations and submitted general comments on the draft.
CDC agreed with our first recommendation to publish an article in an
MMWR Recommendations and Reports. While CDC previously stated that it
had no plans to publish such an article, it stated in its written
comments that it now plans to publish an article in an MMWR
Recommendations and Reports that will focus on what is known about tap
water as a source of lead exposure and summarize the potential health
effects in children from lead exposures.
Related to our second recommendation to develop procedures to review
previously published information and determine whether additional
information should be published to help ensure the correct
understanding of the public health message, CDC said it planned to
adopt several procedures for taking action when the agency becomes
aware of confusion about its message. CDC's written comments indicated
that these procedures will be effective when approved by the CDC
Director. Specifically, CDC stated that when appropriate, it may take
actions to address significant errors of understanding or perception
resulting from public health information disseminated by the agency.
For example, for errors of understanding or perception in which there
is a persistent, broad, or otherwise significant misinterpretation of
information in a public health product, CDC will present the
scientific conclusions in clear language in several ways, such as a
posting on the CDC Web site or by direct outreach to the news and
electronic media, including via press releases or letters to the
editor. However, within these procedures, CDC did not explicitly
address situations where CDC issues or releases a product in an
expedited time frame or based on uncertain or incomplete information
and determines additional information should be published to clarify
the original public health message, even if there is no evidence of
confusion. It is important that CDC take this additional step in order
to help ensure that the agency can address confusion in a timely
manner and thereby mitigate risk to the public's health or the
agency's credibility.
CDC also provided technical comments, which we incorporated as
appropriate.
As agreed with your office, unless you publicly announce the contents
of this report earlier, we plan no further distribution until 30 days
from the report date. At that time, we will send copies to the
Secretary of Health and Human Services and other interested parties.
The report also will be available at no charge on the GAO Web site at
[hyperlink, http://www.gao.gov].
If you or your staff have any questions about this report, please
contact me at (202) 512-7114 or at bascettac@gao.gov. Contact points
for our Offices of Congressional Relations and Public Affairs may be
found on the last page of this report. Other major contributors to
this report are listed in appendix VI.
Sincerely yours,
Signed by:
Cynthia A. Bascetta:
Managing Director, Health Care:
[End of section]
Appendix I: 2004 Morbidity and Mortality Weekly Report Article about
Blood Lead Levels of District Residents:
[End of section]
On April 2, 2004, the Centers for Disease Control and Prevention (CDC)
published the following article in the Morbidity and Mortality Weekly
Report, which presented results of the investigation on the effect of
lead in the District's tap water on the blood lead levels of
residents. Additionally, in 2010 CDC added the information contained
in the box under the article's title. The article is presented here in
its electronic version, which was accessed from CDC's Web site.
CDC:
MMWR:
Weekly:
April 2, 2004/53:(12); 268-270:
Blood Lead Levels in Residents of Homes with Elevated Lead in Tap
Water - District of Columbia, 2004:
The methods and findings in this April 2004 MMWR report have been the
subject of continuing interest. In two Notices to Readers, published
in the May 21, 2010, and June 25, 2010, issues, CDC has noted
limitations of methods employed and the manner in which findings were
communicated. Readers should be aware of these limitations, as well as
the steps taken to address them.
The two Notices to Readers are as follows:
1. Notice to Readers: Examining the Effect of Previously Missing Blood
Lead Surveillance Data on Results Reported in the MMWR. Available at
[hyperlink, http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5919a4.htm].
2. Notice to Readers: Limitations Inherent to a Cross-Sectional
Assessment of Blood Lead Levels Among Persons Living in Homes with
High Levels of Lead in Drinking Water. Available at [hyperlink,
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5924a6.htm].
CDC authors have published an extended analysis. See: Brown MJ,
Raymond J, Homa D, Kennedy C, Sinks T. Association between children's
blood lead levels, lead service lines, and water disinfection.
Washington DC, 1998-2006. Environ Res 2010. Epub ahead of print.
Available at [hyperlink,
http://www.elsevier.com/wps/find/journaldescription.cws_home/622821/desc
iption].
On March 30, this report was posted as an MMWR Dispatch on the MMWR
website [hyperlink, http://www.cdc.gov/mmwr].
Lead exposure adversely affects intellectual development in young
children and might increase the risk for hypertension in adults (1).
In the District of Columbia (DC), of an estimated 130,000 residences,
approximately 23,000 (18%) have lead service pipes (Daniel Lucey, MD,
DC Department of Health [DCDOH], personal communication, March 24,
2004). The Environmental Protection Agency (EPA) requires water
authorities to test tap water in 10-100 residences annually for lead.
In March 2003, DC Water and Sewer Authority (WASA) expanded its lead-
in-water testing program to homes with lead service pipes extending
from the water main to the house. By late January 2004, results of the
expanded water testing indicated that the majority of homes tested had
water lead levels above EPA's action level of 15 parts per billion
(ppb). On February 16, DCDOH requested CDC assistance to assess health
effects of elevated lead levels in residential tap water. DCDOH also
requested deployment of officers of the United States Public Health
Service (USPHS) to assist in the investigations. This report
summarizes the results of the preliminary investigations, which
indicated that the elevated water lead levels might have contributed
to a small increase in blood lead levels (BLLs). The investigation of
elevated water lead levels is ongoing. In the interim, DCDOH has
recommended that young children and pregnant and breast-feeding women
refrain from drinking unfiltered tap water (2).
