WASHINGTON — Thirty-five million workers who drive on the job will have to wear seat belts under a regulation announced Wednesday by Labor Secretary Elizabeth Dole. Even many business people riding in taxis will have to buckle up.

The U.S. Chamber of Commerce said the rule had the potential of being “regulatory overkill.” The AFL-CIO said it didn’t go far enough.

Under the rule, which will take effect after a 120-day comment period and possibly a hearing, employers who fail to make their workers use seat belts could face fines of up to $10,000.

Mrs. Dole told reporters she was unsure when the Occupational Safety and Health Administration will begin enforcing the rule. But she said the process will be expedited with a hearing, if one is requested, to be conducted in January.

She said the new rule could save an estimated 685 lives a year.

The rule will exempt people who are self-employed and businesses with 10 or fewer workers.

Workers riding in taxis enroute to business meetings will have to wear seat belts, even if they are in the back seat, unless the taxi does not have belts. Taxi companies are not required to install back-seat seat belts.

Fred Krebs, manager of the Chamber of Commerce’s business-government policy department, said that it “seems to me that it could be regulatory overkill … that it’s perhaps a little more nit-picking than one would like to see from OSHA.”

Krebs said his initial reaction was that “there might be more significant safety and health issues that OSHA could be addressing.

“Seat belts are a good thing and people should wear them. But whether or not this is a good regulation for OSHA is debatable,” he said.

“There are limits to what employers can do to regulate the conduct of their employees,” Krebs added.

The AFL-CIO, which represents 14.2 million unionized workers, praised the new regulation but said the standard also needs to require vehicle inspection and maintenance.

The seat-belt rule “is a first step in reducing the high toll of job-related motor vehicle fatalities and injuries,” the labor federation said in a statement.