APPENDIX N 

Integrated Risk Information System 

Background Paper 

WATER QUALITY STANDARDS HANDBOOK 

SECOND EDITION 
IRIS 

BACKGROUND 

PAPER 

Integrated Risk Information System 

Office of Health and Environmental Environmental Assessment Assessment 

Office of Research and Development 

FEBRUARY, 1993 VERSION 1.0 
IRIS Background Paper 

On February 25, 1993, a FEDERAL REGISTER notice (58 FR 11490) was 

published on the Integrated Risk Information System (IRIS). This background paper is 

a companion piece to that notice. 

Table of Contents 

lntroduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

General Background . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 

Data Base Contents ................................. 3 

Noncancer Health Effects Information ............... 3 

Cancer Effects Health Information .................. 4 

Scientific Contacts ............................. 4 

Bibliographies ................................ 5 

Supplementary Information ....................... 5 

Use and Development of Health Hazard Information . . . . . . . . . . 5 

Management . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Oversight . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6 

Information Development Process ....................... 6 

CRAVE ..................................... 6 

RfD/RfC .................................... 8 

Methods and Guidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 

Public Involvement . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11 

For further information on IRIS, please contact: 

IRIS User Support 

(Operated by Computer Sciences Corporation) 

26 W. Martin Luther King Drive (MS-190) 

Cincinnati, OH 45268 

Telephone (513) 569-7254 Facsimile (513) 569-7916 
Introduction 

This background paper provides the history, purposes, and goals of the 

Integrated Risk Information System (IRIS) and a detailed description of the current 

processes used by the two Agency scientific work groups responsible for developing 

the health hazard information in IRIS. This background will help interested persons to 

better understand the focus and contents of the companion FEDERAL REGISTER 

notice. 

The February 25, 1993 FEDERAL REGISTER notice (58 FR 11490): (1) 

announces the availability of this paper that describes IRIS, its contents, and the 

current processes used by the two Agency work groups responsible for developing 

IRIS information; (2) discusses an Agency activity to review IRIS processes and solicits 

comments on this review; (3) highlights points in the current process where public 

input, including information submissions, is encouraged; (4) describes how to access 

IRIS; and (5) announces a new process to publish regularly a list of the substances 

scheduled for IRIS work group review and to solicit pertinent data, studies, and 

comments on these substances. 

General Background 

IRIS is an EPA data base, updated monthly, containing Agency consensus 

positions on the potential adverse human health effects of approximately 500 specific 

substances. It contains summaries of EPA qualitative and quantitative human health 

information that support two of the four major steps of the risk assessment process 

outlined in the National Research Council’s (NRC) 1983 publication, “Risk Assessment 

in the Federal Government: Managing the Process.” 

The risk assessment process described in the 1983 NRC publication consists of 

four major steps: hazard identification, dose-response evaluation, exposure 

assessment, and risk characterization. IRIS includes information in support of the first 

two of those steps, hazard identification and dose-response evaluation. Hazard 

identification is the qualitative determination of how likely it is that a substance will 

increase the incidence and/or severity of an adverse health effect. Dose-response 

evaluation is the quantitative relationship between the magnitude of the effect and the 

dose inducing such an effect. IRIS information supporting risk characterization 

consists of brief statements on the quality of data and very general statements on 

confidence in the dose-response evaluation. IRIS consensus information does not 

include exposure assessment information. Combined with specific situational 

exposure assessment information, the summary health hazard information in IRIS may 

be used as one source in evaluating potential public health risks of or from 

environmental contaminants. 
Many EPA program offices and program support offices, including the Office 

of Research and Development, both at Headquarters and in EPA’s ten Regional 

offices, are involved in assessment activities in support of various legislative mandates. 

In the 1980s as health risk assessment became a more widespread practice across 

Agency programs, the need became clear for greater consensus and consistency in 

the areas of hazard identification and dose-response assessment. It was determined 

that an internal process should be established for reaching an Agency-wide judgment 

on the potential health effects of substances of common interest to these offices, and 

a system developed for communicating that Agency judgment to EPA risk assessors 

and risk managers. These would provide the needed consistency and coordination. 

