United States Government Accountability Office

GAO Testimony

Before the Subcommittee on Oversight 

and Investigations, Committee on Energy 

and Commerce, House of Representatives

EPA SCIENCE

New Assessment Process 

Further Limits the 

Credibility and Timeliness 

of EPA's Assessments of 

Toxic Chemicals 

Statement of John B. Stephenson, Director 

Natural Resources and Environment 

For Release on Delivery

Expected at 10:00 a.m. EDT 

Thursday, September 18, 2008 

 

GAO-08-1168T 
What GAO Found

United States Government Accountability Office

Why GAO Did This Study

Highlights

Accountability Integrity Reliability

September 18, 2008

EPA SCIENCE

New Assessment Process Further Limits the 

Credibility and Timeliness of EPA's Assessments of 

Highlights of GAO-08-1168T, testimony Toxic Chemicals

before the Subcommittee on Oversight 

and Investigations, Committee on Energy 

and Commerce, House of Representatives

The Environmental Protection 

Agency’s (EPA) Integrated Risk 

Information System (IRIS) contains 

EPA’s scientific position on the 

potential human health effects of

exposure to more than 540 

chemicals. Toxicity assessments in 

the IRIS database constitute the 

first two critical steps of the risk

assessment process, which in turn, 

provides the foundation for risk 

management decisions. Thus, IRIS

is a critical component of EPA’s 

capacity to support scientifically 

sound environmental decisions, 

policies, and regulations. 

This testimony discusses (1) 

highlights of GAO’s March 2008

report, Chemical Assessments: 

Low Productivity and New 

Interagency Review Process Limit 

the Usefulness and Credibility of 

EPA’s Integrated Risk Information 

System; (2) key aspects of EPA’s 

revised IRIS assessment process, 

released on April 10, 2008; and (3) 

progress EPA has made in 

completing assessments in fiscal 

year 2008. For the March 2008

report, GAO reviewed and analyzed 

EPA data and interviewed officials 

at relevant agencies, including the

Office of Management and Budget

(OMB). For this testimony, GAO 

supplemented the prior audit work 

with a review of EPA’s revised IRIS

assessment process announced on 

April 10, 2008. We also updated

our information on EPA’s 

assessment productivity through 

September 12, 2008.

In March 2008, GAO concluded that the IRIS database was at serious risk of 

becoming obsolete because EPA had not been able to complete timely, 

credible assessments or decrease its backlog of 70 ongoing assessments—a 

total of 4 were completed in fiscal years 2006 and 2007. In addition, 

assessment process changes EPA had recently made, as well as other changes 

EPA was considering at the time of GAO’s review, would further reduce the 

credibility and timeliness of IRIS assessments. We concluded the following: 

• EPA’s efforts to finalize assessments have been thwarted by a 

combination of factors, including two new OMB-required reviews of IRIS 

assessments by OMB and other federal agencies and by EPA management 

decisions, such as delaying some assessments to await new research. 

• The two new OMB/interagency reviews of draft assessments involve other 

federal agencies in EPA’s IRIS assessment process in a manner that limits 

the credibility of IRIS assessments and hinders EPA’s ability to manage 

them. For example, the OMB/interagency reviews lack transparency, and 

OMB required EPA to terminate five assessments EPA had initiated to 

help it implement the Clean Air Act. 

• The changes to the IRIS assessment process that EPA was considering, 

but had not yet issued at the time of our review, would have added to the 

already unacceptable level of delays in completing IRIS assessments and 

further limited the credibility of the assessments. 

EPA issued its revised IRIS assessment process in April 2008. The new 

process is largely the same as the draft GAO evaluated and does not respond 

to the recommendations in GAO’s March 2008 report. Moreover, some key 

changes are likely to further exacerbate the productivity and credibility 

concerns GAO identified. For example, while the draft process would have 

made comments from other federal agencies on IRIS assessments part of the 

public record, EPA’s new process defines such comments as “deliberative” 

and excludes them from the public record. GAO continues to believe that it is 

critical that input from all parties—particularly agencies that may be affected

by the outcome of IRIS assessments—be publicly available. In addition, the 

estimated time frames under the new process, especially for chemicals of key 

concern, will likely perpetuate the cycle of delays to which the majority of 

ongoing assessments have been subject. Instead of streamlining the process,

as GAO recommended, EPA has institutionalized a process that from the 

outset is estimated to take 6 to 8 years. This is problematic because of the 

substantial rework such cases often require to take into account changing 

science and methodologies. 

EPA’s progress in completing assessments continues to be slow—only four 

assessments have been completed in fiscal year 2008. Further, these

assessments cover a group of four related chemicals that were processed and

peer reviewed together but finalized individually. Little or no progress has 

been made on assessments of chemicals highlighted in our report, including 

naphthalene, formaldehyde, and trichloroethylene (TCE). 

To view the full product, including the scope 

and methodology, click on GAO-08-1168T. 

For more information, contact John

Stephenson at (202) 512-3841 or

stephensonj@gao.gov. 
Mr. Chairman and Members of the Subcommittee: 

I am pleased to be here today to discuss issues associated with the 

credibility and usefulness of the Environmental Protection Agency’s (EPA) 

Integrated Risk Information System (IRIS) as the Subcommittee examines 

scientific integrity at the agency. Containing EPA’s scientific position on 

the potential human health effects that may result from exposure to more 

than 540 chemicals in the environment, IRIS is one of the most significant 

tools that EPA has developed to effectively support its mission of 

protecting people and the environment from harmful chemical exposures. 

IRIS is therefore a critical component of EPA’s capacity to support 

scientifically sound risk management decisions, policies, and regulations.

As shown in figure 1, the toxicity assessments in the IRIS database fulfill 

the first two critical steps of the National Academies’1

 four-step risk 

assessment process—providing hazard identification and quantitative 

dose-response assessments. IRIS information can then be used with the 

results of exposure assessments (typically conducted by EPA’s program or 

regional offices) to provide an overall characterization of the public health

risks for a given chemical in a given situation. The development of health 

risk assessments is thus directly dependent on the development of toxicity

assessments such as those developed in the IRIS program. 

 1

The National Academies comprises four organizations: the National Academy of Sciences, 

the National Academy of Engineering, the Institute of Medicine, and the National Research

Council. 

Page 1 GAO-08-1168T 
Figure 1: National Academies’ Risk Assessment and Risk Management Model Used

by EPA 

Risk assessment

IRIS toxicity assessment:

1. Hazard identification

2. Dose-response

 assessments

3. Exposure assessment

Source: National Academies.

Risk management

Development of regulatory

options

Evaluation of public health,

economic, social, and

political consequences of

regulatory options

Agency decisions 

and actions

 4. Risk

characterization

Under the National Academies’ risk assessment and risk management 

paradigm, policy considerations become relevant in the risk management 

phase, which occurs after the risk assessment phase. With risk assessment 

information, decision makers can make informed risk management 

decisions on how to protect public health, reflecting other important data 

and considerations, such as the costs and benefits of mitigating identified

risks, the technological feasibility of managing risks, and the concerns of 

various stakeholders. Examples of risk management decisions include 

deciding how much of a chemical a company may discharge into a river, 

determining the extent to which a hazardous waste site must be cleaned 

up, and setting allowable levels of contamination in drinking water. 

Thus, although IRIS assessments are not regulatory in nature, the 

quantitative IRIS values are likely to influence many risk management 

decisions and serve as a basis for regulatory consideration. However, 

EPA’s productivity in finalizing IRIS assessments is poor, and EPA has a 

significant backlog of incomplete IRIS assessments and a growing number 

of outdated assessments. Importantly, EPA has not been able to complete

assessments of key chemicals of concern to public health, including 

dioxin, formaldehyde, trichloroethylene (TCE), naphthalene, and 

tetrachloroethylene (perc) (see app. I). 

