The Reagan administration is moving to curb one of the most hated government agencies in the eyes of American business -- the Occupational Safety and Health Administration. Under consideration are fundamental changes in OSHA policy that ultimately could affect the health of millions of workers.

Hoping to reverse a decade of growing government activism in this area, the White House has ordered a shift of emphasis that it admits will mean less protection for some workers but will help business save money on health and safety regulations.

Specifically, the new policy would:

Require the agency to measure potential worker health risks against the costs to business of forming required health standards.

Give business more options for meeting the standards. This would mean business could require employes to wear protective devices rather than requiring engineering changes in equipment used in the workplace.

Industry for years had advocated the cost-benefit approach to regulations, arguing that it's only reasonable. Labor unions have opposed it just as strongly, arguing that it's inhumane.

The new review standard ordered for a number of Occupational Safety and Health Administration regulations, with and eye to relaxing them, could affect such rules as how much lead, asbestos, cotton dust or benzene will be in the air workers breathe.

"Some workers will be less protected," concedes James C. Miller III, regulatory affairs administrator at the Office of Management and Budget and director of the president's task force on regulatory relief. But he also argues that worker health and protection overall will improve because industry will be better able to allocate its resources to health priorities. "I am absolutely sure of that," Miller says.

Unions, and former OSHA administrator Eula Bingham, violently disagree.

The final decisions will affect millions of workers in hundreds of industries involved in everything from making cotton fabric to turning out steel, from producing gasoline to building ships, and in making paints, plastics and insulation.

At stake is prevention of a variety of major diseases or other health problems, including brown lung (cotton dust), poisoning (lead) and cancer (benzene, asbestos).

Many of the final decisions in molding worker health standards probably will be made not by the Reagan regulators but by the courts, which already have played a central role in such controversies.

In the past, industry often has gone to court to challenge aggressive OSHA regulations. With the new Reagan policy, labor likely will have to take the lead in mounting court challenges.

Thorne Auchter, the new OSHA chief, acknowledges that one of the goals of the new policy is to reduce burdens on business, but he insists that the agency has no preconceived idea of whether the rules will be weakened or strengthened upon review.

Neither business nor labor groups appear to believe this, however.

George Taylor, safety director at the AFL-CIO, says the new policy means that "overall we can't expect any significantly protective standards" from work-related diseases during this administration, contending that cost-benefit analysis is just another way to let employers use the cheapest method of worker protection whether it is effective or not.

Mark A. de Bernardo, a lawyer for the U.S. Chamber of Commerce, on the other hand, said: "We're very encouraged by the [policy changes]. They are steps that go a long way to establishing the credibility of the agency." Like the administration, de Bernardo believes workers will be better protected if employers have more say in determining and preventing health and safety hazards.

Former Osha chief Bingham disagrees. "The trend is to stop protecting workers and let the free marketplace determine safety standards. I thought the country decided 10 years ago [with the act establishing OSHA] that that doesn't work," she lamented.

One of the main problems with making an assessment is the vast difference in estimates on cost and number of workers involved and in trying to quantify the unquantifiable -- the life and health of each affected individual.

What causes byssinosis [brown lung]? The exact agent has not been identified, but it is known that the disease is associated with cotton dust . . . . The horror of this is that workers did not connect the pain in their chests, the coughing, the shortness of breath with the air they breathe on the job. They can't smell what is causing the disease. They can't feel it. They can't see it . . . . The dust that damages the lungs is too small to be seen by the naked eye. Clothing and Textile Workers Union pamphlet

A person going to work in a modern textile plant today, which has a medical surveillance program, will not become disabled with byssinosis . . . . Byssinosis is a respiratory condition attributed to "the action of respirable cotton dust on the respiratory passages of some people." Textile Manufacturers Institute fact sheet.

The cotton dust standard is supposed to be the test case for the Reagan administration's policy change. The Labor Department has asked the Supreme Court to let the new administration reconsider a tight cotton dust standard developed during the Carter years. Organized labor has challenged the request and asked the court to uphold the standard.

In making its decision, the court will find a wide gap in labor and industry's views of the problems and remedies.

The Amalgamated Clothing and Textile Workers Union claims that at least 150,000 of some 800,000 U.S. textile workers suffer from some degree of brown lung and that 35,000 are permanently and totally disabled. The American Textile Manufacturers Institute, representing the industry, puts the estimate at 2,330 workers "who may have a problem."

OSHA under the previous administration estimated the cost of complying with its tighter rules at $625 million in initial capital costs and $84 million a year in opeating costs. The inudstry says complying would cost more than $2 billion in capital costs alone. The textile workers union doesn't have its own cost estimate, but this doesn't stop safety director Eric Frumin from stating flatly that "it doesn't cost too much."

OSHA under the Reagan administration is saying that it is reviewing the cotton-dust standard because a cost-benefit analysis is needed.

But the Carter administration already in 1979 did a cost-benefit analysis of various programs the behest of Congress and then supported a recommendation of a middle-range standard.

Asked why that cost-benefit study wasn't adequate, Auchter said, "That's just it. It was a study, not an analysis," He did not explain what the difference was but said the White House task force would tell his agency how to do it better.

While the Reagan administration is considering relaxing the regulations, a large portion of the textile industry has shown that it can comply with them -- and in fact has found it profitable to do so. For example, the two largest manufacturers, J. P. Stevens and Burlington, now are substantially in compliance -- three years early.

They came into compliance because they modernized their plants, switching to machinery that is both more efficient and cleaner.

But the textile workers union estimates that somewhere around half of all textile workers still are subjected to dangerously high levels of the substance. Some mills, particularly those of smaller manufacturers, don't have the capital to modernize now, and it could be a number of years before they are ready to change to new machines. The question is, should they be forced to spend the money to protect workers in the meantime?

The various sides of the cotton-dust debate agree that in any event it will be a number of years before the issue is sorted out in the courts.

"Industry will go to court or we will," regardless of what standard the Reagan administration comes up with says the AFL-CIO's Taylor.

In the past, the Supreme Court has managed to sidestep the cost-benefit issue, though several times it came close to ruling on it.

In an August 1980 ruling, the Supreme Court struck down a tighter OSHA standard on benzene, a substance used in making paints and plastics but which has been found to cause blood disorders and leukemia. OSHA had contended it didn't need to show that workers would benefit from a stricter rule, much less cost efficiency. The U.S. Court of Appeals had said OSHA had to balance economics against benefits. The Supreme Court didn't rule on that aspect of it, but just said OSHA did have to show a tighter standard would help workers.

Another court case, on rules of coke-oven gases, was expected to lead to a resolution of the cost-benefit debate last year, with the steel industry challenging the Osha's contention that it didn't have to weight costs. In the end, however, the industry abruptly withdrew its challenge, saying that it was mainly in compliance already.

A central element of the cost-benefit debate is how industries can comply with standards once they are written. The administration wants to allow industry more flexibility, including giving them the option to use more "personal protection devices" -- respirators, masks and earplugs, for example -- rather than "engineering controls" -- such as ventilation systems or mufflers.

This could save industries large amounts of money, and the administration says it would result in more effective use of resources. Unions complain, however, that these devices are often ineffective and usually uncomfortable.

But OMB's Miller says the issue is how to provide worker safety in the most efficient way, adding: "It's not the Occupational Safety, Health and Comfort Administration."