Research associate, research fellow American Museum Natural History, 1958-1965. Faculty department biology Queens College, City University of New York, New York City, 1965-1981. Professor emeritus, since 1981.
Partner, head science causation team Rivkin, Radler & Kremer, Uniondale, New York, 1981-1992, of counsel, since 1993. Appointed member United States Department of Agriculture Agriculture Biotechnology Research Advisory Commission, 1992, member national areas management advisory committee, since 1994. Chairman legal section 1st International Congress on Environmental Information, 1989, 92.
Chairman litigation section 10th International Meeting on Dioxin, 1990.
With United States Army, 1955-1957. Member American Association for the Advancement of Science, American Bar Association, American Association for Clinical Chemistry, American Chemical Society (chairman torts group 1989-1990), American College Toxicology, American Microscopical Society, Defense Research Institute, Florida Bar Association, New York Academy of Sciences, New York State Bar Association, Palm Beach Bar Association, Sigma Xi.