Page 2 GAO-08-1168T 
In this context, my testimony today discusses (1) highlights of our March 

2008 report, Chemical Assessments: Low Productivity and New 

Interagency Review Process Limit the Usefulness and Credibility of EPA’s 

Integrated Risk Information System,2

 (2) key aspects of EPA’s revised IRIS 

assessment process, released on April 10, 2008,3

 and (3) progress EPA has 

made in completing assessments in fiscal year 2008. For our March 2008 

report, we examined the outcome of steps EPA has taken to ensure that 

IRIS contains current, credible chemical risk information; to address the 

backlog of ongoing assessments; and to respond to new requirements from 

the Office of Management and Budget (OMB). We also examined the 

potential effects of planned changes to the IRIS assessment process on 

EPA’s ability to ensure that IRIS provides current, credible risk 

information. In conducting our work, we obtained and analyzed 

information on EPA’s productivity and the resources provided to the 

program for fiscal years 2000 through 2007, user needs, and EPA’s 

assessment completion goals. We also interviewed EPA’s National Center 

for Environmental Assessment officials who manage the IRIS assessment 

program; officials from other EPA program offices and federal science and 

health agencies involved in the IRIS assessment process; and officials from 

the Department of Defense, the Department of Energy (DOE), the National

Aeronautics and Space Administration (NASA), and OMB. We have 

supplemented our report with a review of the IRIS assessment process 

that EPA released on April 10, 2008, and with updated information on the 

status of EPA’s IRIS assessments. We conducted this work from 

September 11 to September 18, 2008, 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. 

 2

GAO-08-440 (Washington, D.C.: Mar. 7, 2008).

3

See Toxic Chemicals: EPA’s New Assessment Process Will Increase Challenges EPA 

Faces in Evaluating and Regulating Chemicals, GAO-08-743T (Washington, D.C.: Apr. 29, 

2008) and Chemical Assessments: EPA’s New Assessment Process Will Further Limit the 

Productivity and Credibility of Its Integrated Risk Information System, GAO-08-810T 

(Washington, D.C.: May 21, 2008). 

Page 3 GAO-08-1168T 
IRIS was created in 1985 to help EPA develop consensus opinions within 

the agency about the health effects of chronic exposure to chemicals. Its 

importance has increased over time as EPA program offices and the states 

have increasingly relied on IRIS information in making environmental 

protection decisions. Currently, the IRIS database contains assessments of 

more than 540 chemicals. According to EPA, national and international 

users access the IRIS database approximately 9 million times a year. EPA’s 

Assistant Administrator for the Office of Research and Development has 

described IRIS as the premier national and international source for 

qualitative and quantitative chemical risk information; other federal 

agencies have noted that IRIS data are widely accepted by all levels of 

government across the country for application of public health policy, 

providing benefits such as uniform, standardized methods for toxicology 

testing and risk assessment, as well as uniform toxicity values. Similarly, a 

private-sector risk assessment expert has stated that the IRIS database has 

become the most important source of regulatory toxicity values for use 

across EPA’s programs and is also widely used across state programs and 

internationally. 

Background 

Historically and currently, the focus of IRIS toxicity assessments has been 

on the potential health effects of long-term (chronic) exposure to 

chemicals. According to OMB, EPA is the only federal agency that 

develops qualitative and quantitative assessments of both cancer and 

noncancer risks of exposure to chemicals, and EPA does so largely under 

the IRIS program. Other federal agencies develop quantitative estimates of 

noncancer effects or qualitative cancer assessments of exposure to 

chemicals in the environment. While these latter assessments provide 

information on the effects of long-term exposures to chemicals, they 

provide only qualitative assessments of cancer risks (known human 

carcinogen, likely human carcinogen, etc.) and not quantitative estimates 

of cancer potency, which are required to conduct quantitative risk 

assessments.

EPA’s IRIS assessment process has undergone a number of formal and 

informal changes during the past several years. While the process used to 

develop IRIS chemical assessments includes numerous individual steps, or 

activities, major assessment steps include (1) a review of the scientific 

literature; (2) preparation of a draft IRIS assessment; (3) internal EPA 

reviews of draft assessments; (4) two OMB/interagency reviews, managed 

by OMB, that provide input from OMB as well as from other federal 

agencies, including those that may be affected by the IRIS assessments if 

they lead to regulatory or other actions; (5) an independent peer review 

Page 4 GAO-08-1168T 
conducted by a panel of experts; and (6) the completion of a final 

assessment that is posted to the IRIS Web site. 

Unlike many other EPA programs that have statutory requirements, 

including specific time frames for completing mandated tasks, the IRIS 

program is not subject to statutory requirements or time frames. In 

contrast, the Department of Human Health and Services’ Agency for Toxic 

Substances and Disease Registry (ATSDR), which develops quantitative 

estimates of the noncancer effects of exposures to chemicals in the 

environment, is statutorily required to complete its assessments within 

certain time frames. 

The IRIS database is at serious risk of becoming obsolete because the 

agency has not been able to routinely complete timely, credible 

assessments or decrease a backlog of 70 ongoing assessments. 

Specifically, although EPA has taken important steps to improve the IRIS 

program and productivity since 2000 and has developed a number of draft 

assessments for external review, its efforts to finalize the assessments

have been thwarted by a combination of factors including the imposition 

of external requirements, the growing complexity and scope of risk 

assessments, and certain EPA management decisions. In addition, the 

changes to the IRIS assessment process that EPA was considering at the

time of our review would have added to the already unacceptable level of 

delays in completing IRIS assessments and further limited the credibility 

of the assessments. 

Findings and 

Recommendations 

from Our March 2008 

Report on the 

Credibility and 

Usefulness of EPA’s 

Integrated Risk 

Information System 

Page 5 GAO-08-1168T 
EPA has taken a number of steps to help ensure that IRIS contains current, 

credible chemical risk information; to address its backlog of ongoing 

assessments; and to respond to new OMB requirements. However, to date, 

these changes—including increasing funding, centralizing staff conducting 

assessments, and revising the assessment process—have not enabled EPA 

to routinely complete credible IRIS assessments or decrease the backlog.

That is, although EPA sent 32 draft assessments for external review in 

fiscal years 2006 and 2007, the agency finalized only 4 IRIS assessments 

during this time (see fig. 2). 

EPA’s Efforts to Improve 

the IRIS Assessment 

Program Have Not 

Produced the Desired 

Results 

Figure 2: Number of Completed IRIS Assessments, Draft Assessments to OMB, and 

IRIS Staff in Full-Time Equivalents, Fiscal Years 2000-2007 

0

5

10

15

20

25

30

35

40

2000 2001 2002 2003 2004 2005 2006 2007

Source: GAO analysis of EPA data.

Fiscal year

IRIS staff levels in full-time equivalents

IRIS assessments completed

Draft IRIS assessments to OMB for OMB/interagency review

(Year OMB/interagency

review initiated)

Several key factors have contributed to EPA’s inability to achieve a level

of productivity that is needed to sustain the IRIS program and database:

new OMB-required reviews of IRIS draft assessments by OMB and other 

federal agencies; the growing complexity and scope of risk assessments; 

certain EPA management decisions and issues, including delaying 

completion of some assessments to await new research or to develop

Page 6 GAO-08-1168T 
enhanced analyses of uncertainty in the assessments; and the 

compounding effect of delays. Regarding the last factor, even a single 

delay in the assessment process can lead to the need to essentially repeat 

the assessment process to take into account changes in science and

methodologies. 

A variety of delays have impacted the majority of the 70 assessments being 

conducted as of December 2007—48 had been in process for more than 5 

years, and 12 of those for more than 9 years. These time frames are 

problematic because of the substantial rework such cases often require to

take into account changing science and methodologies before they can be 

completed. For example, EPA’s assessment of the cancer risks stemming 

from exposure to naphthalene—a chemical used in jet fuel and in the 

production of widely used commercial products such as moth balls, dyes, 

insecticides, and plasticizers—was nearing completion in 2006. However, 

prior to finalizing this assessment, which had been ongoing for over 4 

years, EPA decided that the existing noncancer assessment had become 

outdated and essentially restarted the assessment to include both cancer 

and noncancer effects. As a result, 6 years after the naphthalene 

assessment began, it is now back at the drafting stage. The assessment 

now will need to reflect relevant research completed since the draft 

underwent initial external peer review in 2004, and it will have to undergo 

all of the IRIS assessment steps again, including the additional internal and 

external reviews that are now required (see app. I). 

Further, because EPA staff time continues to be dedicated to completing 

assessments in the backlog, EPA’s ability to both keep the more than 540 

existing assessments up to date and initiate new assessments is limited. 