In 1986, two EPA work groups with representation from program offices involved in 

risk assessment were convened to carry out such an internal process to reach 

consensus Agency positions on a chemical-by-chemical basis. In 19*6, the IRIS data 

base was created for EPA staff as the official repository of that consensus information. 

On June 2, 1988, a FEDERAL REGISTER notice (53 FR 20162-20164) of public 

availability of IRIS was published. That notice described IRIS, the types of risk 

information it contains, and how to get access to the system. It informed the public 

about the establishment of the IRIS Information Submission Desk. The submission 

desk was intended to provide opportunity for public input. The notice explained the 

procedures for submission of data or comments by interested parties on substances 

either on IRIS or scheduled for review by the work groups. As stated in the June 1988 

notice, a list of the substances scheduled for work group review has been a separate 

file on IRIS since it became publicly available. It was hoped that users would submit 

pertinent information to the IRIS Information Submission Desk. In fact, few users have 

taken advantage of the opportunity to submit data and comments. 

Therefore, data submission procedures are reiterated in the FEDERAL 

REGISTER notice (56 FR 11490) related to this paper and a list of the substances 

scheduled for review by specific work groups is included. The data submission 

procedures will be reprinted in the FEDERAL REGISTER every 6 months with a new or 

revised list of substances scheduled for work group review. For the latest status of 

the substances scheduled for review, interested persons should first check the IRIS 

data base itself or contact: 

IRIS User Support (Operated by Computer Sciences Corporation) 

U.S. EPA 

26 W. Martin Luther King Drive (MS-190) 

Cincinnati, OH 45266 

Telephone: (513) 569-7254 Facsimile: (513) 569-7916 
Data Base Contents 

The core of IRIS is the three consensus health hazard information summary 

sections: the reference dose for noncancer health effects resulting from oral 

exposure, the reference concentration for noncancer health effects resulting from 

inhalation exposure, and the carcinogen assessment for both oral and inhalation 

exposure. All of these terms are commonly used for judging the effects of lifetime 

exposure to a given substance or mixture. Citations for the scientific methodologies 

that are the basis for the consensus health hazard sections on IRIS are included on 

page 10 of this paper. 

In addition, an IRIS substance file may include supplemental information such 

as summaries of health advisories, regulatory actions, and physical/chemical 

properties. 

Noncancer Health Effects Information 

An oral reference dose (RfD) is an estimate (with uncertainty spanning perhaps 

an order of magnitude) of a daily oral exposure to the human population (including 

sensitive subgroups) that is believed likely to be without an appreciable risk of certain 

deleterious effects during a lifetime (“Reference Dose [RfD]; Description and Use in 

Health Risk Assessment” Regulatory Toxicology and Pharmacology 8:471-486, 1988). 

RfDs are developed by an assessment method that assumes that there is a dose 

threshold below which adverse effects will not occur. An RfD, which is expressed in 

milligrams per kilogram per day (mg/kg-day), is based on the determination of a 

critical effect from a review of all toxicity data and a judgment of the necessary 

uncertainty and modifying factors based on a review of available data. IRIS substance 

files contain the following information pertaining to the oral RfD: reference dose 

summary tables, principal and supporting studies, uncertainty and modifying factors 

used in calculating the RfD, a statement of confidence in the RfD, EPA documentation 

and review, EPA scientific contacts, and complete bibliographies for references cited. 

The inhalation reference concentration (RfC) is analogous to the oral RfD 

(Interim Methods for Development of Inhalation Concentrations, EPA/600/8-90/066A). 

It is also based on the assumption that thresholds exist for noncancer toxic effects. 

The RfC considers toxic effects for both the respiratory system (portal-of-entry) and for 

effects peripheral to the respiratory system (extra-respiratory). The inhalation RfC is 

expressed in milligrams per cubic meter (mg/cu.m). The RfC method departs from 

that used to determine the oral RfD primarily by the integration of the anatomical and 

physiological dynamics of the respiratory system (i.e., portal-of-entry) with the 

physicochemical properties of the substance or substances entering the system. 

Different dosimetric adjustments are made according to whether the substance is a 

particle or gas and whether the observed toxicity is respiratory or extra-respiratory. 

These adjustments scale the concentration of the substance that causes an observed 

effect in laboratory animals (or in humans, when available from occupational 

epidemiology studies) to a human equivalent concentration for ambient exposures. 

