To complaints by the diesel industry that the new fuel standards will prove impossible to meet, Carol Browner, director of the EPA replied "We don't see any reason why they shouldn't be able to deliver clean diesel fuel." Rich Kassel of the Natural Resources Defense Council said that environmentalists are preparing to meet an expected industry backlash, explaining, "It has become clear to us that some oil companies would rather spend their money on lobbyists than on cleaning up their fuel."

The Clinton administration will hold hearings in June on the proposed regulations, one of them in New York City, followed by a 45-day public comment period. NRDC and other environmental groups have vowed to win an accelerated phase-in of the nitrogen oxide reduction rule, as well as to increase incentives for transit fleets to switch to non-diesel, cleaner fuel alternatives like CNG.

On Monday, the U.S. Department of Health's National Toxicology Program headquartered at the National Institute of Health released the 9th edition of its Report on Carcinogens. In it, diesel exhaust particulates are listed for the first time as "reasonably anticipated to be [a] human carcinogen" from evidence in humans and laboratory animals. The Report, based on three years of exhaustive study and comment, is used as a primary reference by the U.S. Congress, Federal and State agencies, as well as private businesses, labor unions, and the general public.

The Department of Health joins the World Health Organization and the California Air Resource Board, and the EPA who have already sounded the alarm that exposure to components of diesel exhaust increase cancer risks