CDC's BLL of concern for children, 10 ug/dL, was adopted in 1991 in
response to evidence associating BLLs greater than or equal to 10
ug/dL with adverse health effects (3). Adverse health effects have
been reported recently at BLLs less than 10 ug/dL, particularly in
vulnerable populations (e.g., infants and children) (4,5); no safe BLL
has been identified (6). Longitudinal analysis was conducted to
identify trends in BLLs in DC before and after changes in the water
disinfection process by comparing homes with lead service pipes to
homes without lead service pipes. Both the percentage of BLLs greater
than or equal to 10 ug/dL and those greater than or equal to 5 ug/dL
were examined over time. Cross-sectional analysis of BLLs of residents
in homes with the highest water lead levels was conducted to determine
if residents had BLLs greater than or equal to 10 ug/dL.
Longitudinal Analysis of Childhood Blood Lead Screening Tests:
WASA provided DCDOH and CDC with a list of homes (n = 26,141) with
lead service pipes. During January 1998-December 2003, the DCDOH blood
lead surveillance system recorded 84,929 BLLs. Of these, 43,314 (51%)
tests were venous, and 6,794 (8%) were fingerstick; sample type was
not listed on the remaining tests. All blood tests were used in this
analysis. For each year of testing, these databases were linked by
address. A total of 11,061 BLL laboratory requisition slips listed an
address with a lead service pipe.
During 1998-2000, the percentage of BLLs greater than or equal to 10
ug/dL and greater than or equal to 5 ug/dL decreased substantially,
regardless of the type of service pipe (Figure). During 2000--2003,
the percentage of BLLs greater than or equal to 10 ug/dL in persons
living in homes known to have lead service pipes decreased from 9.8%
to 7.6% (p = 0.008). The percentage of BLLs greater than or equal to 5
ug/dL in persons living in houses without lead service pipes continued
to decrease, from 22.7% to 15.6% (n = 14,152; p300 ppb Lead in Water:
WASA provided the results of lead testing on water samples from 6,170
homes. Of these, 163 (3%) had lead levels >300 ppb in second-draw
water collected after a change in water temperature, indicating that
some of the lead in the water leached from water pipes outside the
home. USPHS officers working in the DCDOH Incident Command structure
contacted residents in the 140 (86%) homes that had telephones and
arranged for visits to draw venous samples for BLLs. The DC Public
Health Laboratory determined BLLs by using graphite furnace atomic
absorption spectrophotometry for 184 persons in 86 households who
consented to having blood drawn. Residents were provided with a water
filter and information about reducing lead exposure. In addition, in
12 of the households contacted, 17 persons had a venous blood test
drawn independently and reported to DCDOH since January 2004. These
test results also were included in this analysis.
Of the 201 residents from 98 homes with water lead levels greater than
300 ppb tested for BLLs, all had BLLs below CDC's levels of concern
(10 ug/dL for children aged 6 months--15 years and 25 ug/dL for
adults) (Table). Of the 201 residents, a total of 153 (76%) reported
drinking tap water, and 52 households (53%) reported using a water
filter. On February 26, 2004, DCDOH sent a letter to all DC homes with
lead service pipes, recommending that young children and pregnant and
breast-feeding women refrain from drinking unfiltered tap water (2).
Reported by: L Stokes, PhD, NC Onwuche, P Thomas, PhD, JO Davies-Cole,
PhD, T Calhoun, MD, AC Glymph, MPH, ME Knuckles, PhD, D Lucey, MD,
District of Columbia Dept of Health. T Cote, MD, G Audain-Norwood, MA,
M Britt, PhD, ML Lowe, MCRP, MA Malek, MD, A Szeto, MPH, RL Tan, DVM,
C Yu, M Eberhart, MD, US Public Health Svc. MJ Brown, ScD, C Blanton,
MS, GB Curtis, DM Homa, PhD, Div of Emergency and Environmental Health
Svcs, National Center for Environmental Health, CDC.
Editorial Note:
The findings in this report indicate that although lead in tap water
contributed to a small increase in BLLs in DC, no children were
identified with BLLs greater than or equal to 10 ug/dL, even in homes
with the highest water lead levels. In addition, the longitudinal
surveillance data indicate a continued decline in the percentage of
BLLs greater than or equal to 10 ug/dL. The findings in this report
suggest that levels exceeding the EPA action level of 15 ppb can
result in an increase in the percentage of BLLs greater than or equal
to 5 ug/dL. Homes with lead service pipes are older, and persons
living in these homes are more likely to be exposed to high-dose lead
sources (e.g., paint and dust hazards). For this reason, in all years
reported, the percentage of test results greater than or equal to 10
ug/dL and the percentage of test results greater than or equal to 5
ug/dL at addresses with lead service pipes were higher than at
addresses without lead service pipes.
The findings in this report are subject to at least three limitations.
First, the BLL surveillance data include multiple tests on the same
person, and persons with lead poisoning are tested more frequently
than those with low BLLs. Second, fingerstick tests are more subject
than venous samples to contamination by ambient lead (7). Finally,
neither the blood nor the water lead test results were collected from
a randomized sample. Water was collected from homes with a high
probability of having lead service pipes; the March 2004 BLL screening
program was limited to families living in homes with the highest water
lead levels, and the routine blood lead surveillance program focused
on identifying children at highest risk for lead exposure. For these
reasons, the percentages of BLLs greater than or equal to 5 ug/dL or
greater than or equal to 10 ug/dL reported probably are higher than
those found in the general population. However, none of these factors
should affect the relative differences between percentage of tests
greater than or equal to 5 ug/dL by water line type, nor do they
explain the change in trajectory of the percentage of tests greater
than or equal to 5 ug/dL by year after 2000.
