The top guns of business and labor fired statistics like bullets yesterday in an increasingly hostile battle over the future of the Occupational Safety and Health Administration.

There were no facilities. However, both sides reported injuries to what they consider their version of the truth.

The scene of the shootout was Room 1232 of the Dirksen Senate Office Building, where the Senate Labor and Human Resources Committee has been conducting hearings on a bill that could greatly restrict OSHA's powers to conduct on-site plant safety inspections.

The numbers came first from Labor Secretary Ray Marshall who claimed that, between 1973 and 1978, OSHA helped to bring about a 13 percent reduction in the national workers' injury rate (the annual number of injuries per 100 workers).

"This means that there were almost 4 million fewer injuries between 1973 and 1978 than would have occurred at the 1973 rate," Marshall said. He added that, in the same period, firms with 11 or more employees experienced a 14 percent reduction in worker fatalities.

Dr. Richard L. Lesher, president of the U.S. Chamber of Commerce -- "the largest federation of business and professional organizations in the United States" -- fired back.

"The fact is that since 1971, serious injury and illness rates have increased dramatically both in number and in severity," Lesher said.

He contended that OSHA, in its 10 troubled years of existence, "has failed to reduce serious injuries in the workplace" and has contributed to their increase by "diverting limited government and private sector resources to counterproductive ends."

In attempting to support his argument, Lesher cited Department of Labor lost workday figures (days lost through work-related injuries and illnesses) from 1972 through 1978.

According to the Chamber's assessment, the number of lost workdays increased 33 percent in the six-year period, Lesher said.

Eula Bingham, assistant secretary of Labor for occupational safety and health, said Lesher's shot hit the wrong target.

Under OSHA regulations, injured workers have the right to receive pay during convalescence, she said.

"That means they are more likely to stay home and recover from an injury than they would if they were not receiving pay," she said.

The implication was obvious: before OSHA, more workers went to work injured.

AFL-CIO President Lane Kirkland and Howard D. Samuel, president of the federation's Industrial Union Department, also contributed to the statistical battle.

"For the first seven years of its history, OSHA was not given a chance," Kirkland said. He said the agency "was picked out by right wing groups and business associations as a symbol of big government's interference with laissez-faire business practices.

The critics overlooked "the fact" that work-place fatalities "have decreased 10 percent during the program's history" and that there has been a "15 percent overall decline in workplace injuries" since OSHA's inception, Kirkland said.