EPA Issues New Risk Assessment Guidance

June 15, 2002

Agency guidance provides direction on probabilistic analysis ," The U.S. Environmental Protection Agency (EPA) finalized guidance addressing the use of probabilistic risk assessments at Superfund sites. The guidance provides direction on applying probabilistic analysis to both human health and ecological risk assessments. Probabilistic risk assessments use probability models to incorporate uncertainty and variability or the likelihood of different risk levels in a population into human health and ecological risk assessments. A traditional assessment, or point estimate assessment, is similar but cannot characterize uncertainty and variability. A risk assessment is an integral part of any remedial investigation and feasibility study for a Superfund site. The risk assessment generally is conducted to determine the need for action and to ensure the selected remedy will protect human health and the environment, based on the level of risk identified in the assessment. The addition of probabilistic analysis to risk assessments is part of EPA's project to update all existing risk assessment guidance for the Superfund program. The use of assessments by responsible parties and others remains discretionary. The final guidance contains only minor changes to the draft guidance issued in February 2000. The final guidance is available at www.epa.gov/superfund/programs/risk/rags3adt/index.htm.

NESHAP proposed for certain chemical, coating manufactures ," EPA proposed national emission standards for hazardous air pollutants (NESHAP) for the Miscellaneous Organic Chemical Manufacturing and the Miscellaneous Coating Manufacturing source categories. The agency determined that both source categories are major sources of hazardous air pollutants (HAPs) such as toluene, methanol, xylene, hydrogen chloride and methylene chloride. The proposed NESHAP would implement Section 112(d) of the Clean Air Act by requiring all major sources in the two source categories to meet HAP emission limitations and put into place work practice standards reflecting the application of maximum achievable control technology (MACT). According to EPA, subparts FFFF and HHHHH of the proposed rule would combine to slash HAP emissions by approximately 37,150 tons per year. For more information, see the Federal Register notice at www.epa.gov/fedrgstr/EPA-AIR/2002/April/Day-04/a5077a.htm.

TCE assessment review set for June ," EPA identified 22 potential representatives to serve on its Science Advisory Board to review the agency's draft assessment of trichloroethylene (TCE), Trichloroethylene Health Risk Assessment: Synthesis and Characterization. Panelists selected from this "short list" will review the draft health assessment at a public meeting this month in Washington, D.C. The draft TCE health assessment, released in September 2000, assesses health risks of TCE, examining the possibility that certain groups are more susceptible to its harmful effects and addressing cumulative risks. Certain chemical and defense industry groups believe the draft assessment provides an exaggerated depiction of risks. These groups fear that unnecessary high-cost cleanup actions will be required if EPA's conclusions are accepted. TCE, a commonly used solvent, is a contaminant in air, soil and water. According to EPA, TCE is present at approximately 60 percent of Superfund sites. It is the most frequently reported organic contaminant in groundwater, says EPA, and is one of the top carcinogens released and reported to the Toxic Release Inventory. The names of the potential panel members and brief biographies are available at www.epa.gov/sab/tcepanel.html.

President Bush takes action on toxics ," EPA recently announced that President Bush is submitting the Stockholm Convention on Persistent Organic Pollutants (POPs) to the U.S. Senate for advice and ratification. The United States signed the treaty in May 2001. The Stockholm Convention targets 12 toxic chemicals that persist in the environment for long periods of time, accumulate in the food chain and travel great distances. The 12 POPs include certain pesticides, industrial chemicals and unintended byproducts of combustion such as dichlorodiphenyltrichloroethane (DDT), polychlorinated biphenyls (PCBs) and dioxin. The convention is intended to eliminate or restrict the production, use and/or release of the 12 targeted chemicals. The convention obligates all participating countries to take measures to eliminate or to restrict the production, use and trade of intentionally produced POPs; to develop action plans to address the release of byproduct POPs (such as using best available techniques to reduce emissions of POPs from new sources); and to address the safe handling and disposal of POPs stockpiles and wastes. More information about the Stockholm Convention and POPs is available at http://irptc.unep.ch/pops/.

Grayson is a partner with Jenner & Block, Chicago, working in the firm's Environmental Law practice group, www.jenner.com/practice/environ/environ.html. Contact her via e-mail at [email protected].

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