The cause of the elevated water lead levels in DC is under review.
Although the increase is associated temporally with the change in the
disinfection process from chlorine to chloramines that occurred in
November 2000, whether this change contributed to increased lead in
the water is unknown.
Because no threshold for adverse health effects in young children has
been demonstrated (6), public health interventions should focus on
eliminating all lead exposures in children (8). Lead concentrations in
drinking water should be below the EPA action level of 15 ppb.
Officials in communities that are considering changes in water
chemistry or that have implemented such changes recently should assess
whether these changes might result in increased lead in residential
tap water. EPA has asked all state health and environmental officials
to monitor lead in drinking water at schools and day care centers.
More information about lead poisoning is available from CDC at
[hyperlink, http://www.cdc.gov/nceh/lead/lead.htm].
Acknowledgments:
This report is based in part on data collected by SB Adams, LC Cooper,
PhD, KJ Elenberg, JM Gusto, MPH, JE Hardin, P Karikari-Martin, MPH, L
Velazquez, PharmD, AA Walker, US Public Health Svc.
References:
1. Agency for Toxic Substances and Disease Registry. Toxicological
profile for lead. Atlanta, Georgia: U.S. Department of Health and
Human Services, Agency for Toxic Substances and Disease Registry,
1999. Available at [hyperlink,
http://www.atsdr.cdc.gov/toxprofiles/tpl3.html].
2. District of Columbia Department of Health. Health advisory: lead in
Washington, DC. February 26, 2004. Available at [hyperlink,
http://www.dchealth.dc.gov].
3. CDC. Preventing lead poisoning in young children: a statement by
the Centers for Disease Control--October 1991. Atlanta, Georgia: U.S.
Department of Health and Human Services, Public Health Service, CDC,
1991.
4. Canfield RL, Henderson CR Jr, Cory-Slechta DA, Cox C, Jusko TA,
Lanphear BP. Intellectual impairment in children with blood lead
concentrations below 10 pg per deciliter. N Engl J Med 2003;348:1517-
26.
5. Bellinger DC, Needleman HL. Intellectual impairment and blood lead
levels. N Engl J Med 2003;349:500-2.
6. Schwartz J. Low-level lead exposure and children's IQ: a meta-
analysis and search for a threshold. Environ Res 1994;65:42-55.
7. Schlenker TL, Fritz CJ, Mark D, et al. Screening for pediatric lead
poisoning: comparability of simultaneously drawn capillary and venous
blood samples. JAMA 1994;271:1346-8.
8. Rogan WJ, Ware JH. Exposure to lead in children--how low is low
enough? N Engl J Med 2003;348:1515--6.
Table: Blood lead levels (13LLs) of residents in homes with >300 parts
per billion In drinking water, by age group ”District of Columbia,
March 2004:
Age group (years): 1-3 (n = 17);
BLL (ug/dL): Median: 3;
BLL (ug/dL): Range: 1-6.
Age group (years): 6-13 (n = 13);
BLL (ug/dL): Median: 2;
BLL (ug/dL): Range: 1-4.
Age group (years): 16-40 (a = 56);
BLL (ug/dL): Median: 3;
BLL (ug/dL): Range: 1-14.
Age group (years): 41-60 (n = 69);
BLL (ug/dL): Median: 4;
BLL (ug/dL): Range: 1-20.
Age group (years): greater than or equal to 61 (n = 46);
BLL (ug/dL): Median: 6;
BLL (ug/dL): Range: 2-22.
Total (n = 201).
[End of table]
Figure: Percentage of tests with elevated blood lead levels, by year
and water-line type ” District of Columbia. January 1998”September
2003:
[Refer to PDF for image: multiple line graph]
The graph plots percentage for each year 1998-2003 for the following:
less than or equal to 5 ug/dL lead service pipe;
less than or equal to 5 ug/dL no lead service pipe;
less than or equal to 10 ug/dL lead service pipe;
less than or equal to 10 ug/dL no lead service pipe.
[End of figure]
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[End of section]
Appendix II: 2010 Letter Clarifying Information about the 2004
Morbidity and Mortality Weekly Report Article:
On May 20, 2010, the Centers for Disease Control and Prevention (CDC)
sent the following letter to state and local Childhood Lead Poisoning
Prevention Program managers to address confusion related to the first
sentence in the Editorial Note section of the 2004 Morbidity and
Mortality Weekly Report article, which contained an incorrect
statement. Additionally, the letter presented results of a recent
analysis that included new blood lead level data that had not been
available to CDC in 2004. The letter is presented here in its
electronic version, which was accessed from CDC's Web site.
