This is the accessible text file for GAO report number GAO-11-803T 
entitled 'Safe Drinking Water Act: Improvements in Implementation Are 
Needed to Better Assure the Public of Safe Drinking Water' which was 
released on July 12, 2011. 

This text file was formatted by the U.S. Government Accountability 
Office (GAO) to be accessible to users with visual impairments, as 
part of a longer term project to improve GAO products' accessibility. 
Every attempt has been made to maintain the structural and data 
integrity of the original printed product. Accessibility features, 
such as text descriptions of tables, consecutively numbered footnotes 
placed at the end of the file, and the text of agency comment letters, 
are provided but may not exactly duplicate the presentation or format 
of the printed version. The portable document format (PDF) file is an 
exact electronic replica of the printed version. We welcome your 
feedback. Please E-mail your comments regarding the contents or 
accessibility features of this document to 

This is a work of the U.S. government and is not subject to copyright 
protection in the United States. It may be reproduced and distributed 
in its entirety without further permission from GAO. Because this work 
may contain copyrighted images or other material, permission from the 
copyright holder may be necessary if you wish to reproduce this 
material separately. 

United States Government Accountability Office: 


Before the Committee on Environment and Public Works, U.S. Senate: 

For Release on Delivery: 
Expected at 10:00 a.m. EDT:
Tuesday, July 12, 2011: 

Safe Drinking Water Act: 

Improvements in Implementation Are Needed to Better Assure the Public 
of Safe Drinking Water: 

Statement of David C. Trimble, Director:
Natural Resources and Environment: 


Madam Chairman Boxer, Ranking Member Inhofe, and Members of the 

I am pleased to be here today to discuss highlights of GAO's report on 
the Environmental Protection Agency's (EPA) implementation of 
requirements for determining whether additional drinking water 
contaminants warrant regulation. As you know, the number of potential 
drinking water contaminants is vast--as many as tens of thousands of 
chemicals may be used across the country, and EPA has identified more 
than 6,000 chemicals that it considers to be the most likely source of 
human or environmental exposure. The potential health effects of 
exposure to most of these chemicals, and the extent of their 
occurrence in drinking water, are unknown. Under 1996 amendments to 
the Safe Drinking Water Act, every 5 years EPA is to determine for at 
least five contaminants whether regulation is warranted, considering 
those that present the greatest public health concern. EPA issued 
final regulatory determinations in 2003 and 2008 on a total of 20 
contaminants, deciding in each case not to regulate. In fact, EPA did 
not recommend any new contaminants for regulation until February 2011, 
when it reversed its controversial 2008 preliminary decision to not 
regulate perchlorate, an ingredient in rocket fuel and other products. 

This statement summarizes our report being released today that (1) 
evaluates the extent to which EPA's implementation of the 1996 
amendments has helped assure the public of safe drinking water and (2) 
reviews the process and scientific analyses EPA used to develop the 
2008 preliminary decision to not regulate perchlorate.[Footnote 1] In 
preparing this testimony, we relied on our work supporting the 
accompanying report, which contains a detailed description of our 
scope and methodology. All of the work for this report was performed 
in accordance with generally accepted government auditing standards. 

Systemic Limitations in EPA's Implementation of Requirements for 
Determining Whether to Regulate Additional Contaminants Have Impeded 
Progress in Helping Assure the Public of Safe Drinking Water: 

As detailed in our report, we found the following concerning the 
extent to which EPA's implementation of the 1996 amendments has helped 
assure the public of safe drinking water. 

EPA Has Neither Identified the Drinking Water Contaminants of Greatest 
Public Health Concern Nor Fully Used Its Authority to Obtain Data for 
Making Regulatory Determinations: 

EPA has not effectively implemented the 1996 amendments' requirement 
to consider, for regulatory determinations, contaminants that present 
the greatest public health concern. The contaminant candidate list 
[Footnote 2] that the amendments require EPA to develop every 5 years 
represents one level of prioritization as EPA selects from a larger 
universe those contaminants the agency believes warrant consideration 
for regulation. However, EPA officials told us that its Office of 
Water, which has primary responsibility for implementing the 
requirements of the Safe Drinking Water Act, has not (1) further 
ranked or otherwise prioritized the contaminants on the list on the 
basis of public health concern or (2) prioritized contaminants on the 
basis of public health concern when selecting them for regulatory 
determinations. In fact, for 16 of the 20 regulatory determinations 
made through January 2011, EPA based its decisions to not regulate on 
its assessment that public exposure to these drinking water 
contaminants was minimal--that is, there was limited or no occurrence 
of them in public drinking water systems. An EPA official described 
these determinations as addressing the "low hanging fruit"--rather 
than the contaminants of greatest public health concern. Overall, data 
availability--not consideration of greatest public health concern--has 
been the primary driver of EPA's selection of contaminants for 
regulatory determinations. 

To assess unregulated contaminants against the statutory criteria, EPA 
needs sufficient information on both (1) the occurrence of these 
contaminants in drinking water--called occurrence data--to assess the 
population potentially being exposed and the levels of that exposure 
and (2) the human health effects that may result from exposure to the 
contaminants in drinking water. EPA has made some progress in 
developing the occurrence and health effects data it needs, but for 
many contaminants EPA lacks sufficient occurrence and health effects 
data to support regulatory determinations, which continues to limit 
its ability to make these decisions. Specifically, in finalizing its 
current candidate list comprising 116 contaminants, EPA indicated that 
the agency lacked sufficient occurrence or health effects data, or 
both, for making regulatory determinations for at least 100 of the 
contaminants. Moreover, in 2009 EPA's Science Advisory Board 
recommended that the agency further prioritize among the contaminants 
on the candidate list because the list was too large, noting that 
prioritizing the contaminants on the list would help the agency meet 
its goal of selecting contaminants for regulatory determinations that 
"have the greatest opportunity to improve the safety of drinking water 
and protect public health." 

