The Reagan administration has decided to review, and possibly relax, the entire list of federal standards limiting worker exposure to poisonous substances, the new administrator of the Occupational Safety and Health Administration said yesterday.

Among standards up for restudy will be those affecting chlorine, asbestos, lead, benezene and coke-oven emissions.

In a radical departure from the past approach in this controversial field of government regulation, Thorne G. Auchter, new head of Osha, announced that his agency will reexamine all existing worker health regulations with an eye to subjecting them to cost-benefit analysis.

This tool, designed to weigh benefits to worker health against costs of compliance, has been advocated in the courts for years by regulated companies as a way of softening OSHA regulations. Its use has been fought just as vigorously by organized labor and other worker organizations.

The administration has already decided definitely to subject one standard to cost-benefit analysis, Auchter said yesterday; the cotton dust standard. By the decision, OSHA may be able to head off a Supreme Court decision on the cost-benefit issue.

Auchter said he would ask the supreme Court not to issue an opinion in a case challenging the current strict standards for cotton dust exposure.

The justices do not have to grant the OSHA request. In the past, however, the court has generally not proceeded in such cases. The cost-benefit question was left unresolved by the court last year in a similar case involving benezene.

Auchter said the agency's success with cost-benefit analysis in the textile industry would help determine whether it will also be applied to other industries. But he made it clear that he already has firm opinions on the subject.

"Cost-benefit analysis is an important tool in producing efficient regulation," he said. "It is a way to make sure we choose the regulatory alternative that offers society the greatest net benefit."

He also said that it was time for OSHA, attacked by businesses as antibusiness, become more "objective" in order to "serve employers and employes equally."

Denuciations of OSHA's action came fast. Ralph Nader, who coined the term "brown lung disease" to describe the respiratory illness caused by cotton dust, said the administration was "knowingly jeopardizing the lives of 75,000 textile workers." The Brown Lung Association in North Carolina called it a major setback to their cause.

The American Textile Manufacturers Association, however, said it "welcomed the proposal."

In a related cotton dust matter yesterday, Auchter said he recalled an agency booklet about cotton dust in part because of its cover displayed a photograph of an aging textile worker who, it was noted inside, died of brown lung disease. An unidentified aide to Auchter tried to prevent his boss from answering questions about the booklet, shouting to reporters from the side of the room that Auchter has already discussed that decision.