Importantly, EPA program offices and state and local entities have 

requested assessments of hundreds of chemicals not yet in IRIS, and EPA 

data as of 2003 indicated that the assessments of 287 chemicals in the 

database could be outdated—that is, new information could change the 

risk estimates currently in IRIS or enable EPA to develop additional risk 

estimates for chemicals in the database (for example, developing a cancer 

potency estimate for assessments with only noncancer estimates). In 

addition, because EPA’s 2003 data are now more than 4 years old, it is 

likely that more assessments may be outdated now. 

The consequences of not having current, credible IRIS information can be

significant. EPA’s inability to complete its assessment of formaldehyde, 

which the agency initiated in 1997 to update information already in IRIS on

the chemical, has had a significant impact on EPA’s air toxics program. 

Although in 2003 and 2004, the National Cancer Institute and the National

Page 7 GAO-08-1168T 
Institute of Occupational Safety and Health (NIOSH) had released updates 

to major epidemiological studies of industrial workers that showed a 

relationship between formaldehyde and certain cancers, including 

leukemia, EPA did not move forward to finalize an IRIS assessment 

incorporating these important data. Instead, EPA opted to await the 

results of another update to the National Cancer Institute study. While this

additional research was originally estimated to take, at most, 18 months to 

complete, at the time of our report (more than 3 years later) the update 

was not complete. In the absence of this information, EPA’s Office of Air 

and Radiation decided to use risk information developed by an industryfunded organization—the CIIT Centers for Health Research—for a 

national emissions standard. This decision was a factor in EPA’s 

exempting certain facilities with formaldehyde emissions from the 

national emissions standard. The CIIT risk estimate indicates

formaldehyde’s potency at about 2,400 times lower than the estimate in 

IRIS that was being re-evaluated and that did not yet consider the 2003 and 

2004 National Cancer Institute and NIOSH epidemiological studies. 

According to an EPA official, an IRIS cancer risk factor based on the 2003

and 2004 National Cancer Institute and NIOSH studies would likely be 

close to the current IRIS assessment, which EPA has been re-evaluating 

since 1997. The discrepancy between these two risk estimates raises 

concerns about whether the public health is adequately protected in the 

absence of current IRIS information. For example, in 1999, EPA published 

a national assessment that provided information about the types and 

amounts of air toxics to which people are exposed. The assessment, which 

also used the CIIT risk estimate for formaldehyde, concluded, for example, 

that formaldehyde did not contribute significantly to the overall cancer 

risk in the state of New Jersey. However, in carrying out its own risk 

assessment on formaldehyde, the New Jersey Department of 

Environmental Protection opted to use the risk information that is 

currently in IRIS (dating back to 1991) and found that the contribution 

from formaldehyde to overall cancer risk in New Jersey is quite significant, 

second only to diesel particulate matter. (App. I provides additional 

information on EPA’s IRIS assessment for formaldehyde.) 

One of the factors that has contributed to EPA’s inability to complete 

assessments in a timely manner—the new OMB-directed OMB/interagency

review process—also limits the credibility of the assessments because it

lacks transparency. Specifically, neither the comments nor the changes 

EPA makes to the scientific IRIS assessments in response to the 

comments made by OMB and other federal agencies, including those 

whose workload and resource levels could be affected by the assessments, 

are disclosed. In addition, the OMB/interagency reviews have hindered 

Page 8 GAO-08-1168T 
EPA’s ability to independently manage its IRIS assessments. For example, 

without communicating its rationale for doing so, OMB directed EPA to 

terminate five IRIS assessments that for the first time addressed acute, 

rather than chronic exposure—even though EPA initiated this type of 

assessment to help it implement the Clean Air Act.

The Expansion of 

Agencies’ Roles in IRIS 

Assessments That EPA 

Was Considering at the 

Time of Our Review Would 

Have Caused Further 

Delays and Limited the 

Assessments’ Credibility 

For our March 2008 report, we reviewed the additional assessment 

process changes EPA was planning and concluded that they would likely 

exacerbate delays in completing IRIS assessments and further affect their

credibility. Specifically, despite the OMB/interagency review process that 

OMB required EPA to incorporate into the IRIS assessment process in 

2005, certain federal agencies continued to believe they should have

greater and more formal roles in EPA’s development of IRIS assessments. 

Consequently, EPA had been working for several years to establish a 

formal IRIS assessment process that would further expand the role of 

federal agencies in the process—including agencies such as DOD, which 

could be affected by the outcome of IRIS assessments. For example, some 

of these agencies and their contractors could face increased cleanup costs 

and other legal liabilities if EPA issued an IRIS assessment for a chemical

that resulted in a decision to regulate the chemical to protect the public. In

addition, the agencies could be required to, for example, redesign systems 

and processes to eliminate hazardous materials; develop material 

substitutes; and improve personal protective clothing, equipment, and 

procedures. Under the changes that EPA was planning at the time of our 

review, these potentially affected agencies would have the opportunity to 

be involved, or provide some form of input, at almost every step of EPA’s 

IRIS assessment process. Most significantly, the changes would have

provided federal agencies, including those facing potential regulatory 

liability, with several opportunities during the IRIS assessment process to 

subject particular chemicals of interest to additional process steps. These 

additional process steps, which would have lengthened assessment times 

considerably, include 

• giving federal agencies and the public 45 days to identify additional 

information on a chemical for EPA’s consideration in its assessment or to 

Page 9 GAO-08-1168T 
correct any errors on an additional assessment draft that would provide 

qualitative information;4

• giving potentially affected federal agencies 30 days to review the public 

comments EPA received and initiate a meeting with EPA if they want to 

discuss a particular set of comments; 

• allowing potentially affected federal agencies to have assessments 

suspended for up to 18 months to fill a data gap or eliminate an 

uncertainty factor that EPA plans to use in its assessment; and 

• allowing other federal agencies to weigh in on (1) the level of independent

peer review that would be sought (that is, whether the peer reviews would 

be conducted by EPA Science Advisory Board panels, National Academies’ 

panels, or panels organized by an EPA contractor); (2) the areas of 

scientific expertise needed on the panel; and (3) the scope of the peer 

reviews and the specific issues they would address. 

EPA estimated that assessments that undergo these additional process 

steps would take up to 6 years to complete. While it is important to ensure

that assessments consider the best science, EPA has acknowledged that 

waiting for new data can result in substantial harm to human health, 

safety, and the environment. Further, although coordination with other 

federal agencies about IRIS assessments could enhance their quality,5

increasing the role of agencies that may be affected by IRIS assessments in 

the process itself reduces the credibility of the assessments if that 

expanded role is not transparent. In this regard, while EPA’s proposed 

changes would have allowed for including federal agencies’ comments in 

the public record, the implementation of this proposal was delayed for a 

year, in part, because of OMB’s view that agencies’ comments about IRIS 

assessments represent internal executive branch communications that 

may not be made public—a view that is inconsistent with the principle of 

sound science, which relies on, among other things, transparency. (App. II 

and III provide flow charts of the IRIS process that was in place at the time 

 4

This represents an additional review of a new draft product and comment period that had 

not existed previously. As shown in app. II, the assessment process EPA used at the time of 

our review included publishing its annual IRIS assessment agenda in the Federal Register 

and soliciting relevant scientific information from the public. 

5

We recommended in our 2006 report on human health risk assessment that EPA 

consistently involve stakeholders as appropriate to the risk assessment. We made this 

recommendation in the context of improving the overall quality, consistency, and 

transparency of risk assessments. GAO, Human Health Risk Assessment: EPA Has Taken 

Steps to Strengthen Its Process, but Improvements Needed in Planning, Data

Development, and Training, GAO-06-595 (Washington, D.C.: May 31, 2006). 

Page 10 GAO-08-1168T 
of our review and EPA’s draft proposed process being considered at the 

time of our review, respectively). 