In addition, in its testing program for unregulated contaminants--
which can provide key occurrence data to inform regulatory 
determinations--EPA has fallen short in both the number of 
contaminants tested and the utility of the data provided because of 
management decisions and program delays. For example, despite having 
the authority to require testing for up to 30 drinking water 
contaminants in each 5-year cycle, in implementing the first two 
cycles of the testing program, EPA required that only 51 contaminants 
be tested--thereby not availing itself of its authority to obtain 
occurrence data for 9 additional contaminants. Moreover, in some 
cases, the occurrence data EPA used to support its regulatory 
determinations were based on testing (analytic) methods that were not 
sufficiently sensitive to identify the presence of contaminants at 
EPA's health reference level--the level that EPA uses in assessing 
whether to regulate specific contaminants.[Footnote 3] For 9 of the 20 
contaminants for which EPA made regulatory determinations in 2003 and 
2008, the minimum reporting level--the lowest level of a contaminant 
at which detections can be reported under testing protocols--exceeded 
EPA's health reference level. For example, for dieldrin--an 
insecticide banned by EPA for all uses in 1987 because of concerns 
about harm to human health and its ability to persist in the 
environment for decades--the agency relied on testing data obtained 
using minimum reporting levels ranging from 10 to 2,200 times higher 
than EPA's health reference level.[Footnote 4] EPA reported in its 
regulatory determination documents for dieldrin that it was detected 
in 0.06 percent of samples.[Footnote 5] However, in subsequent testing 
of source water for drinking water wells using more sensitive tests 
with minimum reporting levels near and below EPA's health reference 
level, the U.S. Geological Survey (USGS) detected dieldrin in 3.1 
percent of public well samples. Importantly, nearly all of USGS's 
detections were at levels above EPA's health reference level. USGS was 
able to detect dieldrin--and determine its presence above EPA's level 
of public health concern--in these groundwater well samples because it 
used a lower minimum reporting level for its testing than EPA used for 
its regulatory determinations. This is significant because, as USGS 
has reported, when a reporting level exceeds a health benchmark, a 
contaminant may be present at a concentration greater than the health 
benchmark but remain undetected, resulting in greater uncertainty in 
evaluating the contaminant concentration in the context of public 
health. EPA's testing program obtains data using minimum reporting 
levels that are often higher than those used by the USGS in its 
National Water Quality Assessment Program--ranging from 2 to more than 
600 times higher. 

In addition, the lack of timely health assessment data on drinking 
water contaminants continues to limit EPA's ability to make regulatory 
determinations. As a result of long-standing productivity problems in 
EPA's Integrated Risk Information System (IRIS) program--managed by 
the Office of Research and Development--EPA has not been able to keep 
its existing chemical toxicity assessments current or to complete 
assessments of the most important chemicals of concern.[Footnote 6], 
[Footnote 7] For example, from 1998 through 2008, the Office of Water 
lacked current IRIS assessments[Footnote 8] or other sufficient health 
information for 24 chemical contaminants on the candidate lists, and 
the Office of Research and Development completed assessments for only 
2 of the 24. Moreover, the Office of Water's current needs for health 
effects information for contaminants on the current candidate list 
have roughly doubled--when publishing the third candidate list in 
2009, EPA identified health effects information gaps for 44 of the 104 
chemicals on the list. Importantly, most of these contaminants with 
information gaps (1) are not on the IRIS agenda (i.e., assessments are 
neither under way nor planned) and (2) have not been identified by the 
Office of Water as priorities for IRIS assessments. 

EPA Lacks Policies or Guidance on Applying the Broad Statutory 
Criteria for Selecting Contaminants for Regulatory Determinations and 
Making the Determinations: 

The Safe Drinking Water Act requires EPA to select contaminants for 
regulatory determinations that present the greatest public health 
concern. However, EPA has not defined the characteristics of 
contaminants of greatest public health concern or developed a process 
for prioritizing the contaminants on its candidate list for regulatory 
determination on this basis. As a result, EPA lacks criteria and a 
process for identifying those contaminants on its candidate list that 
pose the greatest public health concern. 

Moreover, under the act, in selecting contaminants that present the 
greatest public health concern, EPA is to consider the effect of these 
contaminants on subpopulations at greater risk of adverse health 
effects from exposure to drinking water contaminants. In addition, EPA 
has stated that in making regulatory determinations, the act requires 
the agency to consider the effects the contaminants have on sensitive 
subpopulations, such as infants, children, those with kidney or liver 
diseases or weakened immune systems, and the elderly. Children, for 
example, represent a sensitive subpopulation because they may be more 
highly exposed to toxic substances in drinking water and at greater 
risk of adverse health effects than adults as a result of consuming 
more water per unit of body weight than adults. Children may also have 
increased susceptibility following exposure to drinking water 
contaminants because they continue to develop both behaviorally and 
physiologically throughout childhood. Furthermore, in 1995, EPA 
published its Policy on Evaluating Health Risks to Children, which 
states that the agency will "consider the risks to infants and 
children consistently and explicitly as a part of risk assessments 
generated during its decision making process," and to "the degree 
permitted by available data in each case, the Agency will develop a 
separate assessment of risks to infants and children or state clearly 
why this is not done." In 2006, EPA developed a general guidance 
document for all EPA program offices on implementing its 1995 
children's health policy, as well as several technical guidance 
documents that could help the Office of Water develop its own guidance 
specific to assessing the sensitivity of children to drinking water 

Notwithstanding the requirements of the Safe Drinking Water Act and 
EPA's 1995 children's health policy, the Office of Water did not 
implement a specific approach for considering children's health in 
developing its 2003 and 2008 regulatory determinations. In addition, 
the Office of Water has not developed guidance for its staff on when 
and how to analyze the effects of drinking water contaminants on 
children--or other sensitive subpopulations--for the purposes of 
identifying the drinking water contaminants of greatest concern on 
which to make regulatory determinations and to ensure it consistently 
and explicitly considers risks to children in making these 
determinations, such as by developing separate health reference levels 
for children. While EPA identified children as a sensitive population 
in 11 of the 20 regulatory determinations it completed in 2003 and 
2008, Office of Water officials confirmed that for these 20 
determinations, EPA did not develop separate health reference levels 
for children or make adjustments to its health assessments. 

