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2012 EPA Research Progress Report

Growing IRIS: Advancing EPA's Integrated Risk Information System

IRIS is a human health risk assessment program through which Agency scientists evaluate and present comprehensive risk information on the health effects that may result from exposures to contaminants in land, water, and air.

EPA researchers provide leadership to assess the potential health effects posed by exposures to chemicals in the environment. A critical part of that effort is the Agency’s Integrated Risk Information System, or “IRIS.”

IRIS is a human health assessment program through which Agency scientists evaluate and present comprehensive information on the health effects that may result from exposures to contaminants in land, water, and air.

IRIS health assessments provide information on the hazards a chemical may pose as well as information on “dose-response” (the relationships between amounts of exposure and expected effects), resulting in reference doses, reference concentrations, cancer slope factors, and inhalation unit risks. When combined with information about people’s environmental exposure to a chemical, IRIS assessments can be used to characterize health risks.

Strengthening IRIS

Because of the critical importance of IRIS for the supporting EPA and beyond, a strong, vital and scientifically sound program is key to providing needed health risk information. Over the past two years, EPA has worked to strengthen and streamline the IRIS program, improving transparency and increasing the number of final assessments added to the IRIS database. Continually improving IRIS is a priority for the Agency, and efforts are underway to further strengthen and streamline this important program.

IRIS assessments are not full risk assessments or regulations, however, they provide part of the scientific foundation that supports Agency decisions and actions for the nation’s environmental laws, and are widely used throughout the country on the federal, state, and local levels to guide cleanup and other actions to protect human health.

Currently, IRIS contains information on more than 560 chemicals.

Over the past few years, EPA has taken steps to significantly improve the IRIS program. Those efforts continued throughout 2012.

On June 5, 2012, EPA publicly released an IRIS progress report to the U.S. Congress (PDF) (29 pp, 1.3Mb) (EPA’s Integrated Risk Information System Program, Progress Report and Report to Congress, U.S. Environmental Protection Agency). The report provided Congress, stakeholders, and the public with an update on the program, and on EPA’s progress toward implementing recommendations to improve the program made by the National Research Council (NRC) in 2011.

Improvements were illustrated further with the release of the 2012 draft assessments for ammonia (IRIS Toxicological Review of Ammonia, External Review Draft, U.S. Environmental Protection Agency) and several isomers of trimethylbenzene (IRIS Toxicological Review of Trimethylbenzenes, External Review Draft,. U.S. Environmental Protection Agency).

The assessments present a new, highly improved document structure which includes a template for describing the literature search approach used in the assessments. In addition, the documents clearly identify the strengths and weaknesses of the analyzed studies and explicitly describe how EPA guidance, methods and criteria were applied in developing the assessments.

Continuing the Agency’s commitment to improving the IRIS program, on May 16, 2012, EPA announced that the NRC would conduct a comprehensive review of the IRIS program’s assessment development processes, review current methods for integrating data, and recommend approaches for weighing scientific evidence for chemical hazard identification.

For more information on the IRIS program, including opportunities to engage with EPA, please visit the IRIS website.

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