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This evidence should be reassuring both to the agricultural community and to the general public that the uses of EBDC products have caused no significant injury to man or the environment and create no substantial risk of such injury. While we applaud the conclusion of the RPAR and the findings of need for and benefits from EBDC products, we reject the EPA risk assessment. In making its assessment, EPA has ignored or cursorily dismissed substantial evidence of the safety of EBDC products and has adhered to a risk analysis which is not relevant to the effect of EBDC uses and is not applicable to the best evidence of their safety. The EPA mathematical risk analysis is not supported by the preponderance of evidence in the record. Reliance upon it has compelled EPA to reject direct probative evidence of the safety of the uses of EBDC products and limited that Agency to reliance upon the predictive value of data on the incidence of liver tumors in cancer prone mice -- a reliance which has been questioned by eminent pathologists and toxicologists and by the EPA itself.

Eliot Marshall's article, "EPA's High-Risk Cancer Policy" (Science,
Dec. 1982) was accompanied by a commentary on recent Environmental Protection
Agency (EPA) decisions, "The Odds on Cancer; EPA's Recent Bets." EPA's recent
favorable decision regarding the continued use of ethylene bisdithiocarbamate
(EBDC) fungicides was included to support the author's argument that EPA
tolerates higher risks to man than it has previously. However, examination of
the data available to EPA as well as a consensus among world experts support
EPA's decision.

The EPA mathematical risk assessment is not supported by the preponderance of evidence in the record. Reliance upon this risk assessment would have compelled EPA to reject direct probative evidence of the safety of the uses of KBDC products and would have limited the agency to reliance upon the predictive value of data on the incidence of liver tumors in cancer prone nice — a reliance which has been questioned not only by eminent pathologists and toxicologists but by the EPA itself.

EPA was fully justified in allowing the continued use of EBDC's as crop fungicides based upon the data available to the Agency. This decision was similar to and consistent with assessments made earlier by the International Union of Pure and Applied Chemistry (IUPAC), Groupement International Association Rationales de Fabricants de Produicts Agrochemiques (GIFAP), and the Food and Agriculture Organization (FAO) of the United Nations.

The following salient points are essential in evaluating the safe use of EBDC's and ethylenethiourea (ETU), the major metabolic and decomposition product of concern.

EBDC's fungicides have been used extensively in the US and abroad for almost forty years. There have been no episodes of significant injury to man or the environment associated with their use.

Dr. P. H. Abelson

December 21, 1982
Page Two

O Epidemiological studies of EBDC production workers show no adverse health effects including effects on thyroid function at levels of exposure significantly higher than those experienced by agricultural workers. O Analyses of foods from the market, and of complete meals from homes and restaurants, sampled on a statistical basis, give a realistic measure of the dietary exposure of the US population to EBDC and ETU residues. Residues on agricultural products are consistently below tolerances. Moreover it appears that general practices, particularly washing, in food preparation and processing in homes, restaurants, and commercial food processing plants remove virtually all residues on food before it is consumed. Results of such analyses bear no relation to theoretical projections based on residue tolerances, which were used in EPA's worst case assessment.

They are

O Neither EBDC products nor ETU are ubiquitous. biodegradable, and will not accumulate, persist, or accrue to significant levels in man or the environment.

O From the actual exposure and published no-effect levels, it was shown that the safety factors are very large for even the sensitive physiology indicator thyroid hyperplasia. Moreover, induction of thyroid hyperplasia is a secondary effect caused by prolonged administration at high pharmacological antithyroid doses. ETU, like related thiourea derivatives used therapeutically, reduces synthesis of thyroid hormones by inhibiting the oxidation of inorganic iodide. Characteristically, continuous, therapeutic dosages are needed to affect thyroid function.

Thus, examination of the data and the opinion of world experts support the conclusion that the EBDC fungicides do not pose an unacceptable carcinogenic or other health risk.

Sincerely,

Sony

Jerry M. Smith, Ph.D., D.A.B.T.
Director of Toxicology Department
Rohm and Haas Company

JMS/bad

Risk

Assessment in the Federal Government: Managing

the Process

Committee on the Institutional Means for Assessment of Risks to Public Health

Commission on Life Sciences

National Research Council

NATIONAL ACADEMY PRESS

Washington, D. C. 1983

Summary

SETTING

This report explores the intricate relations between science and policy in a field that is the subject of much debate--the assessment of the risk of cancer and other adverse health effects associated with exposure of humans to toxic substances. It is a report of a search for the institutional mechanisms that best foster a constructive partnership between science and government, mechanisms to ensure that government regulation rests on the best available scientific knowledge and to preserve the integrity of scientific data and judgments in the unavoidable collision of the contending interests that accompany most important regulatory decisions.

Many decisions of federal agencies in regulating chronic health hazards have been bitterly controversial. The roots of the controversy lie in improvements in scientific and technologic capability to detect potentially hazardous chemicals, in changes in public expectations and concerns about health protection, and in the fact that the costs and benefits of regulatory policies fall unequally on different groups within American society.

The decade of the 1970s was a period of heightened public concern about the effects of technology on the environment. Individuals and groups urged strict government regulation as scientific evidence emerged that various chemical substances may induce cancers or other chronic health effects in humans, and new government programs were established to control potential hazards. The evidence of health effects of a few chemicals, such as asbestos, has been clear; in many more cases the evidence is meager and indirect. To aid decision-making,