The 1996 amendments also provide three broad criteria for EPA to use 
in making regulatory determinations, all of which must be met for EPA 
to determine that regulation is warranted. Notably, two of the 
criteria are so broadly stated that they could potentially be 
interpreted so as to lead to regulating all of the contaminants on 
candidate lists, some of them, or none of them. Specifically, the 
second statutory criterion--that a contaminant is "known to occur or 
there is a substantial likelihood that the contaminant will occur in 
public water systems with a frequency and at levels of public health 
concern"--is susceptible to varying interpretations. For example, 
different people may reasonably have differing views on the frequency 
and levels of occurrence that represent a public health concern. The 
third criterion--that regulation of the contaminant presents "in the 
sole judgment of the Administrator ... a meaningful opportunity for 
health risk reduction"--is expressly discretionary, and similarly open 
to differing interpretations. 

Importantly, the Office of Water has not developed policies or 
guidance to help EPA staff apply these broad criteria. Guidance that 
might help EPA staff apply the criteria transparently and consistently 
could, among other things, (1) define or set thresholds or parameters 
for assessing whether a contaminant occurs, or is substantially likely 
to occur, in public water systems with a frequency and at levels of 
public health concern and (2) provide factors or characteristics of 
situations that would present meaningful opportunities for health risk 
reduction. We note that such guidance could also serve as the basis 
for an internal review mechanism to help EPA ensure consistent 
implementation of the statutory criteria. Office of Water officials 
could not describe examples of what would meet the three criteria 
beyond stating that "there are no bright lines" and that they would 
"know it when we see it." Without clarifying guidance, EPA's 
regulatory determinations lack transparency, and EPA is at risk of 
making inconsistent determinations, undermining the program's 
credibility and the agency's ability to assure the public of safe 
drinking water. 

In the absence of regulations or guidance for applying the broad 
statutory criteria, EPA appears to apply an informal policy that 
contaminants warranting regulation should occur in public water 
systems on a "national" scale. For example, documents supporting EPA's 
2003 regulatory determinations state that the consideration of 
geographic distribution "is important because the agency is charged 
with developing national regulations, and it may not be appropriate to 
develop [national primary drinking water regulations] for regional or 
local contamination problems." In addition, some EPA officials serving 
on regulatory determination work groups told us that a contaminant 
must occur "nationally" to warrant a determination to regulate. 
Notably, however, the Safe Drinking Water Act does not require that 
contaminants be found in public water systems on a national basis for 
an Administrator to find a meaningful opportunity for health risk 
reduction. In fact, other parts of the statute provide for relief from 
monitoring and flexibilities for instances in which a contaminant 
occurs in certain areas but not in others. Moreover, there is nothing 
in the act's committee reports suggesting that a contaminant need 
occur nationally to support a decision to regulate. Without EPA 
guidance providing a definition or parameters, an informal "national 
occurrence" standard is open to shifting interpretations, potentially 
affecting the consistency and credibility of EPA's decision making. To 
the extent EPA is informally applying an unspecified national 
occurrence requirement for contaminants to be evaluated as occurring 
"with a frequency and at levels of public health concern," EPA is 
implementing a critical policy and interpretation of the Safe Drinking 
Water Act that has neither been defined nor subjected to public review. 

Further, regarding the third statutory criterion, EPA has not 
articulated guidelines or thresholds for how it is to assess whether 
regulating a specific contaminant would provide a meaningful 
opportunity for health risk reduction. The absence of guidelines on 
what scenario or scenarios might illustrate "a meaningful opportunity 
for health risk reduction" increases the potential for inconsistent 
decision making and reduces the decisions' transparency. 

In addition, EPA has not developed any guidance on the circumstances 
that would trigger a re-evaluation of a prior decision to not regulate 
or the process the agency would use in conducting a re-evaluation. In 
at least one instance--1,1,2,2-tetrachloroethane--an updated IRIS 
assessment became available after EPA's determination to not regulate, 
but the agency has not announced whether it will reconsider the 
determination. In addition, as discussed in the following section, the 
credibility of some of EPA's regulatory determinations was limited. As 
we reported, we believe EPA should consider whether it needs to re- 
evaluate any of its past determinations to not regulate in light of 
the systemic and individual shortcomings we identified. In the absence 
of policies or guidance that identifies the circumstances that would 
trigger such re-evaluations and the process the agency would use in 
conducting them, it is not clear how and when such re-evaluations 
would occur. 

The Credibility of Some of EPA's Regulatory Determinations As 
Presented in Federal Register Notices and Support Documents Is Limited 
by a Lack of Transparency, Clarity, and Consistency: 

The Safe Drinking Water Act requires EPA to ensure that, in its 
regulatory determinations, among other things, the presentation of 
information on public health effects is comprehensive, informative, 
and understandable. In addition, to the extent that EPA's regulatory 
determination notices and key support documents are transparent, 
clear, and consistent regarding the occurrence and health effects data 
the agency relied on, the credibility of the determinations is 
enhanced. However, for the regulatory determinations that EPA has made 
to date, some of the notices and support documents lack these key 
qualities. For example, as reflected in the following excerpts from 
EPA's regulatory determination documents for manganese and boron, 
EPA's presentation of health effects information on some contaminants 
lacked clarity, consistency, and transparency. 

* EPA's 2003 regulatory determination support document for manganese 
states unequivocally that there are "no data to indicate children are 
more sensitive to manganese than adults." However, EPA's 2003 health 
effects support document for manganese discusses studies that identify 
an association between exposure to manganese in drinking water and 
learning disabilities in children and concludes that additional 
studies are needed to investigate the possibility that children are 
more sensitive than adults. 

