The Occupational Safety and Health Administration has decided against adopting a regulation to protect workers from brief, high-level exposures to ethylene oxide, a cancer-causing chemical commonly used to sterilize medical equipment.

In June, OSHA announced a new, tougher standard for ethylene oxide that restricted the colorless, odorless gas to no more than one part per million in the air, averaged over an eight-hour work day. But OSHA put off deciding whether the standard should include a short-term exposure limit.

Labor unions and health groups contended that the new standard was toothless without a short-term limit, because workers could continue to be legally exposed to high levels of ethylene oxide for brief periods.

Under normal circumstances, workers are exposed to ethylene oxide only intermittently, when they open and unload sterilizing chambers. But research has shown a threefold increase in miscarriages in hospital workers exposed to ethylene oxide for as little as 10 to 20 minutes per day.

Industry officials, however, argued that no short-term exposure limit was necessary. OSHA chief Robert A. Rowland agreed, saying a STEL is "not warranted by the available health evidence" and "not necessary or appropriate for inclusion" in the final standard.