The Environmental Protection Agency's top air-quality official said today that the EPA does not consider the chemical methyl isocyanate to be a hazardous air pollutant despite an accident in India Dec. 3 that killed more than 2,000 persons.

Rep. Henry A. Waxman (D-Calif.), chairman of the House subcommittee on Health and the Environment, called the statement by Joseph A. Cannon, EPA's assistant administrator for air, noise and radiation, "an outrage" and said he will introduce legislation "to force EPA to regulate these hazardous air pollutants."

A hearing was held in an auditorium adjacent to the only chemical plant in the United States where the chemical is manufactured. Leaking methyl isocyanate killed more than 2,000 persons at a plant in Bhopal, India, a sister plant to Union Carbide Corp.'s facility here.

Warren M. Anderson, Union Carbide's chief executive officer, pledged his assistance in drafting tough laws to regulate the highly toxic chemical, which is a key ingredient in the manufacture of several popular pesticides.

Waxman praised Anderson for being "so receptive to learning from the tragedy," contrasted to the EPA's posture, which Waxman called "an absolute disgrace."

Cannon said that while "I wouldn't want to breathe it," methyl isocyanate is not one of 36 chemicals being studied by the EPA for possible inclusion on its list of regulated air pollutants.

Waxman said that was "like we didn't recognize China all those years -- it was still there."

Rep. Gerry E. Sikorski (D-Minn.) ridiculed the EPA's study of potential air pollutants, noting that the EPA has categorized only five of 650 chemicals as hazardous since it began its investigation with the creation of the Clean Air Act 14 years ago.

"At that rate," Sikorski said, "it will take 1,820 years to do something about the remaining chemicals on the list, almost as long as since when Christ walked on Earth."

Waxman asked Cannon, "If 3,000 people died here tomorrow of MIC, would you find it hazardous enough to regulate?"

Cannon, while acknowledging that "the agency from the beginning hasn't done a very good job of implementing" the Clean Air Act, said, "MIC is not a high priority. There is nothing we can do about it."

"What's stopping you?" demanded Waxman.

Cannon said it is not that the EPA or the Reagan administration "lack the will" to attack the problem, and "not because of lobbying by the chemical industry," but because "MIC didn't make the list" of worst pollutants.

Cannon and other administration officials who testified indicated that the lack of action stemmed from confusion in the laws that govern the EPA and the Occupational Safety and Health Administration.

But Sikorski said he detected a "baloney factor" in testimony by Cannon, Jack W. McGraw, the EPA's deputy assistant administrator for solid waste and emergency response, and Jane A. Matheson, OSHA's deputy assistant secretary. Sikorski told the EPA officials "you are proposing more baloney."

While Waxman had praise for Anderson's cooperative attitude, the congressman said he was "disturbed that he Anderson and the plant manager didn't know much about the constant exposure of MIC to the community.

Anderson maintained that the plant was sealed, although a report compiled by Union Carbide for the West Virginia Air Pollution Control Commission showed that the chemical and other deadly poisons regularly seep into the air here. The extent of those leaks is not clear.

Until a few days ago, the state commission was relying on a 1981 filing by Union Carbide that reported that the 1,400-employe plant emitted 11.74 pounds of methyl isocyanate an hour. When the subcommittee staff asked to see the records a few days ago, Union Carbide sent in a revised figure of .62 pounds an hour, saying that it had earlier miscalculated.

Waxman said he was worried about the damage that 12 pounds of the chemical in the air might do when "a couple drops can drive everyone out of an auditorium" the size of the one at West Virginia State College that was the site of today's five-hour hearing.

"I don't consider these to be small discrepancies," Waxman said. "EPA doesn't know how much methyl isocyanate is escaping ; the state doesn't know, you'd expect Carbide to know."

Rep. Robert E. Wise Jr. (D-W.Va.), whose district includes Institute and most of the region's chemical plants, won a pledge from the federal officials here to press the State Department to ask Indian officials to allow teams from EPA and OSHA to visit the Bhopal plant "before it's all cleaned up." The request was first made last week by Gov. John D. Rockefeller IV and the state's congressional delegation.

Rep. James J. Florio (D-N.J.), chairman of the Energy and Commerce subcommittee on commerce, transportation and tourism, said he was troubled by EPA's "circular approach, which never allows for a solution to problems."