* EPA's regulatory determination support document for manganese notes 
that infants and newborns may be potentially susceptible to manganese 
toxicity, but this key document does not disclose that newborns may be 
exposed to high levels of manganese from infant formula or that these 
high levels of manganese in formula can be magnified when it is 
reconstituted with manganese-contaminated water. 

* In its regulatory support document for boron, the Office of Water 
(1) identified the primary adverse effects identified from studies of 
animals after chronic exposure to low doses of boron as generally 
involving the testes and the developing fetus and (2) stated that 
animal studies identify the developing fetus as "potentially sensitive 
to boron" and concluded that boron concentrations greater than the 
health reference level "might" have an effect on prenatal development. 
In contrast, the Office of Water's May 2008 Drinking Water Health 
Advisory for Boron--developed in conjunction with the regulatory 
determination and published just 2 months before the regulatory 
determination was issued--states that there are "compelling lines of 
evidence to suggest that the testicular morphological effects" 
reported in studies of animals are applicable to children. Also, the 
Office of Water's health advisory was not limited to prenatal exposure 
as it concluded that exposure to boron between birth and puberty may 
result in adverse cellular effects that would "affect testicular 

* EPA's Summary Document from the Health Advisory for Boron and 
Compounds provides an important warning regarding infants' exposure to 
boron in drinking water that is not included in either EPA's drinking 
water advisory for boron or its regulatory determination support 
document discussed above. Specifically, the summary document states 
that water containing boron "at levels above the HA [health advisory]" 
should not be used to prepare food or formula for infants. EPA does 
not identify which of the exposure duration health advisories it is 
referring to in this warning. 

In addition, EPA's regulatory determination documents lack 
transparency and clarity regarding how EPA determined its health 
reference levels were protective of children. In addressing seven of 
the contaminants in its 2003 regulatory determination notice for which 
EPA identified children as a sensitive subpopulation, EPA did not 
explain the potential effect of not developing separate health 
reference levels for children (or not making adjustments to its health 
assessments to reflect increased sensitivity) on its ability to ensure 
that the health reference levels used in the regulatory determinations 
were protective of children. Instead, EPA stated that the agency had 
not yet determined a protocol for making a regulatory determination 
for a chemical for which body weight and drinking water intake of 
infants or a particular childhood age group would be the basis of a 
regulatory action. As discussed earlier, health assessments based on 
adult weight and drinking water intake may not fully account for the 
risks to children of exposure to drinking water because they consume 
more water per unit of body weight and may have other 
susceptibilities, as well. Regarding its 2008 notice that included 
four contaminants for which children were identified as a sensitive 
subpopulation, Office of Water officials told us they would have 
developed separate assessments for children if they had determined 
children were "particularly sensitive" to the adverse health effects 
of contaminants being considered for regulation. However, EPA did not 
explain in its regulatory determination notices or support documents 
the basis for its determinations that children were not particularly 
sensitive to the adverse health effects of the contaminants considered 
for regulation--even for those contaminants, such as manganese and 
boron, for which EPA had determined children were a sensitive 
subpopulation. EPA also did not explain how the sensitivity of 
children can be evaluated in the absence of a separate assessment 
based on the weight and drinking water intake of children. 

Also, EPA's regulatory determination notices lack transparency and 
clarity regarding the limitations of new or updated health advisories 
the agency issued in conjunction with 9 decisions to not regulate. 
According to EPA, the advisories are to provide, for example, 
"guidance to communities that might be exposed to elevated 
concentrations." However, the regulatory determination notices do not 
acknowledge that when EPA determines regulation is not warranted but a 
health advisory is needed, it will generally be up to states, 
localities, and consumers to determine whether such contaminant levels 
are found in public water systems in their jurisdiction. Importantly, 
because public water systems are not typically required to test for 
the presence of unregulated contaminants, information on the levels of 
the contaminants in individual public water systems may be outdated or 
unavailable. While some states--such as California and Massachusetts--
can promulgate their own drinking water regulations, others are 
statutorily prohibited from, or otherwise constrained in, enacting 
more stringent regulations than EPA has promulgated or promulgating 
their own drinking water regulations for contaminants that EPA does 
not regulate. In addition, individuals may have to have their water 
tested by a laboratory to determine how much of these unregulated 
contaminants are present in their drinking water to heed, for example, 
EPA's warning in some cases to not use drinking water with 
contaminants in excess of certain levels to prepare infant food or 
formula. Moreover, EPA releases its drinking water advisories by 
posting them on its Web site and does not issue public notification of 
them, such as a press release, which potentially limits awareness of 
the health advisories. 

Our report provides information on the following limitations that also 
reduce the credibility of EPA's completed regulatory determinations: 
(1) EPA's explanations of the occurrence data EPA relied on to assess 
known and likely occurrence of contaminants in drinking water lack 
transparency, clarity, and consistency; (2) EPA's regulatory 
determinations lack clarity regarding its reliance on outdated and 
limited occurrence data to support some determinations; (3) the 
regulatory determination documents lack transparency and clarity 
regarding EPA's reliance on minimum reporting levels greater than its 
health reference levels; and (4) EPA lacked consistency and clarity in 
making determinations when IRIS assessments were either in process or 
needed to be updated. 

The Process and Analyses EPA Relied on to Support Its Preliminary 
Determination on Perchlorate Were Atypical, Lacked Transparency, and 
Limited the Agency's Independence in Developing and Communicating Its 
Scientific Findings: 

As detailed in our report, we found the following concerning the 
process and scientific analyses EPA used to develop its 2008 
preliminary determination to not regulate perchlorate. 