To address the productivity and credibility issues we identified, we 

recommended that the EPA Administrator require the Office of Research

and Development to re-evaluate its draft proposed changes to the IRIS 

assessment process in light of the issues raised in our report and ensure 

that any revised process, among other things, clearly defines and 

documents an IRIS assessment process that will enable the agency to 

develop the timely chemical risk information it needs to effectively 

conduct its mission. One of our recommendations—that EPA provide at

least 2 years’ notice of IRIS assessments that are planned—would, among 

other things, provide an efficient alternative to suspending assessments 

while waiting for new research because interested parties would have the 

opportunity to conduct research before assessments are started. 

In addition, we recommended that the EPA Administrator take steps to 

better ensure that EPA has the ability to develop transparent, credible IRIS

assessments—an ability that relies in large part on EPA’s independence in 

conducting these important assessments. Actions that are key to this 

ability include ensuring that EPA can (1) determine the types of 

assessments it needs to support EPA programs and (2) define the 

appropriate role of external federal agencies in EPA’s IRIS assessment 

process, and (3) manage an interagency review process in a manner that 

enhances the quality, transparency, timeliness, and credibility of IRIS 

assessments. In its February 21, 2008, letter providing comments on our 

draft report, EPA said it would consider each of our recommendations in

light of the new IRIS process the agency was developing. 

On April 10, 2008, EPA issued a revised IRIS assessment process, effective 

immediately. Overall, EPA’s revised process is not responsive to the 

recommendations made in our March 2008 report—it is largely the same 

as the draft proposed process we evaluated in our March 2008 report (see 

app. III and IV). Moreover, changes EPA did incorporate into the final 

process are likely to further exacerbate the productivity and credibility 

issues we identified in our report. 

• We recommended that EPA ensure that, among other things, any revised 

process clearly defines and documents a streamlined IRIS assessment

process that can be conducted within time frames that minimize the 

need for wasteful rework. 

Recommendations Made in 

Our March 2008 Report 

Key Aspects of the 

Revised IRIS 

Assessment Process 

Implemented in April 

2008 Which Is Not 

Responsive to Our 

Recommendations 

Page 11 GAO-08-1168T 
As discussed in our report, when assessments take longer than 2 years, 

they can become subject to substantial delays stemming from the need to 

redo key analyses to take into account changing science and assessment 

methodologies. However, EPA’s revised process institutionalizes a process 

that the agency estimates will take up to 6 years to complete. Further, the 

estimated time frames do not factor in the time for peer reviews 

conducted by the National Academies, which can take 2 years to plan and 

complete.6

 EPA typically uses reviews by the National Academies for 

highly controversial chemicals or complex assessments. Therefore, 

assessments of key chemicals of concern to public health that are 

reviewed by the National Academies are likely to take at least 8 years to 

complete. These time frames must also be considered in light of OMB’s 

view that health assessment values in IRIS are out of date if they are more 

than 10 years old and if new scientific information exists that could 

change the health assessment values. Thus, EPA’s new process 

institutionalizes time frames that could essentially require the agency to

start assessment updates as soon as 2 years after assessments are finalized 

in order to keep the IRIS database current. Such time frames are not 

consistent with our recommendation that EPA develop, clearly define, and 

document a streamlined IRIS process that can be conducted within time 

frames that minimize the need for wasteful rework. Further, the agency 

would need a significant increase in resources to support such an 

assessment cycle.

In addition, EPA had previously emphasized that, in suspending 

assessments to allow agencies to fill in data gaps, it would allow no more 

than 18 months to complete the studies and have them peer reviewed. 

However, under the new process, EPA states that it generally will allow no 

more than 18 months to complete the studies and have them peer 

reviewed. As we concluded in our report, we believe the ability to suspend 

assessments for up to 18 months would add to the already unacceptable 

level of delays in completing IRIS assessments. Further, we and several 

agency officials with whom we spoke believe that the time needed to plan, 

conduct, and complete research that would address significant data gaps,

and have it peer reviewed, would likely exceed 18 months. Therefore, the 

less rigid time frame EPA included in its new process could result in 

additional delays. 

 6

It is not clear whether the time frames exclude reviews conducted by EPA’s Science 

Advisory Board, which can also add considerably more time than the most basic level of 

peer review used by the IRIS program—panels organized by an EPA contractor. 

Page 12 GAO-08-1168T 
Finally, the new process expands the scope of one of the additional steps 

that initially was to apply only to chemicals of particular interest to federal 

agencies.7

 Specifically, under the draft process we reviewed, EPA would 

have provided an additional review and comment opportunity for federal 

agencies and the public for what EPA officials said would be a small group 

of chemicals. However, under EPA’s new process, this additional step has 

been added to the assessment process for all chemicals and, therefore, will 

add time to the already lengthy assessments of all chemicals. 

• We also recommended that the EPA Administrator take steps to better 

ensure that EPA has the ability to develop transparent, credible IRIS 

assessments—an ability that relies in large part on EPA’s independence

in conducting these important assessments. 

Contrary to our recommendation, EPA has formalized a revised IRIS 

process that is selectively, rather than fully, transparent, limiting the 

credibility of the assessments. Specifically, while the draft process we 

reviewed provided that comments on IRIS assessments from OMB and 

other federal agencies would be part of the public record, under the 

recently implemented process, comments from federal agencies are 

expressly defined as “deliberative” and will not be included in the public 

record.8

 Given the importance and sensitivity of IRIS assessments, we 

believe it is critical that input from all parties, particularly agencies that 

may be affected by the outcome of IRIS assessments, be publicly available. 

However, under EPA’s new process, input from some IRIS assessment 

reviewers—representatives of federal agencies, including those facing 

potential regulatory liability, and private stakeholders associated with 

these agencies—will continue to receive less public scrutiny than 

comments from all others. 

In commenting on a draft of our March 2008 report, and in a recent 

congressional hearing, EPA’s Assistant Administrator, Office of Research 

and Development, stated that the IRIS process is transparent because all 

 7

The new IRIS assessment process refers to such chemicals as “mission critical.” The

process defines a mission-critical chemical as one that “is an integral component to the

successful and safe conduct of an agency’s mission in any or all phases of its operations.” 

According to the process, “impacts on the use of mission-critical chemicals include 

cessation or degradation of the conduct of the mission and/or unacceptable resource 

constraints.” 

8

Making these comments public would have been a change from the OMB/interagency 

review process that has been in place since 2004. 

Page 13 GAO-08-1168T 
final IRIS assessments must undergo public and external peer review. 

However, as we stated in our report, the presence of transparency at a 

later stage of IRIS assessment development does not explain or excuse its 

absence earlier. Under the new process, neither peer reviewers nor the 

public are privy to the changes EPA makes in response to the comments 

OMB and other federal agencies provide to EPA at several stages in the 

assessment process—changes to draft assessments or to the questions 

EPA poses to the peer review panels. Importantly, the first IRIS 

assessment draft that is released to peer reviewers and to the public 

includes the undisclosed input from federal agencies potentially subject to

regulation and therefore with an interest in minimizing the impacts of IRIS 

assessments on their budgets and operations. 

In addition, EPA’s revised process does not provide EPA with sufficient 

independence in developing IRIS assessments to ensure they are credible

and transparent. We made several recommendations aimed at restoring 

EPA’s independence. For example, we recommended that the EPA 

Administrator ensure that EPA has the ability to, among other things, 

define the appropriate role of external federal agencies in the IRIS 

assessment process and determine when interagency issues have been 

appropriately addressed. However, under the newly implemented IRIS 

assessment process, OMB continues to inform EPA when EPA has 

adequately addressed OMB’s and interagency comments. This 

determination must be made both before EPA can provide draft 

assessments to external peer reviewers and to the public and before EPA 

can finalize and post assessments on the IRIS database. While EPA 

officials state that ultimately IRIS assessments reflect EPA decisions, the 

new process does not support this assertion given the clearances EPA 

needs to receive from OMB to move forward at key stages. In fact, we 

believe the new IRIS assessment process may elevate the goal of reaching

interagency agreement above achieving IRIS program objectives. Further, 

as discussed above, because the negotiations over OMB/interagency

comments are not disclosed, whether EPA is entirely responsible for the 

content of information on IRIS is open to question. 

In our report, we also emphasized the importance of ensuring that IRIS 

assessments be based solely on science issues and not policy concerns. 

