The Labor Department announced tough new rules yesterday to protect American workers from lead poisoning. The lead industry immediately attacked the regulations as inflationary and challenged them in court.

The new standard - one of the most far-reaching yet imposed by the department's Occupational Safety and Health Administration - would reduce permissible exposure levels to one-quarter the present limit over a 10-year period.

OSHA officials said "very speculative" estimates indicate the regulations could cost up to $300 million a year in capital and operating costs - for a total of $3 billion - over the 10-year phase-in period. However, THey said these costs would be at least partially offset by health cost savings.

OSHA has estimated that 835,000 workers in smelting, battery manufacture, shipbuilding, automaking, printing, paint and construction industries are currently exposed to lead a highly toxic substance that attacks the central nervous system, brian, kidneys and reproductive organs and can be fatal.

About 100,000 of these workers are exposed to airborne lead levels in excess of what OSHA has proposed as a limit, according to the agency,

"The dangers of lead have been known for many years and recent scientific studies show that these hazards are more severe than previously thought," said OSHA administrator Eula Bingham. "Worker protection is long overdue."

The new standard, which will take effect Feb 1 unless overturned by the courts, would lower the permissible exposure level from 200 to 50 micrograms per cubic meter of air, averaged over eight hours.

IT also mandates "medical removal protection" that would require employers to transfer - without loss of pay or benefits - any worker whose level of lead in the blood exceeds certain limits to be phased in gradually.

Industries would have up to three years to bring airborne lead levels to 100 micrograms and from 5 to 10 years to reduce them to 50 micrograms. In the meantime, protective devices such as respirators would have to be used.

The 50-microgram limit is considerably tighter than a 100-microgram limit that OSHA initially proposed several years ago, although OSHA officials said it would not be all that much more expensive to implement.

The earlier proposal was attacked last year by the government's Council on Wage and Price Stability as too costly to industry. But yesterday both CWPS and the president's Council of Economic Advisers said they would not protest further.

"This obviously is a very costly regulation, and that is always a matter for some concern," said a CEA spokesman with concurrence from CWPS. "CEA did review this regulation and found no major problems to warrant further activities on our part." The spokesman noted with approval that separate compliance schedules were set for different industries, saying this would enhance "cost-effectiveness in regulations."

Earlier this year, OSHA and the White House inflation fighters squared off over a cotton dust standard, with President Carter ultimately imposing a compromise. Later he pledged government would fight inflation by cutting costs of regulations.

Bingham yesterday described the lead standard as "consistent with the commitment of this administration to move aggressively against serious health hazards but to do so in a least-cost manner."

The Lead Industries Association, representing major lead producers and users, disagreed, charging that the standard violates Carter's anti-inflationary goals as the group filed suit to block the standard in the 5th U.S. Circuit Court of Appeals in New Orleans. That court recently overturned OSHA's benzene standard on cost-benefit grounds, setting a precedent that could be fatal to many OSHA proposals. The government has said it will appear.

It was not clear, however, whether the legal battle over the lead standard would be fought out in the 5th Circuit. In what has come to be called the "race to the courthouse," the United Steelworkers of America arrived at or about the same time at the 3rd Circuit Clerk's office in Philadelphia with a challenge to the standard - a preemptive legal strike aimed at getting the case heard in a friendlier court. Unions generally applauded the lead standard. The Punlic Citizens Health Research Group, affiliated with Ralph Nader, praised most of the standard's provisions but said the gradual phase-in of the medical removal protections would leave workers exposed for too long to high lead levels.