Centers for Disease Control and Prevention:
Your Online Source for Credible Health Information:
Important update:
Washington, D.C. Blood Lead Level Tests:
May 20 2010:
Lead Poisoning Prevention Program Managers:
Dear Colleague,
The Centers for Disease Control and Prevention, Healthy Homes and Lead
Poisoning Prevention Branch has recently acquired and analyzed blood
lead test results that were not available to us in 2004 during the
public health response to elevated drinking water lead levels in
Washington DC and the report of blood lead levels in Washington
published in Morbidity Mortality Weekly Review in April 2004.[Footnote
1]
A substantial number of blood lead test results from blood specimens
collected in 2003 were unavailable for the analysis published in the
2004 MMWR. In 2009, CDC acquired all known 2003 blood lead test
results for DC residents and completed a reanalysis to determine if
the addition of the previously missing tests altered the results
reported in the 2004 MMWR. The reanalysis included the 9,765 tests
used in the original analysis plus 1,753 tests reported in
surveillance data after the MMWR was published and 12,168 tests that
had not been included in the surveillance files. The reanalysis showed
that addition of the missing test data led to a decrease in the
proportion of tests with blood lead levels greater than or equal to 5
ug/dL or greater than or equal to 10 u/dL in 2003, regardless of the
type of service line supplying water to the home (Table 1). These
results do not change CDC's original conclusions that ... the
percentage of test results greater than 10 ug/dL and the percentage of
test results greater than 5 ug/dL at addresses with lead service pipes
were higher than at addresses without lead service pipes.
Table 1: The Percent of Elevated Blood Lead Tests in 2003 by Type of
Water Service Line and Data Set:
Service Line Type: Lead Service Line;
2004 MMWR Dataset[A] percentage greater than or equal to 10 ug/dL: 7.6;
Dataset Reported in 2009[B] percentage greater than or equal to 10
ug/dL: 6.0 1;
2004 MMWR Dataset[A] percentage greater than or equal to 5 ug/dL: 31.2;
Dataset Reported in 2009[B] percentage greater than or equal to 5
ug/dL: 26.5 3.
Service Line Type: No Lead Service Line;
2004 MMWR Dataset[A] percentage greater than or equal to 10 ug/dL: 2.8
Dataset Reported in 2009[B] percentage greater than or equal to 10
ug/dL: 2.0 2;
2004 MMWR Dataset[A] percentage greater than or equal to 5 ug/dL: 15.6;
Dataset Reported in 2009[B] percentage greater than or equal to 5
ug/dL: 13.4 4.
[A] n = 9,683;
[B] n = 10,637.
The water service line type was unknown for 2,670 tests.
1. p = 0.09;
2. p less than 0.001;
3. p = 0.007;
4. p less than 0.001.
[End of table]
The first sentence of the Editorial Note in the 2004 MMWR referred to
a cross-sectional study of homes with very high lead levels in
drinking water and stated that ... no children were identified with
blood lead greater than or equal to 10 ug/dL, even in homes with the
highest water lead levels. This sentence was misleading because it
referred only to data from the cross-sectional study, and did not
reflect findings of concern from the separate longitudinal study that
showed that children living in homes serviced by a lead water pipe
were more than twice as likely as other DC children to have had a
blood lead level 10 ug/dL. CDC reiterates here a key message from the
2004 article ... because no threshold for adverse health effects in
young children has been demonstrated (no safe blood level has been
identified), all sources of lead exposure for children should be
controlled or eliminated. Lead concentrations in drinking water should
be below the U. S. Environmental Protection Agency's action level of
15 parts per billion.
The complete report of the reanalysis can be found at [hyperlink,
http://www.cdc.gov/nceh/lead/leadinwater/].
I would also like to bring to your attention two other strategies to
reduce children's exposure to lead in water. First, on our website
[hyperlink, http://www.cdc.gov/nceh/lead/waterlines.htm] you can find a
letter dated January 12, 2010 that discusses recent research related
to blood lead levels and partial replacement of lead water service
lines. This research indicates that partial lead service line
replacement is associated with increased risk for blood lead levels of
5 ug/dL or 10 ug/dL. CDC has also recommended that state and or local
lead programs work closely with the agency responsible for oversight
of water authority compliance with the lead and copper rule to ensure
that water samples are taken when inspections are done for children
with elevated blood lead levels in areas where the water lead levels
exceed the EPA water lead action level of 15 ppb.
Best Wishes,
Mary Jean Brown ScD, RN:
Chief, Healthy Homes and Lead Poisoning Prevention Branch:
Centers for Disease Control and Prevention:
4770 Buford Highway NE:
Atlanta, GA 30341:
Footnote:
[1] Stokes L, Onwuche NC, Thomas P, et al., Blood Lead Levels in
Residents of Homes with Elevated Lead in Tap Water ” District of
Columbia, 2004; MMWR Weekly, April 2, 2004, 83(12); 268-270.
Page last reviewed: May 20, 2010.
Page last updated: June 10, 2010.
[End of section]
Appendix III: May 21, 2010, Notice Clarifying Information about the
2004 Morbidity and Mortality Weekly Report Article:
On May 21, 2010, the Centers for Disease Control and Prevention (CDC)
published the following Notice to Readers in the Morbidity and
Mortality Weekly Report (MMWR) to clarify information about the first
sentence in the Editorial Note in the 2004 MMWR article and to present
results of a recent analysis that included new blood lead level data
that had not been available to CDC in 2004. The Notice to Readers is
presented here in its electronic version, which was accessed from
CDC's Web site.