However, under the new IRIS assessment process, EPA has further 

introduced policy considerations into the IRIS assessment process. That 

is, the newly implemented IRIS assessment process broadens EPA’s 

characterization of IRIS assessments from “the agency’s scientific 

positions on human health effects that may result from exposure to 

environmental contaminants” to “the agency’s science and science policy 

Page 14 GAO-08-1168T 
positions” on such effects. EPA’s new, broader characterization of IRIS 

raises concerns about the agency’s stated intent to ensure that scientific 

assessments are appropriately based on the best available science and that

they are not inappropriately impacted by policy issues and considerations. 

For example, in discussing science and science policy at a recent Senate 

hearing, EPA’s Assistant Administrator of Research and Development 

described science policy considerations as including decisions about 

filling knowledge gaps (e.g., whether and to what extent to use default 

assumptions) and assessing weight-of-the-evidence approaches to make 

scientific inferences or assumptions. We believe that these are scientific 

decisions that should reflect the best judgment of EPA scientists who are 

evaluating the data, using the detailed risk assessment guidance the 

agency has developed for such purposes. We have concerns about the 

manner and extent to which other federal agencies, including those that 

may be affected by the outcome of assessments, are involved in these 

decisions as well as the lack of transparency of their input. As we 

highlighted earlier, under the National Academies’ risk assessment and 

risk management paradigm, policy considerations are relevant in the risk 

management phase—which occurs after the risk assessment phase that 

encompasses IRIS assessments. The National Academies recently 

addressed this issue as follows: “The committee believes that risk 

assessors and risk managers should talk with each other; that is, a 

‘conceptual distinction’ does not mean establishing a wall between risk 

assessors and risk managers. Indeed they should have constant 

interaction. However, the dialogue should not bias or otherwise color the 

risk assessment conducted, and the activities should remain distinct; that 

is, risk assessors should not be performing risk management activities.”9

EPA’s progress in completing assessments continues to be slow—only 

four final assessments have been completed in fiscal year 2008. Further, 

these assessments cover four related chemicals within a larger class of 

chemicals—polybrominated diphenyl ethers—that were processed and 

peer reviewed together in a single external peer review panel workshop, 

but finalized as four separate assessments. 

EPA’s Progress in 

Completing 

Assessments in Fiscal 

Year 2008 

 9

National Academies, Scientific Review of the Proposed Risk Assessment Bulletin from 

the Office of Management and Budget Committee to Review the OMB Risk Assessment 

Bulletin (2007). 

Page 15 GAO-08-1168T 
Moreover, little or no progress has been made on assessments of the key 

chemicals highlighted in our report—naphthalene, formaldehyde, Royal 

Demolition Explosive (RDX), trichloroethylene (TCE), tetrachloroethylene 

(perc), and 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). At the time of our 

March 2008 report, all of these assessments, with the exception of 

tetrachloroethylene, were in the draft development stage. As of September 

11, 2008, according to IRIS Track, none of these assessments had moved to

the next step—agency review. EPA’s current estimates for completing 

these assessments raise further concerns. For example, at the time of our 

report, EPA estimated that it would complete the naphthalene assessment 

in 2009, which would have reflected a total assessment time frame of 7 

years. However, since that time, EPA has updated its estimates in IRIS 

Track, which now indicate that naphthalene will not be completed until 

November 2011. In addition, EPA does not have any estimate of when it 

expects to complete three of the assessments—dioxin, RDX, and TCE. The 

estimated completion dates are listed as “to be determined” for these 

chemicals. This is particularly concerning for dioxin and TCE, which have 

already been in progress for over 17 years and over 10 years, respectively.

The new IRIS assessment process that EPA implemented in April 2008 will 

not allow the agency to routinely and timely complete credible 

assessments. In fact, it will exacerbate the problems we identified in our 

March 2008 report and sought to address with our recommendations—all 

of which were aimed at preserving the viability of this critical database, 

which is integral to EPA’s mission of protecting the public and the 

environment from exposure to toxic chemicals. Specifically, under the 

new process, assessment time frames will be significantly lengthened, and 

the lack of transparency will further limit the credibility of the 

assessments because input from OMB and other agencies at all stages of 

the IRIS assessment process is now expressly defined as deliberative and

therefore not subject to public disclosure. The position of the Assistant 

Administrator, Office of Research and Development, that the IRIS process 

is transparent because all final IRIS assessments must undergo public and 

external peer review is unconvincing. Transparency at a later stage of the 

IRIS assessment process—after OMB and other federal agencies have had 

multiple opportunities to influence the content of the assessment without 

any disclosure of their input—does not compensate for its absence earlier. 

We continue to believe that to effectively maintain IRIS EPA must 

streamline its lengthy assessment process and adopt transparency 

practices that provide assurance that IRIS assessments are appropriately

based on the best available science and that they are not inappropriately 

Concluding 

Observations 

Page 16 GAO-08-1168T 
biased by policy issues and considerations. As discussed in our April 29, 

2008, testimony before the Senate Environment and Public Works 

Committee and our May 21, 2008, testimony before the House 

Subcommittee on Investigations and Oversight, Committee on Science and

Technology, we believe that the Congress should consider requiring EPA 

to suspend implementation of its new IRIS assessment process and 

develop a streamlined process that is transparent and otherwise 

responsive to our recommendations aimed at improving the timeliness and 

credibility of IRIS assessments.10 For example, suspending assessments to 

obtain additional research is inefficient; alternatively, with longer-term 

planning, EPA could provide agencies and the public with more advance 

notice of assessments, enabling them to complete relevant research before 

IRIS assessments are started. 

In addition, as discussed in our testimonies, the Congress should consider 

requiring EPA to obtain and be responsive to input from the Congress and 

the public before finalizing a revised IRIS assessment process. We note 

that while EPA and OMB initially had planned for EPA to release a draft 

revised IRIS assessment process to the public, hold a public meeting to 

discuss EPA’s proposed changes, and seek and incorporate public input 

before finalizing the process, EPA released its new assessment process 

without obtaining public input and made it effective immediately. This was 

inconsistent with assertions made in OMB’s letter commenting on our 

draft report, which emphasized that EPA had not completed the 

development of the IRIS assessment process and stated: “Indeed, the 

process will not be complete until EPA circulates its draft to the public for

comments and then releases a final product that is responsive to those 

comments.”

Finally, if EPA is not able to take the steps we have recommended to 

effectively maintain this critical program, other approaches, including 

statutory requirements, may need to be explored. 

Mr. Chairman, this concludes my prepared statement. I would be happy to

respond to any questions that you or other Members of the Subcommittee 

may have at this time. 

 10GAO-08-743T and GAO-08-810T. 

Page 17 GAO-08-1168T 
For further information about this testimony, please contact John B. 

Stephenson on (202) 512-3841 or stephensonj@gao.gov. Contact points for 

our Congressional Relations and Public Affairs Offices may be found on 

the last page of this statement. Contributors to this testimony include 

Christine Fishkin (Assistant Director), Laura Gatz, Richard P. Johnson, 

and Nancy Crothers. 

Contacts and 

Acknowledgments 

Page 18 GAO-08-1168T 
Page 19 GAO-08-1168T 

Appendix I: Examples of Key IRIS 

Assessments That Have Been Delayed 

Some key IRIS assessments have been in progress for a number of years, 

in part because of delays stemming from one or more of the key factors we 

identified that have hindered EPA’s productivity.1

 Examples include the

following: 

Naphthalene. EPA started the IRIS assessment of cancer risks stemming 

from the inhalation of naphthalene in 2002. Naphthalene is used in jet fuel

and in the production of widely used commercial products such as moth 

balls, dyes, insecticides, and plasticizers. According to a presentation 

delivered at the 2007 annual meeting of the Society for Risk Analysis by an

Army Corps of Engineers toxicologist,

2

 “The changing naphthalene 

regulatory environment includes a draft EPA risk assessment that if/when 

finalized, will change naphthalene’s status from ‘possible’ to ‘likely’ human 

carcinogen.”3

 Thus, according to this presentation, one potential impact of 

this IRIS assessment on DOD is that DOD would need to provide many 

employees exposed to naphthalene with equipment measuring their 

exposure to the chemical. In addition, because many military bases are 

contaminated with naphthalene, a component of jet fuel (approximately 1 

percent to 3 percent) used by all DOD services, DOD could face extensive 

cleanup costs. By 2004, 2 years after starting the assessment, EPA had 

drafted a chemical assessment that had completed internal peer reviews 

and was about to be sent to an external peer review committee. Once it 

returned from external review, the next step, at that time, would have

been a formal review by EPA’s IRIS Agency Review Committee. If 

approved, the assessment would have been completed and released. 