EPA Used a Less Inclusive, Less Transparent, and More Directive 
Process in Developing Its Preliminary Regulatory Determination on 
Perchlorate Than Its Usual Process: 

In contrast to EPA's usual regulatory determination process, which is 
managed by a work group of professional staff with relevant expertise 
from across the agency, EPA officials decided that the agency's 
continuing deliberations on perchlorate would be managed by a less 
inclusive, small group of high-level officials, such as the Deputy 
Administrator and several Assistant Administrators. Notably, EPA did 
not include the Office of Children's Health Protection in its small 
group despite EPA's and the National Academies' conclusion that iodide 
uptake inhibition from perchlorate exposure had been identified as a 
concern in connection with increasing the risk of neurodevelopmental 
impairment in fetuses of pregnant women with iodine deficiency and to 
developmental delays and decreased learning capability in infants and 
children. This group of high-level officials managed the regulatory 
determination process for perchlorate both within EPA and externally 
with the Perchlorate Interagency Working Group,[Footnote 9] whose work 
was coordinated by the Council on Environmental Quality.[Footnote 10] 
According to an EPA briefing document, the Perchlorate Interagency 
Working Group was established in 2002 "to identify and help resolve 
perchlorate science and science policy issues." 

In contrast to the usual process EPA used for its regulatory 
determinations, in which EPA staff with relevant expertise develop and 
submit options to the Assistant Administrator for the Office of Water 
for review and selection, the Assistant Administrator directed the 
Office of Water staff in developing the preliminary determination for 
perchlorate to draft a preliminary determination that reflected the 
agency's decision to not regulate perchlorate and to support it with a 
detailed and specific rationale that EPA and other members of the 
Perchlorate Interagency Working Group had agreed to, under the 
leadership and coordination of the Council on Environmental 
Quality.[Footnote 11] EPA Office of Water officials told us that they 
believed this agreement--which is not part of the record for the 
preliminary regulatory determination--was developed by senior 
officials from the Council on Environmental Quality, the Department of 
Health and Human Services (HHS), EPA, the Office of Management and 
Budget (OMB), and the U.S. Department of Agriculture. The agreement 
focused on how EPA should address the key science issues concerning 
perchlorate in its preliminary regulatory determination and specified 
(1) a health reference level of 15 parts per billion of perchlorate in 
drinking water and (2) the rationale for EPA to support the conclusion 
that this health reference level would be protective of pregnant women 
and their fetuses as well as of infants and children. 

EPA Established a Reference Dose for Perchlorate but Subjected It to a 
More Limited Review Than the Agency's Standard IRIS Assessment Review 

In developing an IRIS assessment of perchlorate, EPA established a 
reference dose[Footnote 12] on the basis of the National Academies' 
recommendations, but subjected it to a more limited review than the 
agency's standard IRIS assessment review process.[Footnote 13] EPA's 
2002 draft IRIS assessment of perchlorate--from which EPA derived a 
drinking water equivalent level of 1 part per billion[Footnote 14]-- 
drew significant attention--including from such federal agencies as 
the Department of Defense, the Department of Energy, and the National 
Aeronautics and Space Administration, because of the implications such 
a level could have on their operations if EPA were to develop a 
drinking water regulation for perchlorate. According to a senior EPA 
official, the controversy that arose over the draft IRIS assessment of 
perchlorate "was like nothing I had ever seen or have seen since." As 
a result of the divergent views between EPA and the other federal 
agencies, the Administrator of OMB's Office of Information and 
Regulatory Affairs urged the four interested agencies to convene a 
National Academies panel to review the draft IRIS assessment. Convened 
in October 2003, the panel conducted this review and issued its report 
in January 2005.[Footnote 15] 

The National Academies 2005 perchlorate report made several key 
recommendations to EPA on the basis of a different study from those on 
which EPA had based its 2002 draft IRIS assessment on perchlorate. The 
National Academies' recommended reference dose was more than 20 times 
higher than the one proposed in EPA's draft IRIS assessment. EPA's 
final internal review of the revised IRIS assessment for perchlorate-- 
termed a consensus review--differed from the agency's usual consensus 
review process. For example, the scope of the internal review was 
limited in that the IRIS program did not seek input from consensus 
reviewers on the scientific basis for the assessment as it typically 
does; rather, it sought input only on the extent to which the science 
in the IRIS Summary was not inconsistent with the major conclusions of 
the National Academies' report. At least two EPA offices essentially 
opted out of the consensus review process because of this limitation, 
which was a significant departure from the usual IRIS consensus 

EPA Relied on an Estimate of the Relative Exposure to Perchlorate from 
Drinking Water and Food That It Derived from a Novel Analysis and Used 
a Nontraditional Method to Calculate the Relative Source Contribution: 

In developing its regulatory determination on perchlorate, EPA 
conducted a novel analysis to develop estimates of exposure to 
perchlorate for various subpopulations, which the agency subsequently 
used to calculate the relative source contribution--the allocated 
exposure to perchlorate from drinking water alone.[Footnote 16] 
Independent scientists who reviewed EPA's analysis noted that it had 
several limitations--in particular, uncertainties specific to the 
exposure estimate for pregnant women. Nonetheless, EPA relied on the 
exposure estimate for pregnant women to calculate the relative source 
contribution, stating that the National Academies had identified 
pregnant women and their fetuses as the most sensitive subpopulation. 
[Footnote 17] 

In calculating the relative source contribution, EPA used a 
nontraditional method--called the subtraction method[Footnote 18]-- 
that was less conservative than the approach it had used for its other 
completed regulatory determinations. While EPA identified some of the 
limitations of the exposure analysis in its preliminary regulatory 
determination notice for perchlorate, it did not discuss the effects 
of the limitations on EPA's exposure analysis. Although the agency's 
guidance for calculating the relative source contribution cautions 
against using the subtraction method in the absence of adequate data 
representative of at-risk populations--and EPA lacked data to estimate 
exposure to perchlorate for certain populations--the agency did not 
explain that the method it used to calculate the relative source 
contribution for perchlorate was the subtraction method or its 
reasoning for selecting this method. 