CDC Centers for Disease Control and Prevention:
Your Online Source for Credible Health Information:
Morbidity and Mortality Weekly Report (MMWR):
Notice to Readers: Examining the Effect of Previously Missing Blood
Lead Surveillance Data on Results Reported in MMWR:
Weekly:
May 21, 2010/59(19);592:
During 2000-2003, the District of Columbia (DC) experienced very high
concentrations of lead in drinking water. In February 2004, the DC
Department of Health requested assistance from CDC to assess health
effects of elevated lead levels in residential tap water. CDC reviewed
available blood lead surveillance data for the period 1998--2003 and
reported the findings of a longitudinal analysis and cross-sectional
study in MMWR on April 2, 2004[Footnote 1].
A substantial number of blood lead test results from blood specimens
collected in 2003 were unavailable for the analysis published in the
2004 MMWR report. In 2009, CDC acquired all known 2003 blood lead test
results for DC residents and completed a reanalysis to determine
whether the addition of the previously missing tests altered the
previously reported results. The complete reanalysis is available at
[hyperlink, http://www.cdc.gov/nceh/lead/leadinwater].
The reanalysis surveillance included in led to a decrease ug/dL in
2003, results do and the percentage than at addresses included the
9,765 tests used in the original analysis, plus 1,753 tests reported
in data after the MMWR report was published, and 12,168 tests that had
not been the surveillance files. The reanalysis showed that addition
of the missing test data in the percentage of tests with elevated
blood lead levels greater than or equal to 5 ug/dL or greater than or
equal to 10 ug/dL, in 2003 regardless of the type of service line
supplying water to the home (Table). These not change CDC's original
conclusions that "the percentage of test results aim ug/dL of test
results ug/dL at addresses with lead service pipes were higher
without lead service pipes."
In the 2004 MMWR report, the first sentence of the Editorial Note
referred to a cross-sectional study of homes with very high lead
levels in drinking water and stated that "no children were identified
with blood lead greater than or equal to 10 ug/dL, even in homes with
the highest water lead levels." This sentence was misleading because
it referred only to data from the cross-sectional study and did not
reflect findings of concern from the separate longitudinal study that
showed that children living in homes serviced by a lead water pipe
were more than twice as likely as other DC children to have had a
blood lead level ..1.0 ug/dL. CDC reiterates here a key message from
the 2004 report: "because no threshold for adverse health effects in
young children has been demonstrated," no safe blood level has been
identified, and all sources of lead exposure for children should be
controlled or eliminated. "Lead concentrations in drinking water
should be below the U.S. Environmental Protection Agency's action
level of 15 ppb."
Reference:
1. CDC. Blood lead levels in residents of homes with elevated lead in
tap water--District of Columbia, 2004. MMWR 2004;53m:268-70.
Table: Percentage of tests with elevated blood lead levels, by type of
water service line[A] and data set --- District of Columbia, 2003:
Water service line type: Lead service line;
Surveillance data set used in 2004 MMWR report[B] percentage greater
than or equal to 10 ug/dL: 7.6;
All known blood lead tests[C] percentage greater than or equal to 10
ug/dL: 6.8;
Surveillance data set used in 2004 MMWR report[B] percentage greater
than or equal to 5 ug/dL: 31.2;
All known blood lead tests[C] percentage greater than or equal to 5
ug/dL: 30.2.
Water service line type: No lead service line;
Surveillance data set used in 2004 MMWR report[B] percentage greater
than or equal to 10 ug/dL: 2.8;
All known blood lead tests[C] percentage greater than or equal to 10
ug/dL: 2.3;
Surveillance data set used in 2004 MMWR report[B] percentage greater
than or equal to 5 ug/dL: 15.6;
All known blood lead tests[C] percentage greater than or equal to 5
ug/dL: 14.9.
[A] Water service line type was unknown for 2,670 tests.
[B] Source: CDC. Blood lead levels in residents of homes with elevated
lead in tap water---District of Columbia, 2004. MMWR 2004;53:268-70;
n = 9,683.
[C] n = 21,016.
[End of table]
Use of trade names and commercial sources is for identification only
and does not imply endorsement by the U.S. Department of Health and
Human Services.
References to non-CDC sites on the Internet are provided as a service
to MMWR readers and do not constitute or imply endorsement of these
organizations or their programs by CDC or the U.S. Department of
Health and Human Services. CDC is not responsible foe the content of
pages found at these sites. URL addresses listed in MMWR were current
as of the date of publication.
All MMWR HTML versions of articles are electronic conversions from
typeset documents. This conversion might result in character
translation or format errors in version [hyperlink,
http://www.cdc.gov/mmwr] and/or the original MMWR paper copy for
printable versions of official text, figures, and tables. An original
paper copy of this can be obtained from the Superintendent of
Documents, U.S. Government Printing Office (GPO), Washington, DC 20402-
9371; telephone: (202) 512-1800. Contact GPO for current prices.
Questions or messages regarding errors should be addressed to
minwrq@cdc.gov.
Page last reviewed: May 21, 2010.
Page last updated: May 21, 2010.
Content source: Centers for Disease Control and Prevention.
[End of section]
Appendix IV: June 25, 2010, Notice Clarifying Information about the
2004 Morbidity and Mortality Weekly Report Article:
On June 25, 2010, the Centers for Disease Control and Prevention (CDC)
published the following Notice to Readers in the Morbidity and
Mortality Weekly Report (MMWR) that noted the limitations of the
results of an analysis in the 2004 MMWR article. The Notice to Readers
is presented here in its electronic version, which was accessed from
CDC's Web site.