 1

The factors we identified that have hindered EPA’s efforts to improve productivity are the

OMB/interagency review process managed by OMB, the growing complexity and scope of 

risk assessments, certain management decisions and issues regarding the IRIS program,

congressional action that has delayed some assessments with potentially significant 

economic effects, and the compounding effect of delays. 

2

Presentations at the Society for Risk Analysis meeting reflect the views of the authors and 

“do not necessarily reflect the views of any other organization or agency.”

3

Using its 1996 Proposed Guidelines for Carcinogen Risk Assessment, EPA concluded in

the 1998 IRIS assessment of naphthalene that its human carcinogenic potential could not

be determined at that time, but noted that there was suggestive evidence of potential 

human carcinogenicity. (EPA also noted that under its 1986 cancer guidelines, EPA 

classified naphthalene as a possible human carcinogen.) Subsequently, in 2002, the

International Agency for Research on Cancer (IARC), part of the World Health 

Organization, concluded that naphthalene is possibly carcinogenic to humans; in 2004, the 

Department of Health and Human Services’ National Toxicology Program concluded that 

naphthalene can reasonably be anticipated to be a human carcinogen. EPA’s current 

assessment will be subject to the agency’s 2005 cancer guidelines. 
However, in part because of concerns raised by DOD, OMB asked to 

review the assessment and conducted an interagency review of the draft. 

In their 2004 reviews of the draft IRIS assessment, both OMB and DOD 

raised a number of concerns about the assessment and suggested to EPA 

that it be suspended until additional research could be completed to 

address what they considered to be significant uncertainties associated 

with the assessment. Although all of the issues raised by OMB and DOD 

were not resolved, EPA continued with its assessment by submitting the 

draft for external peer review, which was completed in September 2004.4

However, according to EPA, OMB continued to object to the draft IRIS 

assessment and directed EPA to convene an additional expert review 

panel on genotoxicity to obtain recommendations about short-term tests 

that OMB thought could be done quickly.5

 According to EPA, this added 6 

months to the process, and the panel, which met in April 2005, concluded 

that the research that OMB was proposing could not be conducted in the 

short term. Nonetheless, EPA officials said that the second expert panel 

review did not eliminate OMB’s concerns regarding the assessment, which 

they described as reaching a stalemate. In September 2006, EPA decided, 

however, to proceed with developing the assessment. By this time, the 

naphthalene assessment had been in progress for over 4 years; EPA 

decided that the IRIS noncancer assessment, issued in 1998, was outdated 

and needed to be revisited. Thus, EPA expanded the IRIS naphthalene 

assessment to include both noncancer and cancer assessments. As a 

result, 6 years after the naphthalene assessment began, it is now back at 

the drafting stage. The assessment now will need to reflect relevant 

research completed since the draft underwent initial external peer review 

in 2004, and it will have to undergo all of the IRIS assessment steps again, 

including additional internal and external reviews that are now required. 

This series of delays has limited EPA’s ability to conduct its mission. For 

example, the Office of Air and Radiation has identified the naphthalene

assessment as one of its highest-priority needs for its air toxics program. 

In addition, the Office of Solid Waste and Emergency Response considers 

the naphthalene assessment a high priority for the Superfund program—

naphthalene has been found in at least 654 of Superfund’s current or 

former National Priorities List sites.6

 At the time of our March 2008 report, 

 4

According to DOD, EPA did not specifically ask the peer reviewers to address some of the

technical questions DOD had raised and wanted the peer review to address. 

5

Genotoxic substances are a type of carcinogen, specifically those capable of causing 

genetic mutation and of contributing to the development of tumors. This includes both 

certain chemical compounds and certain types of radiation. 

Page 20 GAO-08-1168T 
EPA estimated that it would complete the assessment in 2009. The agency

has since updated its estimate to reflect a later expected completion date,

November 30, 2011. 

Royal Demolition Explosive. This chemical, also called RDX or 

hexahydro-1,3,5-trinitrotriazine, is a highly powerful explosive used by the 

U.S. military in thousands of munitions. Currently classified by EPA as a 

possible human carcinogen, this chemical is known to leach from soil to 

groundwater. Royal Demolition Explosive can cause seizures in humans 

and animals when large amounts are inhaled or ingested, but the effects of

long-term, low-level exposure on the nervous system are unknown. As is 

the case with naphthalene, the IRIS assessment could potentially require 

DOD to undertake a number of actions, including steps to protect its 

employees from the effects of this chemical and to clean up many 

contaminated sites. Although EPA started an IRIS assessment of Royal 

Demolition Explosive in 2000, it has made minimal progress on the 

assessment because EPA agreed to a request by DOD to wait for the 

results of DOD-sponsored research on this chemical. In 2007, EPA began 

to actively work on this assessment, although some of the DOD-sponsored

research is still outstanding. 

Formaldehyde. EPA began an IRIS assessment of formaldehyde in 1997

because the existing assessment was determined to be outdated.7

Formaldehyde is a colorless, flammable, strong-smelling gas used to 

manufacture building materials, such as pressed wood products, and used 

in many household products, including paper, pharmaceuticals, and 

leather goods. While EPA currently classifies formaldehyde as a probable 

human carcinogen, the International Agency for Research on Cancer 

(IARC), part of the World Health Organization, classifies formaldehyde as 

a known human carcinogen. Since 1986, studies of industrial of workers 

have suggested that formaldehyde exposure is associated with 

nasopharyngeal cancer, and possibly with leukemia. For example, in 2003 

and 2004, the National Cancer Institute (NCI) and the National Institute of 

Occupational Safety and Health (NIOSH) released epidemiological studies

following up on earlier studies tracking about 26,000 and 11,000 industrial

workers, respectively, exposed to formaldehyde; the updates showed 

exposure to formaldehyde might also cause leukemia in humans, in 

addition to the cancer types previously identified. According to NCI 

 6

The National Priorities List is EPA’s list of seriously contaminated sites. 

7

The cancer portion of the formaldehyde assessment was originally issued in 1989 and 

updated in 1991; the noncancer assessment was added in 1990. 

Page 21 GAO-08-1168T 
officials, the key findings in their follow-up study were an increase in 

leukemia deaths and, more significantly, an exposure/response 

relationship between formaldehyde and leukemia—as exposure increased, 

the incidence of leukemia also rose. As with the earlier study, NCI found 

more cases of a rare form of cancer, nasopharyngeal cancer, than would 

usually be expected. The studies from NCI and NIOSH were published in

2003 and 2004,8

 around the time that EPA was still drafting its IRIS 

assessment. In November 2004, the Chairman of the Senate Environment 

and Public Works Committee requested that EPA delay completion of its

IRIS assessment until an update to the just-released NCI study could be

conducted, indicating that the effort would take, at most, 18 months. EPA 

agreed to wait—and almost 4 years later, the NCI update is not yet 

complete. NCI plans to release the results of its study in two 

publications—one focused on lymphatic and hematopoietic tumors and 

effects (including leukemia) and the other focused on other effects they 

observed (including other cancers). NCI estimates that the manuscript for 

the first stage may be published by early 2009. The second manuscript will 

likely not be published until late 2009. An NCI official said that the 

additional leukemia deaths identified in the update provide “greater 

power” to detect associations between exposure to formaldehyde and 

cancer. EPA’s inability to complete the IRIS assessment it started more 

than 10 years ago in a timely manner has had a significant impact on EPA’s 

air toxics program. Specifically, when EPA promulgated a national 

emissions standard for hazardous air pollutants covering facilities in the 

plywood and composite wood industries in 2004, EPA’s Office of Air and 

Radiation took the unusual step of not using the existing IRIS estimate but 

rather decided to use a cancer risk estimate developed by an industryfunded organization, the CIIT Centers for Health Research (formerly, the 

Chemical Industry Institute of Toxicology) that had been used by the 

Canadian health protection agency. The IRIS cancer risk factor had been 

 8

NCI published the results of its study in two publications. The first study, published in

November 2003, focused on the association between formaldehyde exposure and leukemia. 