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IRIS substance files contain the following inhalation RfC information: reference 

concentration summary tables, description of dosimetric adjustment, principal and 

supporting studies, uncertainty and modifying factors used to calculate the RfC, a 

statement of confidence in the RfC, EPA documentation and review, EPA scientific 

contacts, and complete bibliographies for references cited. 

Cancer Health Effects Information 

The carcinogen assessment of an IRIS substance file contains health hazard 

identification and dose-response assessments developed from procedures outlined in 

the EPA Guidelines for Carcinogen Risk Assessment (51 FR 33992-43003, September 

24, 1986). Each cancer assessment, as a rule, is based on an Agency document that 

has received external peer review. The hazard identification involves a judgment in the 

form of a weight-of-evidence classification of the likelihood that the substance is a 

human carcinogen. It includes the type of data used as the basis of the classification. 

This judgment is made independently of considerations of the strength of the possible 

response. The dose-response assessment is a quantitative estimate of the potential 

activity or magnitude of a substance’s carcinogenic effect, usually expressed as a 

cancer unit risk. A cancer unit risk is an upper-bound estimate on the increased 

likelihood that an individual will develop cancer when exposed to a substance over a 

lifetime at a concentration of either 1 microgram per liter (1 μg/L) in drinking water for 

oral exposure or 1 microgram per cubic meter (1 μg/cu.m) in air for continuous 

inhalation exposure. Generally, a slope factor for dietary use is also given. It is an 

upper-bound estimate of cancer risk for humans per milligram of agent per kilogram of 

body weight per day. 

IRIS contains the following information in the cancer assessment section: EPA 

weight-of-evidence classification and its basis, a summary of human carcinogenicity 

studies when available, a summary of animal carcinogenicity studies, a summary of 

other data supporting the classification, oral and/or inhalation quantitative estimates, 

dose-response data used to derive these estimates and the method of calculation, 

statements of confidence in magnitude of unit risk, documentation and review, EPA 

scientific contacts, and complete bibliographies for references cited. 

Scientific Contacts 

It is important to note that in each of the three sections described above, EPA 

staff names and telephone numbers are included as scientific contacts for further 

information. The Agency believes that the inclusion of Agency scientific contacts able 

to discuss the basis for the Agency’s position, has been very valuable. These 

individuals play a major role in providing public access to IRIS and a conduit for 

valued public comment. 

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Bibliographies 

IRIS contains full bibliographic citations for each substance file, directing the 

user to the primary cited studies and pertinent scientific literature. One of the major 

intents of IRIS was to encourage users to evaluate the primary literature used to 

develop the IRIS information in light of the assumptions and uncertainties underlying 

the risk assessment process. 

Supplementary Information 

In addition to the RfD, RfC, and carcinogenicity sections, IRIS substance files 

may contain one or more of three supplementary information sections: a summary of 

an Office of Water’s Drinking Water Health Advisory, a summary of EPA regulatory 

actions, and a summary of physical/chemical properties. The only purpose of these 

supplemental sections is to serve as accessory information to the consensus health 

hazard information. Since the primary intent of the IRIS data base is to communicate 

EPA consensus health hazard information, these other sections are only included as 

auxiliary material to provide a broader profile of a substance and are never added until 

at least one of the consensus health hazard sections described above (namely, the 

RfD section, RfC section, or carcinogenicity section) is prepared and approved for final 

inclusion on the data base. These supplemental sections should not be used as the 

sole or primary source of information on the current status of EPA substance-specific 

regulations. 

Use and Development of Health Hazard Information 

The type of substance-specific consensus health hazard information on IRIS 

may become part of the supporting materials used to develop site-specific EPA health 

hazard assessments. These assessments may in turn lead to EPA risk management 

decisions, generally resulting in the formal Agency rulemaking process. This 

rulemaking process often includes FEDERAL REGISTER publication of a proposed rule 

where the public is encouraged to comment. These comments may be directed at 

both the proposed rule and the scientific basis of the decision, including information 

obtained from IRIS and thus offer a further opportunity for comment on the risk 

information in the context of its use. 

