President Trump has made a habit of filling important jobs with people dedicated to undermining the laws they’re supposed to administer while pampering the industries they’re supposed to regulate. His nominee for the Environmental Protection Agency’s top clean air post, William Wehrum, is a retread from the George W. Bush administration with a deep doctrinal dislike of clean air regulations. His choice to run the White House Council on Environmental Quality is borderline comical: Kathleen Hartnett White, a former Texas official who believes that the main greenhouse gas, carbon dioxide, is harmless. Yet no nomination has been as brazen, as dangerous to public health and as deserving of Senate rejection as that of Michael Dourson to run the E.P.A. office in charge of reviewing chemicals used in agriculture, industry and household products.

Mr. Dourson is a scientist for hire. A toxicologist and a professor at the University of Cincinnati, he has a long history of consulting for chemical companies and conducting studies paid for with industry money. He frequently decided that the compounds he was evaluating were safe at exposure levels that are far more dangerous to public health than levels recommended by the E.P.A., the Centers for Disease Control and Prevention and other agencies. His nomination is enthusiastically endorsed by the chemical industry. It horrifies environmental groups, public health advocates, firefighters and scientists and has inspired many letters in opposition to the Senate Environment and Public Works Committee, which may vote as early as Wednesday.

Among the chemicals that received a favorable nod from Mr. Dourson is 1,4-dioxane, which is used by paint and coating manufacturers and is also found in shampoos and other personal care products. His analysis recommended a safe level that was 1,000 times higher than the E.P.A.’s recommended level; the agency considers the chemical “a likely carcinogen.”

Another is PFOA, a chemical used by DuPont to make nonstick surfaces. The compound has been linked to cancers, thyroid diseases and other health problems. Working for West Virginia on the recommendation of DuPont, Mr. Dourson in 2002 helped establish a safety threshold of 150 parts per billion for PFOA in drinking water. That is substantially higher than the standard of 1 part per billion that DuPont’s own scientists had recommended more than a decade earlier, and higher still than the health advisory level of 0.07 parts per billion set by the E.P.A. last year.