According to Key EPA Scientists, the Agency Mischaracterized Important 
Scientific Findings That Emerged from Its Novel Analysis of the 
Sensitivity of Various Age Groups to Perchlorate in Drinking Water: 

In early 2008, EPA used a physiologically based pharmacokinetic (PBPK) 
model[Footnote 19] to (1) evaluate the relative sensitivity of 
sensitive subpopulations to the health reference level the agency had 
developed based on pregnant women and their fetuses and (2) address 
concerns that some sensitive subpopulations, such as infants, exposed 
at the health reference level may receive concentrations of 
perchlorate above the reference dose. For its preliminary regulatory 
determination, the agency used the model in a novel way and, according 
to some key EPA scientists, mischaracterized the findings of the 
modeling analyses by selecting and presenting information in such a 
way as to support the agreed-upon conclusion that a health reference 
level of 15 parts per billion was protective of all sensitive 
subpopulations, including infants. 

While EPA's Office of Research and Development conducted numerous 
sensitivity analyses with the PBPK model, EPA presented the results of 
a PBPK analysis in its October 2008 preliminary regulatory 
determination for perchlorate to support its conclusion that a health 
reference level of 15 parts per billion was protective of all 
sensitive subpopulations, including infants, and stated that using the 
model in this way could reduce some of the uncertainty regarding the 
sensitivities of subpopulations other than pregnant women. However, 
Office of Research and Development officials disagreed with the way 
EPA presented the information in its preliminary regulatory 
determination notice, saying the agency did not sufficiently explain 
the uncertainties and limitations of the analysis, presenting the 
information more conclusively than was appropriate. 

Further, the table EPA published in the preliminary regulatory 
determination notice presenting the results of the PBPK analysis 
included data that may not be consistent with EPA's conclusion that a 
health reference level of 15 parts per billion was protective of all 
subpopulations. That is, the table provided sufficient data for 
informed readers of the preliminary determination to calculate that 
infants and young children could be exposed to doses of perchlorate at 
levels as high as 5.5 times greater than the reference dose, 
supporting the concern that infants and young children may, in fact, 
be more vulnerable to perchlorate exposure. While EPA's regulatory 
determination notice stated that the modeled exposure exceeds the 
reference dose for some subpopulations, the agency was not explicit 
about the extent to which the reference dose is exceeded--as 
calculated above--and did not explain the implications of this result 
on its conclusion that the health reference level of 15 parts per 
billion is protective of all subpopulations. In providing comments on 
the draft notice to the Office of Water, an Office of Research and 
Development scientist noted that the agency's failure to present a 
comparison of the estimated daily exposure with the reference dose 
constituted a "serious omission," and characterized the infants' 
estimated exposure as "substantially higher" than the reference dose. 

EPA's limited presentation of the PBPK analyses conducted by the 
Office of Research and Development in its preliminary regulatory 
determination notice validated the concern expressed at the time by 
Office of Research and Development scientists who conducted the 
analyses: that individual analyses could be used out of context in a 
way that could be misleading. Specifically, an Office of Research and 
Development official stated in September 2008 that while his office 
and the Office of Water had developed careful and sophisticated PBPK 
analyses to support the agency's preliminary regulatory determination, 
"the use of these science results in [the] draft regulatory 
determination is seriously flawed and misleading." As a result, Office 
of Research and Development officials and scientists that conducted 
the analyses concluded that the PBPK analysis done by the office did 
not support the draft preliminary regulatory determination's suggested 
health reference level of 15 parts per billion as being health 
protective for all sensitive subpopulations of concern to EPA. 

EPA's Independence in Developing and Communicating Its Scientific 
Findings Was Limited by Its Acceptance of External Input on the 
Preliminary Determination Notice: 

Compounding scientists' concerns about the mischaracterization and 
lack of transparency regarding relevant scientific analyses, key 
language in EPA's preliminary regulatory determination notice appears 
to have been drafted by OMB rather than EPA. In working to finalize 
the preliminary regulatory determination notice, EPA's Office of Water 
worked with OMB, whose clearance of the notice was required per EPA's 
policy implementing Executive Order 12866 before the Office of Water 
could provide it to the EPA Administrator for review, approval, and 
publication in the Federal Register.[Footnote 20] According to the 
Office of Water, in four iterations of review, OMB sent EPA a 
substantial number of comments on the notice; in response, EPA 
"clarified its description of the supporting analysis and strengthened 
the rationale for the determination." The following example highlights 
OMB's role in reviewing and approving the specific wording of EPA's 
scientific analyses regarding perchlorate exposure in infants and 

Text EPA provided to OMB: "Because infants and children eat and drink 
more on a per body weight basis than adults, eating a normal diet and 
drinking water with 15 [micrograms per liter] of perchlorate is likely 
to result in exposure that is greater than the reference dose in these 

Revised text provided to EPA by OMB: "Because infants and children eat 
and drink more on a per body weight basis than adults, eating a normal 
diet and drinking water with 15 [micrograms per liter] of perchlorate 
may result in exposure that is greater than the reference dose in 
these groups." 

By changing three words, OMB downplayed EPA's characterization of the 
health risks of perchlorate exposure. Importantly, the EPA scientist 
who wrote the text provided to OMB noted to EPA reviewers--before it 
was sent to OMB in August 2008--that the PBPK model actually showed 
exposures at levels "much higher" than the reference dose, but also 
said that he believed describing the exposure scenario as "likely" was 
the strongest characterization that might be retained through OMB 
review. In addition, in September 2008, during its review of the draft 
preliminary determination notice and before clearing it for 
publication, OMB reminded EPA that it expected the notice to "state a 
clear conclusion that the HRL [health reference level] is protective 
of all subpopulations, as agreed to in the August framework"--and 
accordingly, this conclusion appeared in the agency's October 2008 
preliminary determination notice.[Footnote 21] 

EPA's Response to Our Recommendations Does Not Appear to Acknowledge 
the Scope and Significance of the Implementation Limitations We 