The area of human health risk assessment has evolved over the past several 

years. As the risk assessment community has grown and the field itself has matured, 

new approaches to the assessment and use of human health risk information have 

been developed. The evolving nature of risk assessment has also resulted in changes 

to IRIS. The development of methodologies such as those for the inhalation RfC 

determination illustrates the ability of the IRIS information development process to 

grow with the changing science. Areas of future growth may include less-than-lifetime 

risk information and developmental toxicity risk information and other endpoint-specific 

health hazard information. Also, on several occasions, the information in IRIS has 

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been reevaluated and modified to reflect new information and approaches. New 

studies on individual substances are continually being conducted by Federal, private, 

and academic institutions and may have significant impact on IRIS information. In 

those cases, the IRIS substance information is reevaluated in light of the new data; 

any changes resulting from that reevaluation are included on the system. 

Management of the Data Base 

The IRIS data base is managed and maintained by the Office of Health and 

Environmental Assessment (OHEA), Office of Research and Development (ORD). IRIS 

is an Agency system primarily funded by OHEA with additional significant support from 

EPA program offices. 

Oversight 

Oversight activities for IRIS are conducted by the IRIS Oversight Committee, a 

subgroup of the Agency’s Risk Assessment Council. Committee membership consists 

of senior Agency risk assessors. The main purpose of the IRIS Oversight Committee 

is to serve as a forum for discussion and advice on significant scientific or science 

policy issues involving IRIS. The Council, which is chaired by EPA’s Deputy 

Administrator, receives periodic status reports on IRIS and related work group 

activities. 

Information Development Process 

There are two EPA work groups, the Carcinogen Risk Assessment Verification 

Endeavor (CRAVE) and the Oral Reference Dose/Inhalation Reference Concentration 

(RfD/RfC) Work Group, that develop consensus health hazard information for IRIS. 

Each group consists of EPA scientists from a mix of pertinent disciplines and 

represents intra-Agency membership. The work groups serve as the Agency’s final 

review for EPA risk assessment information. When the work groups reach consensus 

on the health effects information and the dose-response assessment for a particular 

substance, the descriptive summary is added to IRIS. 

CRAVE: Information Development Procedures 

The goals of the CRAVE are to reach Agency consensus on Agency carcinogen 

risk assessments; to arrive at a unified view on potential cancer risk from exposure to 

specific substances across Agency programs; and to identify, discuss, and resolve 

general issues associated with methods used to estimate carcinogenic risks for 

specific agents. The major outputs of the work group are summaries of risk 

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information that have been previously developed and documented by scientific experts 

in Agency program and program support offices, and results of discussions of general 

issues in carcinogen risk assessment. 

Scientists are selected by executive appointment from respective member 

offices. Membership is open to all major Agency program and regional offices, ORD, 

and the Office of Policy, Planning, and Evaluation (OPPE). Substances are discussed 

at the request of Agency offices or regions according to an established timetable. The 

CRAVE priorities are determined by the member offices. The office requesting review 

prepares a summary describing both a judgment on the weight-of-evidence for 

potential health hazard effects and any dose-response information for the substances 

according to an established format. Literature files on the substances including critical 

studies, pertinent EPA documents, and other relevant supporting documentation are 

made available to work group members in advance of the meeting. Generally, the 

judgment and the dose-response assessment are expected to have appeared in a 

publicly available document of some sort. 

The CRAVE usually meets bimonthly for two days. Work group members 

normally receive draft summaries for pre-meeting review at least one week prior to the 

scheduled meeting. At the meeting, data and documentation are examined, and there 

is discussion of the basis for the risk information and the methods by which it was 

derived. In addition, the nature and extent of previous internal and external peer 

review, including the comments received, are reviewed by the work group. The 

summary is revised by the office originating the review to reflect the meeting 

discussion and accurately express the consensus view of the work group. After the 

process of revision is completed, the summary is circulated again to the work group 

for final approval prior to its inclusion on IRIS. 

Consensus means that no member office is aware either of information that 

would conflict with the final carcinogenicity summary, or of analyses that would 

suggest that a different view is more credible. Such assurance rests on the 

capabilities of the individuals who represent their offices; thus, every effort is made to 

seek scientists who are both expert in the area of human health assessment and who 

can represent their office. 

Peer review has generally been part of the IRIS information development 

processes from the beginning of the system. In the preparation of summaries, 

emphasis has been placed on the use of peer-reviewed EPA assessments. These 

have included Office of Pesticide Programs assessments that have received both 

program office peer review and Science Advisory Panel review. Other EPA 

documentation includes assessments prepared by OHEA such as Health Assessment 

Documents, Health and Environmental Effects Documents, and Health Effects 

Assessments. These documents receive OHEA review and program office review and 

some receive Science Advisory Board (SAB) or other external review. Assessments 

developed by or for the Office of Ground Water and Drinking Water and incorporated 

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in either Drinking Water or Ambient Water Criteria Documents, or in Drinking Water 

Health Advisories generally receive extensive Agency review and SAB review prior to 

discussion by CRAVE. 

On occasion, risk assessments that were contained in draft documents have 

been discussed by CRAVE. In these instances, results of the work group 

deliberations have been incorporated into the document development process at the 

program office or program support office level. Loading of the information on IRIS is 

delayed pending completion of the document. 

If consensus is not reached at the meeting it is generally because an issue is 

raised that requires resolution. Work group deliberations continue until consensus is 

achieved. In the case of substance-specific issues, the substance is referred back to 

the member office that initiated the review for more information and clarification. In 

some instances, it has been necessary for more than one program office to engage in 

a dialogue to resolve the issue. 

For general issues, CRAVE practice has been to form a subcommittee to 

prepare an issue paper that is subsequently discussed at a special meeting. As 

examples of this process, issue papers have been developed for (1) issues relating to 

accuracy and precision of quantitative dose-response information, (2) factors involving 

confidence in quantitative estimates, and (3) use of split classifications and combining 

estimates. 

When consensus is not achieved on a particular substance at a meeting of the 

CRAVE, it is considered to have “under review” status. If after three months, there is 

no further activity to bring the substance back to the work group for additional review, 

the substance loses its “under review” status. The substance is then dropped from 

the work group review list after notifying the responsible office. Any office may 

resubmit the substance for further discussion at any time. 

Reference Dose (RfD)/Reference Concentration (RfC): Information Development 

Procedures 

The purpose of the RfD/RfC Work Group is to reach consensus on oral RfDs and 

inhalation RfCs for noncancer chronic human health effects developed by or in support 

of program offices and the regions. The work group also works to resolve inconsistent 

RfDs or RfCs among program offices and to identify, discuss, and resolve generic issues 

associated with methods used to estimate RfDs and RfCs. 

Scientists are selected by executive appointment from respective member offices. 

Membership is open to all major Agency program and regional offices. There are two 

work group co-chairs. In addition, scientists from the Agency for Toxic Substances and 

Disease Registry and the Food and Drug Administration are invited to work group 

meetings as observers to assist the Agency in the information gathering process. Their 

8 
involvement fosters better communication and coordination among federal agencies 

regarding assessment approaches and data evaluation. Members reflect a variety of 

pertinent scientific disciplines including expertise in the fields of general and inhalation 

human toxicology. 

Member offices schedule substances for discussion through the work group cochairs for specific meetings, usually one or two months in advance. Regional requests 

for specific substance discussions are routed through the co-chairs, who then either 

schedule these substances in the usual manner or, if the region has not prepared a file, 

requests an appropriate office to undertake that task. 

The RfD/RfC Work Group usually meets once a month for two days. Substances 

are discussed at the request of any Agency office or region. The requesting office 

generally prepares a file that consists of a summary sheet, a copy of the critical study and 

supporting documentation, and distributes these to work group members prior to the 

meeting. 

Consensus generally means that no member office is aware either of information 

that would conflict with the RfD or RfC, or of analyses that would suggest a different value 

that is more credible. Such assurance rests on the capabilities of the individuals who 

represent their offices; thus, a large effort is conducted biannually to seek scientists who 

are both expert in this area of assessment and can represent their offices. 

RfD or RfC summaries are not always based on existing EPA assessment 

documents but may be based on assessments prepared specifically for the work group. 

This is a fundamental difference between the usual processes of the RfD/RfC Work Group 

and those of CRAVE. As stated previously, the general rule has been that for a 

substance to be brought to the CRAVE Work Group for review there should be an 

existing peer-reviewed Agency health effects document. However, for RfDs there may or 

may not be an existing EPA document on which to base work group deliberations and 

in the case of RfCs, there have not, to date, been any existing peer-reviewed EPA 

documents. Thus, RfC deliberations are based on extensive assessment summaries 

prepared expressly for the work group. Therefore, when an Agency peer-reviewed 

document is not available, as with RfCs and some RfDs, extensive assessment summaries 

are included on IRIS once the work group has completed verification and reached 

consensus. 

