EPA Seeks Comments on Dioxin Cleanup Goal

The U.S. Environmental Protection Agency has opened public comment on the Office of Solid Waste and Emergency Response's (OSWER) plan for developing interim recommended preliminary remediation goals for dioxin.

In May, EPA Administrator Lisa P. Jackson decided that the agency needs to accelerate work under way to reassess the human health risks from exposures to dioxin.

The agency's Science Plan for Activities Related to Dioxins in the Environment (2009) details a plan, with interim milestones, for completion of the dioxin reassessment. By the end of 2010, EPA expects to complete the reassessment and release it to the public, subject to further consideration of the science and the scope and complexity of the revisions that will need to be made.

Several key site-specific decisions involving dioxin may need to be made before the reassessment is finalized. OSWER will be reviewing current dioxin cleanup guidance, with the goal of recommending interim preliminary remediation goals (PRGs) informed by the latest science. These interim recommended PRGs would be used until EPA issues its dioxin reassessment and OSWER issues final recommended PRGs based on the reassessment. After publication of the dioxin reassessment and final PRG guidance, EPA will re-evaluate clean-up decisions at Superfund, federal facilities, brownfields, and Resource Conservation and Recovery Act sites that were based on the interim PRGs to ensure that cleanups are protective. Current PRGs for these sites are 1 ppb (part per billion) for dioxin toxicity equivalents in residential soil, and a level within the range of 5 ppb and 20 ppb in commercial/industrial soil, where exposure is due to direct contact.

In developing these interim recommended PRGs, OSWER and EPA’s Office of Research and Development are reviewing current soil clean-up levels and dioxin toxicity values used by the states, the Agency for Toxic Substances and Disease Registry, and other countries. Based on this evaluation, OSWER may reconsider EPA’s currently recommended PRGs. Three key components of the current recommended PRGs will be re-evaluated:

  • the EPA dioxin toxicity value adopted in 1985,
  • generic exposure assumptions, and
  • the cancer risk level.

Interim recommended PRGs are scheduled for public comment in the Federal Register on Dec. 31, 2009

EPA will make this information available to the public through its Superfund Web site; Clu-in, a Web site maintained by EPA that has technical information related to cleanups; postings on regional Web sites and used at public meetings; and distribution generally to the regions.

To comment on the proposed plan for developing interim recommended PRGs for dioxin in soil, send comments to OSWER_Dioxin_PRGs@epa.gov.

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