We provided a draft of this report to the Administrator of EPA for 
review and comment. In commenting on the draft report, EPA agreed with 
2 of the 17 recommendations we made to improve its implementation of 
the Safe Drinking Water Act. Specifically, EPA agreed with our 
recommendations regarding its drinking water health advisories, 
stating that it would evaluate their utility and determine whether and 
how to revise the advisories to better serve states, localities, 
public water systems, and the public. However, EPA did not agree to 
implement the remaining 15 recommendations we made, including an 
overarching recommendation that EPA develop policies or guidance that 
clearly articulate the agency's interpretation of the Safe Drinking 
Water Act's broad statutory criteria--as well as eight additional 
recommendations identifying specific components of this guidance and 
calling for review of the draft guidance by one of EPA's independent 
advisory committees and the establishment of an internal review 
mechanism to help ensure the determinations are consistent with the 
guidance. Another key recommendation with which EPA disagreed was for 
EPA to include in the public record OMB's and other federal agencies' 
comments on and revisions to regulatory determination notices and 
support documents to improve transparency and help EPA ensure that it 
maintains the fairness and openness of its operations. 

We made these recommendations to support the development of regulatory 
determinations that are transparent, clear, and consistent and that 
follow applicable agency policy. However, EPA said it believed that 
establishing policies or guidance for regulatory determinations was 
not "practicable" because of the many combinations of health effects 
factors and potential ranges of frequencies and levels of contaminants 
measured in drinking water. We do not believe that the existence of 
variables or complexities is a basis for not developing guidance for 
EPA staff to implement the statutory requirements for regulatory 
determinations. In fact, the complexities cited would argue for, 
rather than against, the need to develop guidance for staff on 
applying the criteria. EPA also did not agree with these 
recommendations on the basis that policies or guidance could "inhibit 
its ability to continually improve its actions." This perspective 
suggests that guidance per se lacks flexibility. We do not agree that 
guidance and flexibility are incompatible or that developing guidance 
would inhibit EPA's ability to improve its actions. Rather, 
flexibility can and should be incorporated into guidance by 
establishing parameters or options for areas in which flexibility is 
deemed appropriate. 

Moreover, consistency and accountability are lacking in this important 
program because EPA has not developed guidance on the application of 
the broad statutory criteria, which are susceptible to varying 
interpretations. In its comments, EPA highlighted that, under these 
criteria, ultimately it is the Administrator's judgment as to whether 
regulation of a contaminant in drinking water presents a meaningful 
opportunity for health risk reduction, after considering the 
information presented by agency staff. As stated in our report, the 
statutory criteria are so broadly stated that they could potentially 
be interpreted so as to lead to regulating all the contaminants on the 
candidate list, some of them, or none of them. It is precisely for 
these reasons that we believe it is essential for the staff to have 
sufficient guidance on applying the broad criteria consistently and 
transparently so that the Administrator's judgment can be based on 
sound and consistent information. Without such guidance, the basis for 
EPA's determinations and the quality of the documentation the staff 
use to support them can fluctuate over time as a result of, among 
other reasons, changes in agency leadership and staff. In addition, 
regarding our recommendation that EPA provide in the public record 
OMB's and other federal agencies' comments on and revisions to 
regulatory determination documents, EPA's position is that unless 
required by law, it is not a good policy because, among other things, 
the documents may be confusing to the public and undermine the 
ultimate policy choice. We disagree and believe that to improve 
transparency of these determinations, which are by law committed to 
the Administrator's judgment, EPA should consistently make these 
documents available in the public record, regardless of whether there 
is a specific legal requirement for disclosure. 

In large measure, EPA's response to our recommendations essentially 
endorses conducting business as usual; a response that does not seem 
to acknowledge the scope and significance of the implementation 
limitations we identified. We are concerned that EPA's lack of 
responsiveness to our recommendations may reflect a misplaced reliance 
on the Office of Water to independently improve the management of this 
important program in the absence of (1) regulations, policies, or 
guidance that we believe are needed to provide a framework for current 
and future staff to apply in identifying and evaluating contaminants 
for regulation; (2) the identification of clear and specific actions 
needed to address our recommendations; and (3) an internal review 
mechanism to ensure identified actions are implemented effectively. We 
believe that EPA needs to adopt all of the recommendations in our 
report to better assure the public of safe drinking water. 

Madam Chairman Boxer, Ranking Member Inhofe, and Members of the 
Committee, this concludes our prepared statement. I would be happy to 
respond to any questions that you or other Members of the Committee 
may have. 

Contacts and Acknowledgment: 

For further information about this testimony, please contact me at 
(202) 512-3841. Christine Fishkin, Jamie Meuwissen, Elizabeth 
Beardsley, Kiki Theodoropoulos, and Michael Derr also made key 
contributions to this statement. 

[End of section] 


[1] GAO, Safe Drinking Water Act: EPA Should Improve Implementation of 
Requirements on Whether to Regulate Additional Contaminants, 
[hyperlink,] (Washington, D.C.: 
May 27, 2011). 

[2] The 1996 amendments require that EPA identify and publish a list 
every 5 years of unregulated contaminants that may require regulation; 
the list is called the contaminant candidate list. 

[3] The health reference level is the estimated level of exposure to a 
contaminant in drinking water below which adverse health effects are 
not likely. 

[4] EPA did not disclose that the data presented were not sufficiently 
sensitive to detect occurrence at the agency's health reference level. 

[5] In this testimony, as in our report, we refer to Federal Register 
notices regarding EPA's regulatory determinations (notices) and EPA's 
regulatory determination support documents individually and 
collectively, as appropriate. When referring to these documents 
collectively, we use the term "regulatory determination documents." 

