Committee to Advise on Reassessment and TransitionPaper #8
Cancer Risk Assessment Guidelines Used by OPP
What are Risk Assessment Guidelines?
- EPA has issued, over the past 20+ years, a series of guidance documents that describe the principles, policies, and practices the Agency will employ when evaluating the scientific data on the toxicity of, and exposure to, environmental agents.
- EPA's guidelines cover many topics, including cancer, reproductive and developmental toxicity, mutagenicity, neurotoxicity, ecological effects, mixtures, and exposure.
- EPA's guidelines are meant to be used by Agency risk assessors to assure consistency in the interpretation of scientific information across all Agency programs and regions.
History of EPA's Cancer Risk Assessment Guideline Development
- 1976--EPA issued its initial set of principles to guide the evaluation of the human cancer potential of environmental agents.
- 1986--EPA issued an updated, and significantly more robust, set of guidance.
- 1996 to present-EPA, in light of very significant progress in the state-of-the-science, issued for review and comment proposed revisions to the 1986 guidelines.
- Several meetings of the Science Advisory Board and rounds of public comment have occurred, the most recent in July,1999, which focused on issues related to children's risk.
- In 1998/1999, additional concepts were introduced into the guidelines, including:
- The Mode-of-Action (MOA) framework, an analytic structure to assist in "ordering" information in a useful and transparent manner, in order to reach conclusions about whether or not the available data are sufficiently robust to describe the mode or modes of action at play in the cancer responses observed and to identify data gaps.
- A discussion--expanding on, but consistent with, the 1986 and the April 1996 versions--on what the Agency would do with respect to dose response assessment (i.e., linear, non-linear, or both), depending upon the outcome of the MOA analysis.
- Proposed guidance on how to interpret information, describe carcinogenic potential, etc., as it specifically pertains to children. (The report from the July meeting will be taken up by the SAB Executive Committee on June 16. At that time, the Agency will find out if the Executive Committee accepts the draft report, or asks that additional work be done. Their advice will contribute to the determination of the time line for completion of the revision activities.)
OPP's Use of the Cancer Guidelines
- OPP announced in Pesticide Registration (PR) Notice 96-5 that it would begin applying elements of the draft proposed revised guidelines after they were issued for comment in April 1996. None of those practices are in conflict with the principles articulated in the 1986 guidelines.
- Among the "new" practices was the use of a new default interspecies scaling factor (this Agency-wide change, in fact, preceded the revised guidelines, in light of cross-government deliberations and agreements reached in 1992).
- In addition, OPP (and, the Agency) abandoned dependence upon the use of the short-hand Group A-E weight-of-evidence classification scheme in favor of the more detailed and transparent five-category descriptor scheme for characterizing human cancer potential, while also considering the necessity of making exposure-route-specific (i.e., oral, dermal, inhalation) determinations.
- Since 1996, OPP has moved to consider additional aspects of each area as it has been fully described, particularly those aspects where there appears to be consensus. None of these practices are in conflict with the principles articulated in the 1986 guidelines.
- To reduce confusion regarding which version(s) of the guidelines may have been considered in a specific case, one needs to take careful note of the time frame(s) in which these chemical-specific assessments were conducted.
For more information:
EPA's 1999 Proposed Guidelines for Carcinogen Risk Assessment are available at http://www.epa.gov/ncea/cancer.htm.
Contact the National Pesticide Telecommunications Network 800-858-7378; http://npic.orst.edu for information on the toxicity of pesticides.
- EPA's pesticide homepage www.epa.gov/pesticides has information about pesticide regulation as well as publications about pesticide issues for consumers.