CDC Centers for Disease Control and Prevention:
Your Online Source for Credible Health Information:
Morbidity and Mortality Weekly Report (MMWR):
Notice to Readers: Limitations Inherent to a Cross-Sectional
Assessment of Blood Lead Levels Among Persons Living in Homes with
High Levels of Lead in Drinking Water:
Weekly:
June 25, 2010/59(24);751:
During 2000--2003, the District of Columbia (DC) experienced very high
concentrations of lead in drinking water. In February 2004, the DC
Department of Health requested assistance from CDC to assess health
effects of elevated lead levels in residential tap water. CDC reviewed
available blood lead surveillance data for the period 1998-2003 and
reported the findings of a longitudinal analysis and a cross-sectional
assessment in MMWR on April 2, 2004[Footnote 1].
The cross-sectional assessment was designed for a limited purpose, to
take a snapshot of blood lead levels in the homes with the highest
levels of lead in water and to provide service to children at risk for
lead poisoning. The assessment had several design limitations. The
data were not collected in a manner that would allow a comparison
between the amount of lead consumed in drinking water and blood lead
levels. Additionally, the blood lead levels did not necessarily
represent what peak blood levels might have been before the problems
with the DC water supply were recognized. Thus, these results should
not be used to make conclusions about the contribution of water lead
to blood lead levels in DC, to predict what might occur in other
situations where lead levels in drinking water are high, or to
determine safe levels of lead in drinking water. The dataset for the
cross-sectional assessment is not available to CDC for further
analysis.
CDC has conducted a more thorough analysis of trends in DC blood lead
levels for the period 1998-2006, which confirms the conclusions in the
original analysis. In addition, CDC has examined the association
between DC blood lead levels and the partial replacement of leaded
drinking water service lines. Preliminary data show that strategies of
replacing only the publicly owned portion of lead pipes (known as
partial mitigation) do not decrease (and might increase) blood lead
levels. CDC notified the U.S. Environmental Protection Agency, DC, and
other jurisdictions when these preliminary findings became known, and
is following up with more definitive guidance. These findings have
been submitted to a scientific journal for publication. The
information related to the preliminary findings concerning partial
lead pipe replacement is available at [hyperlink,
http://www.cdc.gov/nceh/lead/leadinwater].
Reference:
1. CDC. Blood lead levels in residents of homes with elevated lead in
tap water--District of Columbia. 2004. MMWR 2004:5:1:268-70.
Use of trade names and commercial sources is for identification only
and does not imply endorsement by the U.S. Department of Health and
Human Services.
References to non-CDC sites on the Internet are provided as a service
to MMWR readers and do not constitute or imply endorsement of these
organizations or their programs by CDC or the U.S. Department of
Health and Human Services. CDC is not responsible for the content of
pages found at these sites. URL addresses listed in MMWR were current
as of the date of publication.
All MMWR HTML versions of articles are electronic conversions from
typeset documents. This conversion might result in character
translation or format errors in the HTML version. Users are referred
to the electronic PDF version [hyperlink, http://www.cdc.gov/mmwr]
and/or the original MMWR paper copy for printable versions of official
text, figures, and tables. An original paper copy of this issue can be
obtained from the Superintendent of Documents, U.S. Government
Printing Office (GPO), Washington, DC 20402-9371; telephone: (202) 512-
1800. Contact GPO for current prices.
Questions or messages regarding errors in formatting should be
addressed to mmwrq@cdc.gov.
Page last reviewed: June 25, 2010.
Page last updated: June 25, 2010.
Content source: Centers for Disease Control and Prevention.
[End of section]
Appendix V: Comments from the Centers for Disease Control and
Prevention:
Department Of Health And Human Services:
Office Of The Secretary:
Assistant Secretary for Legislation:
Washington, DC 20201:
February 22, 2011:
Cynthia Bascetta:
Managing Director, Health Care:
U.S. Government Accountability Office:
441 G Street N.W.
Washington, DC 20548:
Dear Ms. Bascetta:
Attached are comments on the U.S. Government Accountability Office's
(GAO) draft report entitled, "Lead In Tap Water: CDC Communication
About Health Effects Needs Improvement" (GAO 11-279).
The Department appreciates the opportunity to review this report prior
to publication.
Sincerely,
Signed by:
Jim R. Esquea:
Assistant Secretary for Legislation:
Attachment:
[End of letter]
General Comments Of The Department Of Health and Human Services (HHS)
On The Government Accountability Office's (GAO) Draft Report Entitled.
"Lead In Tap Water: CDC Communication About Health Effects Needs
Improvement" (GAO-11-279):
The Department appreciates the opportunity to review and comment on
this draft report. The Centers for Disease Control and Prevention
(CDC) generally concurs with the GAO's recommendations and
respectfully submits the following general comments.
* The Environmental Protection Agency (EPA) is responsible for
periodically reviewing its drinking water contaminant rules and
revising them if appropriate at least once every six years as required
by the Safe Drinking Water Act (SDWA). The EPA is currently conducting
a review of the lead and copper rule.
* CDC's activities are distinct from those of EPA. CDC's role in
preventing lead poisoning in children supports state and city programs
and works with other Federal agencies to monitor the blood lead levels
of children in the United States, to establish guidelines that protect
children from lead, and to investigate situations where children have
been exposed to lead. CDC's Childhood Lead Poisoning Prevention
Program (CLPPP) provides funding to state and local health departments
to determine the extent of childhood lead poisoning by screening
children for elevated blood lead levels and ensuring that lead-
poisoned infants and children receive medical and environmental follow-
up (case management). This program also supports the development of
state and local government agencies' capacity to prevent lead
poisoning in their communities through the development of protective
policies.