[6] See GAO, Chemical Assessments: Low Productivity and New 
Interagency Review Process Limit the Usefulness and Credibility of 
EPA's Integrated Risk Information System, [hyperlink,] (Washington, D.C.: Mar. 7, 

[7] In January 2009 we added transforming EPA's processes for 
assessing and controlling toxic chemicals as a high-risk area in our 
report--updated in February 2011--on governmentwide high-risk areas 
requiring increased attention by executive agencies and Congress. See 
GAO, High-Risk Series: An Update, [hyperlink,] (Washington, D.C.: January 
2009); and High Risk Series: An Update, [hyperlink,] (Washington, D.C.: February 

[8] IRIS assessments provide EPA's toxicity assessments of 
contaminants that may cause cancer and those that may cause 
neurological or other noncancer effects, or both. EPA uses IRIS or 
comparable toxicity assessments to develop health reference levels for 
the drinking water contaminants. 

[9] The Perchlorate Interagency Working Group includes officials from 
the Office of Management and Budget (OMB) and the Office of Science 
and Technology Policy, both part of the Executive Office of the 
President; Department of Defense; National Aeronautics and Space 
Administration; Department of Energy; the Department of Health and 
Human Services' Food and Drug Administration and the Agency for Toxic 
Substances and Disease Registry; Department of Agriculture; and 
Department of the Interior. 

[10] The Council on Environmental Quality, which is part of the 
Executive Office of the President, coordinates federal environmental 
efforts in the development of environmental policies and initiatives. 

[11] According to an EPA official, the agreement was documented in an 
unattributed two-page white paper and faxed to EPA from the Council on 
Environmental Quality in early August 2008; EPA made some editorial 
changes to the document but did not alter the substance of the 

[12] A reference dose is an estimate of the total daily oral exposure 
to a contaminant--for example, from food and water--that is not likely 
to cause "appreciable risk of deleterious effects during a lifetime." 
A reference dose is a key component of the calculation EPA uses to 
derive a health reference level for drinking water contaminants. 

[13] The National Academies consists of four private, nonprofit 
organizations that advise the federal government on scientific and 
technical matters: the National Academy of Sciences, National Academy 
of Engineering, Institute of Medicine, and National Research Council. 

[14] A drinking water equivalent level represents the estimated 
exposure to a contaminant that is assumed to be protective for 
noncarcinogenic health effects during a lifetime of exposure. EPA 
calculated this drinking water equivalent level using the reference 
dose that EPA proposed in its 2002 draft IRIS assessment and the 
agency's default assumptions for adult weight and daily drinking water 

[15] National Academies, Health Implications of Perchlorate Ingestion 
(Washington, D.C., 2005). 

[16] The relative source contribution is an allocation of the 
estimated oral exposure to the contaminant from drinking water alone; 
it has a significant impact on the health reference level that the 
agency derives for contaminants with noncancer adverse health effects. 

[17] The 2005 National Academies report on perchlorate contained 
varying characterizations of sensitive subpopulations, sometimes 
referring to pregnant women and their fetuses alone as the most 
sensitive subpopulation and other times including infants in this 
designation. In addition, the National Academies identified developing 
children as a sensitive population and people with compromised thyroid 
function and people who are iodide-deficient as potentially sensitive 

[18] The subtraction method allocates the entire reference dose to the 
known sources of exposure by subtracting the known nontarget sources 
of exposure and allocating the remainder of the reference dose to the 
target--in this case, drinking water--even in cases where the total 
estimated exposure is less than the reference dose. This method has 
the effect of removing any cushion between the existing exposure 
levels and the reference dose. 

[19] PBPK models are complex and involve numerous underlying 
assumptions that are imbedded in mathematical representations of the 
processes associated with how a contaminant behaves within, and is 
eliminated from, the body. 

[20] The objectives of this executive order are to enhance planning 
and coordination with respect to both new and existing regulations; to 
reaffirm the primacy of federal agencies in the regulatory decision- 
making process; to restore the integrity and legitimacy of regulatory 
review and oversight; and to make the process more accessible and open 
to the public. 

[21] According to an EPA official, "August framework" refers to the 
agreement that was faxed to EPA from the Council on Environmental 
Quality that included this conclusion as a key component of the 
rationale EPA and other federal agencies agreed to in August 2008. 

[End of section] 

GAO's Mission: 

The Government Accountability Office, the audit, evaluation and 
investigative arm of Congress, exists to support Congress in meeting 
its constitutional responsibilities and to help improve the performance 
and accountability of the federal government for the American people. 
GAO examines the use of public funds; evaluates federal programs and 
policies; and provides analyses, recommendations, and other assistance 
to help Congress make informed oversight, policy, and funding 
decisions. GAO's commitment to good government is reflected in its core 
values of accountability, integrity, and reliability. 

Obtaining Copies of GAO Reports and Testimony: 

The fastest and easiest way to obtain copies of GAO documents at no 
cost is through GAO's Web site [hyperlink,]. Each 
weekday, GAO posts newly released reports, testimony, and 
correspondence on its Web site. To have GAO e-mail you a list of newly 
posted products every afternoon, go to [hyperlink,] 
and select "E-mail Updates." 

Order by Phone: 

The price of each GAO publication reflects GAO’s actual cost of
production and distribution and depends on the number of pages in the
publication and whether the publication is printed in color or black and
white. Pricing and ordering information is posted on GAO’s Web site, 

Place orders by calling (202) 512-6000, toll free (866) 801-7077, or
TDD (202) 512-2537. 

Orders may be paid for using American Express, Discover Card,
MasterCard, Visa, check, or money order. Call for additional 

To Report Fraud, Waste, and Abuse in Federal Programs: 


Web site: [hyperlink,]: 
Automated answering system: (800) 424-5454 or (202) 512-7470: 

Congressional Relations: 

Ralph Dawn, Managing Director, 
(202) 512-4400: 
U.S. Government Accountability Office: 
441 G Street NW, Room 7125: 
Washington, D.C. 20548: 

Public Affairs: 

Chuck Young, Managing Director, 
(202) 512-4800: 
U.S. Government Accountability Office: 
441 G Street NW, Room 7149: 
Washington, D.C. 20548: