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Integrated Risk Information System (IRIS); Announcement of 2004 Program; Request for Information

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Environmental Protection Agency.


Notice; announcement of IRIS 2004 program agenda and request for scientific information on human health effects that may result from exposure to chemical substances.


The Environmental Protection Agency (EPA) is announcing the IRIS 2004 agenda and requesting scientific information on health effects that may result from exposure to the chemical substances for which EPA is starting assessments this year.

The Integrated Risk Information System (IRIS) is an EPA data base that contains the Agency's scientific consensus positions on human health effects that may result from exposure to chemical substances in the environment. On February 5, 2003 (68 FR 5870) and later supplemented on August 13, 2003 (68 FR 48359), EPA announced the 2003 IRIS agenda, with the solicitation of scientific information from the public for consideration in assessing health effects from specific chemical substances. Many of these assessments are on-going or near completion. All assessments completed in FY03 and early FY04 are listed in this notice. This notice also describes some of EPA's efforts to improve the IRIS program.


Please submit any scientific information in response to this notice in accordance with the instructions provided at the end of this notice by April 9, 2004.


Please submit relevant scientific information identified by docket ID number ORD-2003-0016, online at​edocket (EPA's preferred method); by e-mail to; mailed to EPA Docket Center, Environmental Protection Agency, Mailcode: 2822T, 1200 Pennsylvania Ave., NW., Washington, DC 20460-0001; or by hand delivery or courier to EPA Docket Center, EPA West, Room B102, 1301 Constitution Ave., NW., Washington, DC, between 8:30 a.m. and 4:30 p.m. Monday through Friday, excluding legal holidays. Comments on a disk or CD-ROM should be formatted in Wordperfect or ASCII file, avoiding the use of special characters and any form of encryption, and may be mailed to the mailing address above.

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For information on the IRIS program, contact Amy Mills, Program Director, National Center for Environmental Assessment, (mail code 8601D), Office of Research and Development, U.S. Environmental Protection Agency, Washington, DC 20460; telephone: (202) 564-3204, facsimile: (202) 565-0075; or e-mail:

For general questions about access to IRIS, or the content of IRIS, please call the IRIS Hotline at (202) 566-1676 or send electronic mail inquiries to

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IRIS is an EPA data base containing Agency scientific positions on potential adverse human health effects that may result from exposure to chemical substances found in the environment. IRIS currently provides information on health effects associated with more than 500 chemical substances.

The data base includes chemical-specific summaries of qualitative and quantitative health information in support of the first two steps of the risk assessment process, i.e., hazard identification and dose-response evaluation. Combined with specific situational exposure assessment information, the information in IRIS may be used as a source in evaluating potential public health risks from environmental contaminants.

EPA's overall process for developing IRIS assessments consists of: (1) An annual Federal Register announcement of EPA's IRIS agenda and call for scientific information from the public on selected chemical substances; (2) a search of the scientific literature; (3) development of IRIS summaries and support documents; (4) agency review; (5) external peer review; (6) management review and approval; (7) entry of IRIS summaries and support documents into the IRIS data base (​iris).

The IRIS Annual Agenda

Each year, EPA develops a list of priority chemical substances and an annual agenda for the IRIS program. EPA uses four general criteria to set these priorities: (1) EPA statutory, regulatory, or program-specific implementation needs; (2) availability of new scientific information or methodology that might significantly change the current IRIS information; (3) interest to other levels of government or the public; and (4) availability of other Start Printed Page 5972scientific assessment documents such that only a modest additional effort would be needed to complete the review and documentation for IRIS. The decision to assess any given chemical substance hinges on available Agency resources. Availability of risk assessment guidance, guidelines, and science policy decisions may also have an effect on the timing of EPA's decision to assess a chemical substance.

Consistent with previous Federal Register notices announcing the annual IRIS agenda, EPA is soliciting public involvement in new assessments starting in FY 2004. While EPA conducts a thorough literature search for each chemical substance, there may be unpublished studies or other primary technical sources that we may not otherwise obtain through open literature searches. We would appreciate receiving scientific information from the public during the information gathering stage for the list of “new assessments” provided in this notice. Interested persons should provide scientific analyses, studies, and other pertinent scientific information. Also note, if you have submitted information previously to the IRIS Submission Desk, there is no need to resubmit that information. While EPA is primarily soliciting information on new 2004 assessments announced in this notice, the public may submit information on any chemical substance at any time.

This notice provides: (1) A list of the IRIS assessments completed in FY 2003 and early FY 2004; (2) a list of the IRIS assessments in progress that the Agency expects to complete in FY 2004-2005; (3) a list of IRIS assessments requiring a more extensive effort; (4) a list of IRIS assessments deleted from the 2003 agenda; (5) a list of new IRIS assessments starting in FY 2004; (6) a new approach to systematically update IRIS; (7) an announcement of improvements underway to the IRIS program; and (8) instructions to the public for submitting scientific information to EPA pertinent to the development of IRIS assessments.

Assessments Completed in Late FY 2003 and Early FY 2004

The following assessments were completed and entered into IRIS in FY 2003 and early FY 2004. These assessments were listed in the Federal Register of February 5, 2003 (68 FR 5870). All health endpoints associated with chronic exposure, cancer and noncancer, were assessed unless otherwise noted. Where information was available, both qualitative and quantitative assessments were developed.

Substance nameCAS No.
Benzene (noncancer)71-43-2
Dichloroacetic acid79-43-6
Diesel engine exhaust[N.A.]
Hydrogen sulfide7783-06-4
Methyl ethyl ketone78-93-3
Methyl isobutyl ketone108-10-1

Assessments in Progress

The following assessments are underway or generally complete, and are planned for entry into IRIS in FY 2004 or FY 2005. All health endpoints due to chronic exposure, cancer and noncancer, are being assessed unless otherwise noted. For all endpoints assessed, both qualitative and quantitative assessments are being developed where information is available.

Substance nameCAS No.
Aldicarb/Aldicarb sulfoxide116-06-3/1646-87-3
Aldicarb sulfone1646-88-4
Beryllium (cancer effects)7440-41-7
Carbon tetrachloride56-23-5
Chloroform (inhalation route)67-66-3
Dibutyl phthalate84-74-2
Di(2-ethylhexyl)adipate (DEHA)103-23-1
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Ethylene dibromide106-93-4
Ethylene dichloride107-06-2
Ethylene glycol monobutyl ether (cancer effects)111-76-2
Hydrogen cyanide74-90-8
Methylene chloride (Dichloromethane)75-09-2
Naphthalene (cancer effects; inh. route)91-20-3
Nickel (soluble salts)[N.A.—various]
PAH mixtures[N.A.—various]
Perfluorooctanoic acid—ammonium salt3825-26-1
Perfluorooctane sulfonate—potassium salt2795-39-3
Phosgene (acute exposure; inhalation route)75-44-5
Polybrominated diphenyl ethers (PBDEs):[N.A.—various]
Refractory ceramic fibers[N.A.]
Trichloroacetic acid76-03-9
Uranium (natural)7440-61-1
Vinyl acetate108-05-4
Zinc and compounds7440-66-6

Update of the 2003 IRIS Agenda

EPA has taken active steps to reconsider and update the list of chemical substances on the 2003 IRIS agenda to better reflect the assessments currently underway and corresponding time frames for completion. To that end, EPA has carefully reviewed the chemical assessments on the 2003 agenda and determined that some will need more time for completion due to a higher level of complexity. Highly complex assessments often lead EPA to identify new research needs, apply new methodologies, or conduct multiple, in-depth, high level external scientific peer reviews to ensure the application of sound science. The following chemical assessments will therefore require a more extensive effort.

Substance nameCAS No.
Ammonium Perchlorate (and other perchlorate salts)7790-98-9
Arsenic, inorganic7440-38-2
Asbestos (noncancer effects)1332-21-4
Ethylene oxide (cancer effects)75-21-8
Methyl tert-butyl ether (MTBE)1634-04-4
Tetrachloroethylene (perchloroethylene)127-18-4
Polychlorinated biphenyl (PCBs-noncancer endpoints)1336-36-3
2,3,7,8-TCDD (dioxin)1746-01-6

In addition, anticipation of new data, emerging methodology, or lack of immediate Agency resources provide the basis for placing the following chemical assessments on a longer time frame for completion. This includes substances denoted with an asterisk (*), which are being evaluated for effects from acute and/or other less-than-lifetime exposure durations. These substances are part of a pilot test to evaluate the application of methods, procedures, and resource needs for adding health effects information for less-than-lifetime exposure duration to IRIS. This effort was announced in the February 5, 2003 (68 FR 5870) Federal Register.

Substance nameCAS No.
Dibutyl phthalate*84-74-2
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Ethylene oxide*75-21-8
Hexahydro-1,3,5-trinitro-triazine (RDX)121-82-4
Hydrogen sulfide*7783-06-4

Assessments Deleted From the IRIS Agenda

EPA is deleting from the IRIS agenda a group of pesticides that will not be assessed through the IRIS process. This step is being taken to more efficiently utilize Agency resources, given that the Office of Pesticide Programs (OPP) has a large assessment program evaluating these chemicals. Under the 1996 Federal Insecticide, Fungicide, and Rodenticide Act (FIFRA), EPA requests relevant scientific data from pesticide registrants and develops health assessments based on that information. EPA is considering the means for providing electronic public access to pesticide assessments conducted under FIFRA. The following pesticides listed in the February 5, 2003 (68 FR 5870) Federal Register are therefore removed from the IRIS agenda for FY2004.

Substance nameCAS No.
Azinophos methyl86-50-0
Methyl parathion298-00-0

In addition to these pesticides, EPA will remove Silica (crystalline) (CAS No. 14808-60-7), and Antimony and compounds (7440-36-0) due to limited EPA resources and lower overall priority at this time.

IRIS summaries and support documents for all substances listed as on-going assessments in FY 2004 will be provided on the IRIS Web site at​iris as they are completed. This publicly available Web site is EPA's primary location for IRIS documents. In addition, external peer review drafts of IRIS documents can be found during their peer review periods via the “What's New” page of the IRIS Web site. Interested parties should check the “What's New” page frequently for the availability of these drafts.

Information Requested on New Assessments for FY 2004

EPA will continue building and updating the IRIS data base. The Agency recognizes that a number of the assessments on IRIS need updating to incorporate new scientific information and methodologies. Further, many additional substances are candidates for adding to IRIS. However, due to limited resources in the Agency to address the spectrum of needs, EPA developed a list of priority substances for attention beginning in FY 2004 based on specific criteria.

EPA developed the list of priority substances for FY 2004 by sorting chemical nominations from the EPA programs and the public according to the following considerations: (1) Multiple nominations were received for a chemical in response to the August 2003 FRN requesting nominations (68 FR 48359); (2) a nomination met multiple criteria among (a) statutory, regulatory or programmatic need, (b) interest to other levels of government or the public, and (c) availability of other assessment documents for use in developing an IRIS assessment. To refine the list of nominations meeting multiple criteria, high priority was given to EPA programs' priority nominations; (3) significant new health effects information is available on which to base an assessment; and (4) Agency resources are available to conduct the assessment. Available health effects information and EPA resources are considered critical for selecting a chemical for assessment. EPA's priority-setting approach for the IRIS agenda was discussed at a public stakeholder workshop, announced in the February 5, 2003 FRN (68 FR 5870) and held on March 4, 2003. The primary recommendation from this workshop was that EPA should be more transparent in explaining why Start Printed Page 5975chemicals are selected for the IRIS agenda by providing a specific rationale for each selection. EPA's rationales are therefore given below.

Based on EPA's prioritization process described above, the following IRIS health assessments have been selected for start up in FY 2004, with completion expected in FY 2006. The Agency is requesting information from the public for consideration in the development of these assessments. For all endpoints assessed, both qualitative and quantitative assessments will be developed where information is available.

Substance nameCAS No.Reason
1,2-Dichloroethylene540-59-0RCRA hazard identification and corrective action need. New scientific information is available to update IRIS.
1,4-Dioxane123-91-1CERCLA site cleanup need. New scientific information is available to update IRIS. Public interest.
Ethyl tertiary butyl ether637-92-3CAA and SDWA need. Scientific information is available.
Lead (update qualitative discussion)7349-92-1CERCLA and RCRA site cleanup need. New scientific information is available to update IRIS. Public interest.

Systematic Update of IRIS Data Base

While the annual prioritization process responds to the needs expressed by IRIS users, EPA is also systematically updating the IRIS data base. The IRIS Program has conducted a screening-level review of the available scientific literature for all chemicals in the IRIS data base. The purpose of EPA's screening level review was to reach preliminary determinations regarding the likelihood that a full reassessment based on an evaluation of new health effects literature could potentially result in significant changes to existing toxicity values or cancer weight-of-evidence designations. The process consisted of a preliminary search and review of the literature through standard toxicological bibliographic data bases (titles and abstracts) and selected literature compilations to identify new major studies that have become available since the existing IRIS assessment was completed. Screening-level reviews were completed for 460 chemicals in the IRIS data base, that is, essentially all chemicals in the data base with the exception of those that are on the current IRIS agenda and are being fully reassessed. For 291 of the 460 chemicals reviewed (about 60%), no major new health effects studies were found that would be likely to significantly change existing toxicity values. These findings have been added to the “EPA Review and Documentation” sections of each individual IRIS Summary.

EPA plans to use findings from this literature screen as a basis for systematically updating IRIS by performing a more in-depth review of the extant health data. This more in-depth review will seek to confirm results from the IRIS literature screening review. For those chemicals confirmed to be without new health information to change the existing assessment, EPA will update IRIS summaries to indicate the currency of scientific information upon which the assessment was based.

We are requesting the submission of any scientific information that you would like EPA to consider in confirming the results of the literature screening review. You can locate the screening-level literature review findings for a chemical assessment on the IRIS Web site (​iris) by selecting the specific chemical summary of interest and scrolling down to the “EPA Documentation and Review” section of the reference dose, reference concentration, and cancer assessments.

Improvements to the IRIS Program

EPA has taken steps to improve the timeliness, quality, transparency, and consistency of IRIS assessments through a series of program reforms. EPA has plans to expand its central IRIS Staff to better manage the program and ensure scientific quality and consistency. In addition, the IRIS program will conduct more of its external scientific peer reviews by panel meetings rather than by mail reviews. This step is being taken to provide the best possible scientific review of each assessment. In addition, panel peer review meetings are open to the public for observation, making the review process more transparent. Further, EPA is now positioning the external peer review step at the end of the IRIS assessment review process, strengthening the role of peer review in informing EPA's final decision-making. Future funding levels, when provided by Congress, may affect actual program implementation and the resulting numbers of assessments completed and/or initiated.

General Information

A. How Can I Get Copies of Related Information?

EPA has established an official public docket for this action under Docket ID No. ORD 2003-0016. The official public docket is the collection of materials that is available for public viewing at the Office of Environmental Information (OEI) Docket in the EPA Docket Center, EPA West, Room B102, 1301 Constitution Ave, NW., Washington, DC. The EPA Docket Center Public Reading Room is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the OEI Docket is (202) 566-1752.

An electronic version of the public docket is available through EPA's electronic public docket and comment system, EPA Dockets. You may use EPA Dockets at​edocket/​ to submit or view public submissions, access the index listing of the contents of the official public docket, and to access those documents in the public docket that are available electronically. Once in the system, select “search,” then key in the appropriate docket identification number.

It is important to note that EPA's policy is that public submissions, whether submitted electronically or in paper, will be made available for public viewing in EPA's electronic public docket as EPA receives them and without change, unless the submission contains copyrighted material, CBI, or other information whose disclosure is restricted by statute. Information claimed as CBI and other information whose disclosure is restricted by statute is not included in the official public docket or in EPA's electronic public docket. EPA's policy is that copyrighted material, including copyrighted material contained in a public comment, will not be placed in EPA's electronic public docket but will be available only in printed, paper form in the official public docket. Although not all docket materials may be available electronically, you may still access any of the publicly available docket Start Printed Page 5976materials through the EPA Docket Center.

B. How and To Whom Do I Submit Scientific Information?

You may submit scientific information as provided in the ADDRESSES section. Please submit scientific information within 60 days of this notice, provide all information (studies, reports, articles, etc.) you wish to submit. Please ensure that your submissions are submitted within the specified period. Information received after the close of the submission period will be marked “late.” Late submissions may be considered if time permits. Your submission should specify the chemical substance to which your information pertains, CASRN (Chemical Abstract Service Registry Number), and the topic or aspect of the assessment that is being addressed (e.g., carcinogenicity, mode of action). In addition, when you submit results of new health effects studies concerning existing substances on IRIS, you should include a specific explanation of how the study results could change the information in IRIS. All citations should be listed in scientific citation format, that is, author(s), title, journal, and date. Include names, addresses and telephone numbers of person(s) to contact for additional information.

If you submit electronic information, EPA recommends that you include your name, mailing address, and an e-mail address or other contact information in the body of your submission and with any disk or CD ROM you submit. This ensures that you can be identified as the submitter of the information and allows EPA to contact you in case EPA cannot read your information due to technical difficulties or needs further information on the substance of your submission. Any identifying or contact information provided in the body of submitted information will be included as part of the submission information that is placed in the official public docket, and made available in EPA's electronic public docket. If EPA cannot read your information due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your information.

Your use of EPA's electronic public docket to submit information to EPA electronically is EPA's preferred method for receiving submissions. The electronic public docket system is an “anonymous access” system, which means EPA will not know your identity, e-mail address, or other contact information unless you provide it in the body of your submission. In contrast to EPA's electronic public docket, EPA's electronic mail (e-mail) system is not an “anonymous access” system. If you send e-mail directly to the Docket without going through EPA's electronic public docket, your e-mail address is automatically captured and included as part of the submission that is placed in the official public docket, and made available in EPA's electronic public docket.

You may also request to augment your submission with a scientific briefing to EPA staff. Such requests should be made directly to Amy Mills, IRIS Program Director (see For Further Information).

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Dated: February 3, 2004.

Peter Preuss,

Director, National Center for Environmental Assessment.

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[FR Doc. 04-2711 Filed 2-6-04; 8:45 am]