* CDC made efforts in 2004 to stop ongoing exposures to lead from
drinking water in the District of Columbia. CDC assisted in efforts to
notify vulnerable members of the community, assure that filters or
alternative sources of drinking water were available, and to increase
screening of blood lead levels.
* In December 2010, CDC published its complete analysis of the effects
of lead in D.C. tap water from 1998-2006. The citation for the article
is Environmental Research 111 (2011) 67-74.
* Related to the GAO's first recommendation, CDC plans to publish an
article in the MMWR Recommendations & Reports publication. The article
will focus on what is known about tap water as a source of lead
exposure. It will also summarize the potential health effects in
children from lead exposures. The article will draw from several
previously released documents including those already available on the
CDC Childhood Lead Poisoning Prevention Web site, the 2007 ATSDR
Toxicological Profile on lead, CDC's analysis of childhood blood lead
levels in DC from 1998-2006, the EPA's 2006 Air Quality Criteria for
Lead, and other EPA sources.
* Related to the GAO's second recommendation, when CDC becomes aware
of significant errors of understanding or perception resulting from
public health information disseminated by CDC, the agency may pursue
one or more of the following actions as appropriate under the
circumstances:
1. For factual errors in content or data, CDC will publish errata,
letters to the editor, or notice to readers, in the original source
publication.
2. For errors of understanding or perception in which there is a
persistent, broad or otherwise significant misinterpretation of the
factual data or conclusions which could cause a threat to public
health or safety or jeopardize the credibility of the agency, CDC will
present the scientific conclusions in clear language in one or more of
the following venues.
a. Publication on the www.cdc.gov web site.
b. Direct outreach to the news and electronic media, including via
press releases or letters to the editor.
c. Direct communication with state and local health departments,
clinicians and professional organizations.
d. Direct communication with community organizations, advocacy groups
and public meetings.
The CDC response will be jointly led by the Offices of the Associate
Director for Science and the Associate Director for Communication.
These procedures will be actionable immediately upon approval by the
CDC Director, concurrent with the development and approval process of
agency policies.
[End of section]
Appendix VI: GAO Contact and Staff Acknowledgments:
GAO Contact:
Cynthia A. Bascetta, (202) 512-7114 or bascettac@gao.gov:
Staff Acknowledgments:
In addition to the contact named above, Karen Doran, Assistant
Director; April W. Brantley; Natalie Herzog; Amy C. Leone; Lisa
Motley; and Roseanne Price made key contributions to this report.
[End of section]
Footnotes:
[1] Tap water includes water used for drinking, cooking, and preparing
infant formula and juice.
[2] Exposure to lead, which can lead to elevated BLLs, and potentially
to lead poisoning, can affect nearly every system in the body,
including the nervous, reproductive, renal, cardiovascular, and
gastrointestinal systems. This can also cause behavior problems and
learning disabilities in young children.
[3] Lead poisoning occurs once a child's BLL reaches 10 micrograms of
lead per deciliter of blood.
[4] Healthy People 2020 is a national health promotion and disease
prevention initiative that strives to identify nationwide health
improvement priorities and to promote quality of life, healthy
development, and healthy behaviors across all life stages. The goal to
eliminate elevated BLLs in children was previously an objective for
the Healthy People 2010 initiative.
[5] The U.S. Public Health Service Commissioned Corps consists of more
than 6,500 public health professionals who support federal agencies'
health promotion and disease prevention efforts and public health
science activities.
[6] Throughout, we refer to the District of Columbia as the District.
[7] L. Stokes et al., "Blood Lead Levels in Residents of Homes with
Elevated Lead in Tap Water-District of Columbia, 2004," Morbidity and
Mortality Weekly Report, vol. 53 (Apr. 2, 2004). CDC posted this
article online at [hyperlink,
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5312a6.htm].
[8] In 1991, CDC set a "level of concern" for children at the lead
poisoning threshold of 10 micrograms per deciliter of blood in
response to evidence associating BLLs of 10 micrograms per deciliter
or greater with adverse health effects and has noted that this BLL
should prompt public health actions. Actions to reduce lead exposure
can include the use of water filters on taps in homes.
[9] CDC also stated that it recognizes that a BLL of 10 micrograms per
deciliter did not define a threshold for the harmful effects of lead
and that research conducted since 1991 has strengthened the evidence
that children's physical and mental development can be affected at
BLLs of less than 10 micrograms per deciliter. In other words, there
currently is no demonstrated safe concentration of lead in blood, and
adverse health effects can occur at lower concentrations.
[10] In an effort to prevent and mitigate the adverse health
consequences resulting from elevated lead levels in drinking water,
EPA set a limit of 15 parts per billion of lead in water as a
regulatory standard for water utilities. Water utilities in violation
of this limit must take specified actions to reduce their water lead
levels. Some of the households in the District had water lead levels
of 300 parts per billion or greater.
[11] NCEH is a component of CDC that plans, directs, and coordinates
programs to maintain and improve the health of the American people by
addressing public health effects resulting from noninfectious,
nonoccupational environmental exposures, such as lead.
[12] CDC's other scientific publications are Preventing Chronic
Disease and Emerging Infectious Diseases.