M. Hauptmann, J. H. Lubin, P. A. Stewart, R. B. Hayes, A. Blair, “Mortality from 

Lymphohematopoietic Malignancies among Workers in Formaldehyde Industries,” Journal 

of the National Cancer Institute (2003). The second study, published in June 2004,

evaluated the association between formaldehyde exposure and other cancers—including 

nasopharyngeal cancer. M. Hauptmann, J. H. Lubin, P. A. Stewart, R. B. Hayes, A. Blair, 

“Mortality from Solid Cancers among Workers in Formaldehyde Industries,” American 

Journal of Epidemiology (2004). The results of the NIOSH study were described in one 

publication, dated March 2004, which assessed mortality from all causes and all cancers. L. 

E. Pinkerton, M. J. Hein, L. T. Stayner, “Mortality among a Cohort of Garment Workers 

Exposed to Formaldehyde: an Update,” Occupational and Environmental Medicine

(2004). 

Page 22 GAO-08-1168T 
subject to criticism because it was last revised in 1991 and was based on 

data from the 1980s. In its final rule, EPA stated that “the dose-response 

value in IRIS is based on a 1987 study, and no longer represents the best 

available science in the peer-reviewed literature.” The CIIT quantitative

cancer risk estimate that EPA used in its health risk assessment in the 

plywood and composite wood national emissions standard indicates a 

potency about 2,400 times lower than the estimate in IRIS that was being 

re-evaluated and that did not yet consider the 2003 and 2004 NCI and 

NIOSH epidemiological studies. According to an EPA official, an IRIS 

cancer risk factor based on the 2003 and 2004 NCI and NIOSH studies 

would likely be close to the current IRIS assessment, which EPA has been

attempting to update since 1997. The decision to use the CIIT assessment 

in the plywood national emissions standard was controversial, and 

officials in EPA’s National Center for Environmental Assessment said the 

center identified numerous problems with the CIIT estimate. Nonetheless, 

the Office of Air and Radiation used the CIIT value, and that decision was 

a factor in EPA exempting certain facilities with formaldehyde emissions 

from the national emissions standard. In June 2007, a federal appellate

court struck down the rule, holding that EPA’s decision to exempt certain 

facilities that EPA asserted presented a low health risk exceeded the 

agency’s authority under the Clean Air Act.9

 Further, the continued delays 

of the IRIS assessment of formaldehyde—currently estimated to be 

completed at the end of 200910 but after almost 11 years still in the draft 

development stage—will impact the quality of other EPA regulatory 

actions, including other air toxics rules and requirements. 

Trichloroethylene. Also known as TCE, this chemical is a solvent widely

used as a degreasing agent in industrial and manufacturing settings; it is a 

common environmental contaminant in air, soil, surface water, and 

groundwater. TCE has been linked to cancer, including childhood cancer, 

and other significant health hazards, such as birth defects. TCE is the most 

frequently reported organic contaminant in groundwater, and 

contaminated drinking water has been found at Camp Lejeune, a large 

Marine Corps base in North Carolina. TCE has also been found at 

 9

Natural Resources Defense Council v. E.P.A., 489 F.3d 1364, 1372-73 (D.C. Cir, 2007). The

court did not specifically address EPA’s reliance on the CIIT study, holding instead that the

Clean Air Act prohibited establishment of the exemptions at issue. 

10At the time of our March 2008 report, EPA estimated that the assessment would not be

complete until 2010. The current estimate of 2009 appears optimistic in light of continued 

delays in the NCI study updates. 

Page 23 GAO-08-1168T 
Superfund sites and at many industrial and government facilities, including 

aircraft and spacecraft manufacturing operations. In 1995, the 

International Agency for Research on Cancer classified TCE as a probable

human carcinogen, and in 2000, the Department of Health and Human 

Services’ National Toxicology Program concluded that it is reasonably 

anticipated to be a human carcinogen. Because of questions raised by peer

reviewers about the IRIS cancer assessment for TCE, EPA withdrew it 

from IRIS in 1989 but did not initiate a new TCE cancer assessment until 

1998. In 2001, EPA issued a draft IRIS assessment for TCE that proposed a 

range of toxicity values indicating a higher potency than in the prior IRIS 

values and characterizing TCE as “highly likely to produce cancer in 

humans.” The draft assessment, which became controversial, was peer 

reviewed by EPA’s Scientific Advisory Board and released for public 

comment. A number of scientific issues were raised during the course of 

these reviews, including how EPA had applied emerging risk assessment 

methods—such as assessing cumulative effects (of TCE and its 

metabolites) and using a physiologically based pharmacokinetic model—

and the uncertainty associated with the new methods themselves.11 To 

help address these issues, EPA, DOD, DOE, and NASA sponsored a 

National Academies review to provide guidance. The National Academies 

report, which was issued in 2006, concluded that the weight of evidence of 

cancer and other health risks from TCE exposure had strengthened since 

2001 and recommended that the risk assessment be finalized with 

currently available data so that risk management decisions could be made

expeditiously. The report specifically noted that while some additional 

information would allow for more precise estimates of risk, this 

information was not necessary for developing a credible risk assessment. 

Nonetheless, 10 years after EPA started its IRIS assessment, the TCE 

assessment is back at the draft development stage. At the time of our 

March 2008 report, EPA estimated that this assessment would be finalized

in 2010. Since that time, EPA has modified the expected completion date

to “to be determined.” More in line with the National Academies’ 

recommendation to act expeditiously, five senators introduced a bill in

August 2007 that, among other things, would require EPA to both establish 

IRIS values for TCE and issue final drinking water standards for this 

contaminant within 18 months. 

 11Physiologically based pharmacokinetic models are a class of dosimetry models that are

useful for predicting internal doses to target organs. With the appropriate data, these 

models can be used to extrapolate across species and exposure scenarios and address 

various sources of uncertainty in risk assessments. 

Page 24 GAO-08-1168T 
Tetrachloroethylene. EPA started an IRIS assessment of 

tetrachloroethylene—also called perchloroethylene or “perc”—in 1998.

Tetrachloroethylene is a manufactured chemical widely used for dry 

cleaning of fabrics, metal degreasing, and making some consumer 

products and other chemicals. Tetrachloroethylene is a widespread 

groundwater contaminant, and the Department of Health and Human 

Services’ National Toxicology Program has determined that it is 

reasonably anticipated to be a carcinogen. The IRIS database currently 

contains a 1988 noncancer assessment based on oral exposure that will be

updated in the ongoing assessment. Importantly, the ongoing assessment 

will also provide a noncancer inhalation risk and a cancer assessment. The 

IRIS agency review of the draft assessment was completed in February 

2005, the draft assessment was sent to OMB for OMB/interagency review 

in September 2005, and the OMB/interagency review was completed in 

March 2006. EPA had determined to have the next step, external peer 

review, conducted by the National Academies—the peer review choice 

reserved for chemical assessments that are particularly significant or 

controversial. EPA contracted with the National Academies for a review 

by an expert panel, and the review was scheduled to start in June 2006 and 

be completed in 15 months. However, as of December 2007, the draft 

assessment had not yet been provided to the National Academies. After 

verbally agreeing with both the noncancer and cancer assessments 

following briefings on the assessments, the Assistant Administrator, Office 

of Research and Development, subsequently requested that additional 

uncertainty analyses—including some quantitative analyses—be 

conducted and included in the assessment before the draft was released to

the National Academies for peer review. As discussed in our March 2008 

report on IRIS (GAO-08-440), quantitative uncertainty analysis is a risk 

assessment tool that is currently being developed, and although the agency 

is working on developing policies and procedures for uncertainty analysis, 

such guidance currently does not exist. At the time of our March 2008 

report, we indicated that the draft tetrachloroethylene assessment had 

been delayed since early 2006 as EPA staff went back and forth with the 

Assistant Administrator trying to reach agreement on key issues such as 

whether a linear or nonlinear model was most appropriate for the cancer 

assessment and how uncertainty should be qualitatively and quantitatively 

characterized. EPA officials and staff noted that some of the most 

experienced staff were being used for these efforts, limiting their ability to

work on other IRIS assessments. In addition, we noted that the significant 

delay had impacted the planned National Academies peer review because

the current contract, which has already been extended once, cannot be 

extended beyond December 2008. The peer review was initially estimated 

to take 15 months. Since the time of our March 2008 report, EPA released 

Page 25 GAO-08-1168T 
the draft assessment for public comment and held a “listening session”12 to 

receive comments. However, the agency has not yet announced a date or a 

location for the external peer review in the Federal Register. 

