An Environmental Protection Agency official, contradicting his boss before a congressional hearing, yesterday said the administration is "underprotective" of the public and has changed the guidelines for regulating carcinogens "to give them a slant which is consistent with the philosophy" of the administration.

Roy Albert, chairman of the EPA's Carcinogen Assessment Group, made his comments only minutes after John Todhunter, the head of EPA's pesticide and toxic substances program, told a House Agriculture subcommittee that the administration has not changed the government's policy on carcinogens.

"I don't believe there has been a change so much as a continuing evolution," Todhunter replied when Rep. George E. Brown Jr. (D-Calif.) queried him about figures Brown had compiled on the Reagan EPA's record. Brown said the number of EPA staffers working in the pesticides and toxic substances area has dropped from more than 760 to less than 540 over the past three years, and more cuts are scheduled. Yet the workload has increased dramatically, as the Reagan administration has doubled the number of approved emergency exemptions to use restricted pesticides since 1980.

Under questioning, Todhunter said over the past two years the agency has issued no new RPARs, or Rebuttable Presumption Against Registration, the action necessary to begin regulating a hazardous chemical. But he said about 16 RPARs from previous administrations have been processed, and new ones may follow this year.

Albert said that there has been a definite change in attitude since the start of the Reagan administration. He cited the pesticide permethrin. "In former years, this agent would have been regulated as a carcinogen," he said. "This is not the case now. My view is that previous administrations tended to be overprotective; the current administration tends to be underprotective."

Albert suggested giving the National Academy of Sciences the job of coordinating the cancer policy for all government agencies and for all substances and across all government agencies.

Todhunter said in a phone interview last night that he thought Albert's comments were "inappropriate." He said Albert has not been directly involved in policy-making and so could not speak authoritatively on it. Albert, he added, "appears to be just coming off the wall on this one."