The work group co-chairs assure that the final summary accurately expresses the 

consensus view of the group at the meeting as specified in the meeting notes. Once 

unanimous consensus is reached, the substance-specific summary for either an RfD or 

RfC is prepared for inclusion on IRIS. In some cases, the work group agrees that 

adequate information is not available to derive an RfD or RfC. A message is then put on 

IRIS to that effect and the reasons for the “not verifiable” status. In most cases the 

message states that the health effects data for a specific substance were reviewed by the 

work group and determined to be inadequate for derivation of an RfD or RfC. 

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Conflicts that arise during a meeting regarding a given RfD or RfC generally are 

resolved outside the meeting by scientists from the appropriate offices, and then brought 

back to the work group for clarification and subsequent consensus. Conflicts that arise 

regarding the methods by which RfDs or RfCs are estimated, or the incorporation of new 

methods, are generally taken up at separately scheduled meetings of the work group, for 

which the sponsoring office prepares the appropriate material for review. 

While, as discussed above, the RfD/RfC Work Group process is somewhat 

different from that of the CRAVE, they both use generally the same consensus 

procedures. Other procedural similarities are discussed in the following paragraphs. 

On occasion, scientific issues on individual substances, methods, or on a general 

question cannot be resolved at the work group level. In the event that an issue is 

unresolvable in the work group processes, the issue is referred to the Risk Assessment 

Council. In some cases, the issue is brought to the IRIS Oversight Subcommittee for 

review and discussion, prior to consideration by the full Council. If an issue is raised to 

the Council, it may be referred by the Council to the Risk Assessment Forum for 

consultation. 

Both the CRAVE and RfD/RfC Work Groups, through the IRIS Information 

Submission Desk, discussed in the companion FEDERAL REGISTER notice, have 

received comments and studies from interested parties outside of the Agency that were 

either pertinent to the work group’s initial review or resulted in reconsideration of a 

particular substance assessment. Further, the work groups often contact the authors of 

a primary study if clarifications are necessary, and consult with outside experts on 

scientific issues that require expertise that is not present in the work group. Also, through 

professional societies and other private sector organizations, the work groups have 

fostered discussions and exchanges regarding new and innovative approaches to human 

health assessment methodologies. 

Methods and Guidelines 

Both Agency work groups responsible for the development of the health hazard 

information on IRIS use Agency scientific methods documents and EPA’s risk assessment 

guidelines as the basis for their work. These guidelines and methodologies used to 

develop the RfD or RfC have been peer reviewed by the SAB. 

Summaries of methods used for development of oral RfDs and carcinogenicity 

information on IRIS are contained in IRIS background documents that are available on the 

system. A paper copy of the oral RfD and CRAVE background documents, “Reference 

Dose (RfD); Description and Use in Health Risk Assessment” (Regulatory Toxicology and 

Pharmacology 8:471-486, 1988) and The U.S. EPA Approach for Assessing the Risks 

Associated with Chronic Exposures to Carcinogens, respectively, is also available from 

IRIS User Support by calling: (513) 569-7254. 

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The draft methods document, interim Methods for Development of Inhalation 

Concentrations (EPA/600/8-90/066A), is the basis for the inhalation WCs. A copy of the 

document is available from the Center for Environmental Research Information (CERI) by 

calling: (513) 569-7562. Please cite the EPA document number (EPA/600/8-90/066A) 

when requesting a copy. A revised RfC methodology document based on SAB peerreview comments will undergo a second SAB review and will be available later this year. 

The CRAVE background document is based on EPA’s 1986 Guidelines for 

Carcinogen Risk Assessment (51 FR 33992-34003). A copy of the EPA risk assessment 

guidelines (EPA/600/8-87/045) is also available by calling CERI. 

Public Involvement 

The section in the companion FEDERAL REGISTER notice (February 25, 1993, 

58 FR 11490) on Current Opportunities for Public Involvement in the IRIS Process 

elaborates on opportunities for public input and dialogue. 

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