Dioxin. The dioxin assessment is an example of an IRIS assessment that 

has been, and will likely continue to be, a political as well as a scientific 

issue. Often the byproducts of combustion and other industrial processes, 

complex mixtures of dioxins enter the food chain and human diet through

emissions into the air that settle on soil, plants, and water. EPA’s initial 

dioxin assessment, published in 1985, focused on the dioxin TCDD 

(2,3,7,8-tetrachlorodibenzo-p-dioxin) because animal studies in the 1970s 

showed it to be the most potent cancer-causing chemical studied to date.

Several years later, EPA decided to conduct a reassessment of dioxin 

because of major advances that had occurred in the scientific

understanding of dioxin toxicity and significant new studies on dioxins’ 

potential adverse health effects. Initially started in 1991, this assessment 

has involved repeated literature searches and peer reviews. For example, a 

draft of the updated assessment was reviewed by a scientific peer review 

panel in 1995, and three panels reviewed key segments of later versions of 

the draft in 1997 and 2000. In 2002, EPA officials said that the assessment 

would conclude that dioxin may adversely affect human health at lower 

exposure levels than had previously been thought and that most exposure 

to dioxins occurs from eating such American dietary staples as meats, fish, 

and dairy products, which contain minute traces of dioxins. These foods 

contain dioxins because animals eat plants and commercial feed and drink 

water contaminated with dioxins, which then accumulate in animals’ fatty 

tissue. It is clear that EPA’s dioxin risk assessment could have a 

potentially significant impact on consumers and on the food and 

agriculture industries. As EPA moved closer to finalizing the assessment, 

in 2003 the agency was directed in a congressional appropriations 

conference committee report to not issue the assessment until it had been

reviewed by the National Academies. The National Academies provided 

EPA with a report in July 2006. In developing a response to the report, 

which the agency is currently doing, EPA must include new studies and 

risk assessment approaches that did not exist when the assessment was 

drafted. EPA officials said the assessment will be subject to the IRIS 

review process once its response to the National Academies’ report is 

 12EPA’s new assessment process includes a “listening session” open to interested parties

that provides interested parties with an opportunity to present scientific and technical 

comments on draft IRIS health assessments to EPA and other interested parties during a

public comment period and prior to the external peer review meeting. 

Page 26 GAO-08-1168T 
drafted. As of 2008, EPA has been developing the dioxin assessment, 

which has potentially significant health implications for all Americans, for 

17 years. 

Page 27 GAO-08-1168T 
Page 28 GAO-08-1168T 

Appendix II: EPA’s IRIS Assessment Process 

Being Implemented at the Time of Our Review 

(Includes OMB Requirements as of 2005) 

Annual request for 

nomination of IRIS 

chemicals for assessment 

Scientific literature search 

Determine the annual 

agenda and publish it in 

the Federal Register,

along with a call for 

scientific information from 

the public on select 

chemicals 

Development of a complete draft 

IRIS assessment (qualitative and 

quantitative), including internal 

peer consultation

Internal agency review by the 

18-member IRIS Agency Review 

Committee 

Revised draft IRIS assessment 

OMB/interagency review 

coordinated by OMB

Revised draft IRIS assessment 

Independent external peer 

review and public comment 

Revised draft IRIS 

assessment

Second internal agency 

review by the 18-member 

IRIS Agency Review 

Committee

Second OMB/interagency 

review coordinated by 

OMB

Completion of IRIS assessment, 

EPA management review and 

approval, and posting on IRIS 

Source: GAO analysis of EPA information.
Page 29 GAO-08-1168T 

Appendix III: EPA’s Draft Proposed IRIS 

Assessment Process Being Considered at the 

Time of Our Review (Dated March 2007) 

Annual request for 

nomination of IRIS chemicals 

for assessment

Determine the annual 

agenda and publish it in the 

Federal Register

Scientific literature search

Federal Register 

notice/data call-in

Development of a draft 

qualitative assessment

Public review of draft 

qualitative assessment

Review of public comments

Interagency evaluation to 

close data gaps

Federal agency development of new studies

Is the

chemical mission

critical?

Is there

interest in

conducting research

to close data

gaps?

Yes, it is mission critical. 

No, it is not mission critical. 

No, there is no 

interest in conducting 

new research to 

close data gaps. 

Yes, there is interest in conducting 

research to close data gaps. 
Development of a complete 

draft IRIS assessment 

(qualitative and quantitative), 

including internal peer 

consultation

Internal agency review by 

the 18-member IRIS Agency 

Review Committee

Revised draft IRIS 

assessment

OMB/interagency review 

coordinated by OMB

Revised draft IRIS 

assessment

Independent external peer 

review and public comment

Revised draft IRIS 

assessment

Second internal agency 

review by the 18-member 

IRIS Agency Review 

Committee

Second 

OMB/interagency 

review coordinated by 

OMB

Completion of IRIS 

assessment, EPA 

management review 

and approval, and 

posting on IRIS

Darker shaded boxes are additional steps, under EPA’s planned changes, to its

assessment process and indicate steps where EPA has provided additional opportunity for input

from potentially affected federal agencies for mission-critical chemicals.

Lighter shaded boxes with dotted lines indicate steps where EPA has provided additional

opportunity for input from potentially affected federal agencies for all chemicals.

White boxes with heavy lines indicate steps where potentially affected federal agencies already

had an opportunity for input.

Is the chemical 

mission critical? 

EPA consults 

with federal 

agencies to 

determine level 

and scope of 

peer review 

EPA determines 

the level and 

scope of the 

peer review 

Yes No 

Source: GAO analysis of EPA information.

Page 30 GAO-08-1168T 
Page 31 GAO-08-1168T 

Appendix IV: EPA’s IRIS Assessment Process 

as of April 10, 2008 

Annual request for 

nomination of IRIS chemicals 

for assessment

Determine the annual 

agenda and publish it in the 

Federal Register

Scientific literature search

Federal Register 

notice/data call-in

Development of a draft 

qualitative assessment

Federal agency and public 

review of draft qualitative 

assessment

EPA and federal agency

review of comments

Interagency evaluation to 

close data gaps

Federal agency 

development of new studies

Is the

chemical mission

critical?

Is there

interest in

conducting research

to close data

gaps?

Yes, it is mission critical.

No, it is not mission critical.

No, there is no

interest in conducting

new research to

close data gaps.

Yes, there is interest in conducting

research to close data gaps.
Development of a complete 

draft IRIS assessment 

(qualitative and quantitative), 

including internal peer 

consultation

Internal agency review by 

the 18-member IRIS Agency 

Review Committee

Revised draft IRIS 

assessment

OMB/interagency review 

coordinated by OMB

Revised draft IRIS 

assessment

Independent external peer 

review and public comment

Revised draft IRIS 

assessment

Second internal agency 

review by the 18-member 

IRIS Agency Review 

Committee

Second 

OMB/interagency 

review coordinated by 

OMB

Completion of IRIS 

assessment, EPA 

management review 

and approval, and 

posting on IRIS

Darker shaded boxes are additional steps under EPA’s changes to its assessment 

process and indicate where EPA has provided additional opportunity for input

from potentially affected federal agencies for mission-critical chemicals.

Lighter shaded boxes with dotted lines indicate steps where EPA has provided additional

opportunity for input from potentially affected federal agencies for all chemicals.

White boxes with heavy lines indicate steps where potentially affected federal agencies already

had an opportunity for input.

Is the chemical

mission critical?

EPA consults

with federal

agencies to

determine level

and scope of

peer review

EPA determines

the level and

scope of the

peer review

Yes No

Source: GAO analysis of EPA information.

Page 32 GAO-08-1168T (361010) 
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