Industrial elation and regulatory panic over the U.S. Supreme Court demolition of benzene exposure limits seemed to subside yesterday into general agreement that there was less to the verdict than at first met the eye.

Instead of having vast ramifications for all regulations that govern toxic substances of any kind, as was first thought, the unusually split vote appeared on close reading to deal rather specifically with particular actions taken or not taken in a particular case, according to attorneys for all sides.

The high court ruled 5 to 4 Wednesday that the Occupational Safety and Health Administration (OSHA) had exceeded its authority in reducing the amount of cancer-causing benzene tolerable in the air of a job site from 10 parts per million to one part.

The agency had not shown, Justice John P. Stevens wrote for himself and three other judges, that the higher benzene level "presents a significant risk of material health impairment" for workers. Neither had OSHA shown "substantial evidence" that the lower level would present any appreciable benefits.

All over town, high-priced lawyers pondered whether OSHA's failures had been repeated in setting scores of other standards for other toxic substances in the air, the water and the workplace. The general agreement, cautiously stated, was: probably not.

"I don't think it will affect our operations very significantly," said Michelle Korash, general counsel for the Environmental Protection Agency. "What the court requires is entirely consistent with the way we have approached regulatory decisions."

OSHA had argued that because benzene undeniably is a carcinogen, and because there is no level below which a carcinogen can be called absolutely harmless, the exposure standard should be set as close to zero as possible without driving the company involved into bankruptcy.

Stevens' opinion said that "substantial evidence" still had to be produced for setting a standard at a particular level. While OSHA's evidence in support of a limit of 10 parts per million was "sketchy at best," he wrote, it would suffice, since the court was not trying to lock OSHA into "a mathematical straitjacket" and the agency still had total responsibility for deciding which levels of risk were "significant" and which were not.

But OSHA, he argued, had produced no evidence to back its reduction of the standard from 10 parts to one part. Simple declaration that the substance is a carcinogen is not enough, Stevens wrote.

"We don't ban a pesticide because if you took the bottle and drank it you would drop dead," said Korash of EPA. "We look at the risk posed when it is diluted and sprayed and the person is standing under the airplane. . . . As I understand it there was no effort to do that in this [Osha] case."

Other attorneys agreed the verdict seemed to say that any evidence whatsoever in favor of a reduction in the standard would have been acceptable in the court's eyes.

"It might have been a very different verdict if OSHA, in an abundance of caution, had even addressed the need," said William Butler, president of the Environmental Defense Fund.

"It does mean that agencies are going to have to present evidence beyond what they've done in the past to support proposed reductions in a given standard," he continued, "and the quality of that evidence is likely to be very sketchy because it's entirely extraapolation" from studies involving high does to animals.

"It would seem to require a greater degree of certainty than a lot of us are willing to say is there, but the court did not suggest that sketchy quality was insufficent,' Butler said.

The EPA's Steven D. Jellinek, administrator for pesticides and toxic substances, agreed that the court had left things open for OSHA to try to make a case for the tougher benzene standard.

"Future litigation will be over whether an agency has made a case for significant damage at particular levels" of exposure to the substance at issue, Jellinek said. "My concern is the difficulty of demonstrating significant harm and actual effects at very low levels of exposure.

"I do think it will make it harder for us to take action where we don't have high exposure levels. Not impossible, just more difficult."

Threats to existing standards are ruled out for the most part because the 60- or 90-day challenge periods set by law have expired, most attorneys noted. A cumbersome petition for review could be initiated in some cases, but the ruling will chiefly be felt in new standard-setting procedures.

At OSHA, officials said, in effect that it was back to the drawing board on benzene. New standards for other substances also might be delayed, they said.