[13] Deteriorating lead-based paint and lead-contaminated dust are the
main sources of exposure to lead for U.S. children. Lead-based paints
were banned for use in housing in 1978. All houses built before 1978
are likely to contain some lead-based paint. Previously, leaded
gasoline was an important source of exposure until the use of leaded
gasoline was phased out in the 1980s. This decline was complemented by
the ban on the sale of leaded gasoline as of December 31, 1995, under
amendments to the Clean Air Act.
[14] 42 U.S.C. §§ 1396a(a)(43), 1396d(r).
[15] Until March 14, 2007, the first blood test was to be performed
between 6 and 9 months. See 2006 D.C. Stat. 16-265.
[16] D.C. Code Ann. § 7-871.03(b).
[17] D.C. Code Ann. § 7-871.03(c), (d).
[18] These public health actions could include health officials
distributing information to the public about preventing exposure to
lead in water, such as recommendations for the use of water filters on
residential water taps, for the consumption of only bottled water, or
for clinicians to perform diagnostic blood lead tests on children
suspected of having lead exposure or an elevated BLL.
[19] In November 2010, CDC's Advisory Committee on Childhood Lead
Poisoning Prevention--whose goal is to provide advice to assist the
nation in reducing the incidence and prevalence of childhood lead
poisoning--published "Guidelines for the Identification and Management
of Lead Exposure in Pregnant and Lactating Women," which provides
guidance regarding blood lead testing and follow-up care for pregnant
and lactating women with lead exposure. While CDC states that there is
no apparent threshold below which adverse effects of lead do not occur
and has not identified an allowable exposure level or level of concern
to connote a safe or unsafe level of exposure for either the mother or
the fetus, the guidelines recommend follow-up activities to identify
and control lead sources in the home beginning at BLLs 5 µg/dL in
pregnant and lactating women rather than at 10 µg/dL.
[20] Pub. L. No. 100-572, § 3, 102 Stat. 2884, 2887-89 (codified as
amended at 42 U.S.C. § 247b-1).
[21] The National Health and Nutrition Examination Survey (NHANES) is
a national survey, and starting with the period 1999 to 2000, public
releases of data collected on a biannual basis occur at least twice a
year, or more often if needed. The most recent survey period for which
data were available was 2007 to 2008. The NHANES is the source of data
used to measure progress for the Healthy People 2020 objective of
eliminating elevated BLLs in children aged 1 to 5 years.
[22] The advisory committee also provides advice and guidance to HHS's
Secretary and Assistant Secretary for Health.
[23] Pub. L. No. 93-523, 88 Stat. 1660 (1974) (codified as amended at
42 U.S.C. §§ 300f-300j-25).
[24] 40 C.F.R. § 141.80(c)(1) (2010).
[25] The Washington Aqueduct changed its disinfection process after
EPA issued regulations requiring that water treatment systems reduce
the production of disinfection by-products that result from the use of
chlorine because of concerns that the by-products of chlorine were
carcinogenic. See 63 Fed. Reg. 69,390 (Dec. 16, 1998) (codified at 40
C.F.R. §§ 141.130-141.135).
[26] The 2004 MMWR article included the following limitations to its
findings: the BLL surveillance data included multiple tests on the
same person, and persons with lead poisoning are tested more
frequently than those with low BLLs; fingerstick tests, which were
used in some cases, are more subject than venous samples to
contamination by ambient lead; and neither the blood nor the water
lead test results were collected from a randomized sample.
[27] CDC posted the May 2010 letter online at [hyperlink,
http://www.cdc.gov/nceh/lead/blood_levels.htm]. The May 2010 Notice to
Readers was posted online at [hyperlink,
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5919a4.htm]. CDC also
included a link to the Notice to Readers at the top of the 2004 MMWR
article, which was posted online at [hyperlink,
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5312a6.htm].
[28] CDC posted the June 2010 Notice to Readers online at [hyperlink,
http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5924a6.htm]. CDC also
included a link at the top of the 2004 MMWR article, which was posted
at [hyperlink, http://www.cdc.gov/mmwr/preview/mmwrhtml/mm5312a6.htm].
[29] The newspaper article reported on a recently published CDC study
that presents the results of research and analyses on the relationship
between partial lead pipe replacement, water lead levels, and BLLs,
using data from the District. Lead pipe replacement--which can include
removal of the pipe lengths located on both public and private
property--is a method for reducing water lead levels by reducing
exposure to lead. CDC officials have stated that there is some
question as to the efficacy of this method of replacement based on
findings that indicate a temporary increase in lead levels may occur
when the work is being done. The research results were published
online in Environmental Research in November 2010 in an article
titled, "Association between children's blood lead levels, lead
service lines, and water disinfection, Washington, DC, 1998-2006."
[30] While the internal incident analysis did not provide specific
recommendations with a defined timeline for their completion, CDC
officials said the analysis served as an independent source of
information to the Director of CDC about CDC's role in the District.
It also identified potential areas of improvement to address the issue
of lead in water more broadly and to more effectively handle similar
situations regarding CDC communications in the future.
[31] See 75 Fed. Reg. 63,177 (Oct. 14, 2010). EPA is currently
evaluating potential long-term revisions to the Lead and Copper Rule,
which aims to protect public health by minimizing lead levels in
drinking water, primarily by reducing water corrosivity. The Lead and
Copper Rule established an action level of 15 ppb for lead in drinking
water.
[End of section]
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