Only the Supreme Court could have done it so stylishly.

In its most important toxic substances decision to date, the court recently overturned a new standard developed by OSHA to reduce workers' exposure to benzene, a human carcinogen. The case offers a fascinating view of the interactions of the Supreme Court, Congress and a regulatory agency. And it presents in sharp focus a conflict between the court's duty to carry out the expressed intent of Congress and its duty to decide in favor of sensible public policy.

The decision did what the four dissenters said it did: it took away form the labor movement a political victory it had won when the Occupational Safety and Health Act was enacted in 1970. The statute directed OSHA, when regulating a toxic substance in the work place, to set an exposure standard that would ensure, to the extent feasible, "that no employee will suffer material impairment of health" even if he is exposed to the substance during his entire working life. Strong language. OSHA was trying to carry it out.

But four justices held that OSHA erred by failing to make a specific finding that exposure to benzene under the previous standard presented a "significant risk." The term "significant risk" did not appear in the statute. In a magisterial feat of magic, the plurality found the requirement in a definitional provision.

There is something undeniably odd about that definitional section, however. It defines the term "occupational safety and health standard" as one that is "reasonably necessary or appropriate to provide safe . . . places of employment." The new benzene standard can't be reasonably necessary, the plurality reasoned, unless the current level of benzene permitted is unsafe, and it can't be unsafe unless it presents a significant risk. Ergo, before changing the standards, OSHA must find that benzene at current permitted levels presents a significant risk. OSHA, of course, did not make such a finding because nothing in the statute appeared to require it. Definitions don't ordinarily contain guidelines that modify the substantive provisions of a statute. There is no reason to think Congress intended to set up two different substantive standards (one of feasibility and one of significant risk) in two different provisions of the law.

The plurality noted that "the validity of an agency's determination must be judged on the basis of the agency's stated reasons for making that determination," and it expressly refrained from holding that the record in the benzene case would not support the new standard. Rather, the plurality overturned the new standard because it rejected OSHA's rationale for it, which was based on what the plurality held was an erroneous interpretation of the statute.

OSHA's position was extreme indeed, even though it had support in the words of the statute. OSHA argued that it had a statutory duty to eliminate the cancer risk presented by benzene in the work place, subject to only one constraint: that it not put the regulated industries out of business. That was the position the plurality rejected.

If you disregard the language of the statute, there is much to be said for the plurality's position, and it should not set back the cause of health protection in the work place. Under OSHA's view, an industry had to be forced to the brink of disaster, if necessary, to reduce the perhaps negligible risk from a single toxic substance; the industry would than have few or no resources left to reduce the risk from other toxic substances. Even if OSHA's reading of the statute were correct, it couldn't work over time. Eventually OSHA would have had to alter its course.

The plurality's requirment of a finding of "significant risk" should not present serious problems -- even where data are sketchy. The plurality did not dispute the principle used by all the Health regulartory agencies that any exposure to a carcinogen presents some risk. It merely held that under the Occupational Safety and Health Act only significant risks are to be regulated by standards. Even in the heartland of cancer portection -- the world of the Delaney Clause -- the U.S. Circuit Court of Appeals, in an opinion by the late Judge Harold Leventhal, recently reached an analogous conclusion about an important class of food additives.

The plurality made it clear that OSHA should decide in the first instance what is a "significant" risk and that the criteria for that judgment do not have to be quantitative and do not have to be based on scientific certainty. OSHA can rely on scientifically reputable opinion and conservative assumptions, and need not await evidence of actual human disease. Even the new benzene standard may be sustainable if the record supports a finding of "significant risk" under the plurality's broad view of that concept, an issue the court left open. The court also left for another day the question of whether OSHA must weigh the health benefits from a stndard against the costs of complying with it.

Sometimes a loss is liberating. There is a limit to the amount of resources even our society will devote to protection of health and safety. OSHA has been freed from a policy that over time might have direction it to require vast misallocations of those limited resources. The result may well be more effective health regulation in the work place.

Whether it was appropriate for the court to have distorted the statute as it did is a question that will attract jurisprudential controversy for years to come. It was a bold step even for a Supreme Court.