BALTIMORE, MAY 24 -- Maryland Gov. William Donald Schaefer said today he will veto the most heavily lobbied bill passed by the General Assembly this year, a measure designed to clear the way for hundreds of millions of dollars in asbestos-related lawsuits.

Schaefer complained that there was no "finality" in the measure, which would have eliminated the current 20-year limit on bringing suits against building material manufacturers and suppliers.

The bill had been proposed and actively supported by labor unions and lawyers, and opposed by the state's business establishment.

During a news conference at the state office building here, Schaefer called his decision "tough." Thousands of lawsuits have been filed by people who claim to have gotten lung diseases as a result of exposure to asbestos decades ago.

But the governor said his veto was made easier by circuit court decisions in Baltimore and Baltimore County this month holding that personal injury suits could proceed despite the 20-year limit, called the statute of repose.

The veto likely will make it more difficult, however, for school boards across Maryland and the state government to win lawsuits against manufacturers and suppliers when they seek to recover the estimated $200 million cost of removing asbestos from older buildings in the state.

It is possible, Schaefer said, that the administration will support legislation next year to deal with property damage claims, which were not addressed in the circuit court decisions.

Schaefer said he could not sign the bill because it was so open-ended, adding that it would be even more unfair to apply such a law retroactively. "You've got to have finality somewhere in the law," Schaefer said.

Because members' terms expire this year, the General Assembly will not have a chance to override the veto. The governor's office has been flooded with mail on the measure since the legislature adjourned April 9. Business interests, including Schaefer's chief political fund-raiser, lawyer Robert S. Hillman, wrote urging a veto. Letters from school boards and labor unions pleaded that the measure be signed.

Charles Krautler, senior vice president of the Maryland Chamber of Commerce, said the measure would have been bad for the state's business climate, adding that the recent court decisions have accomplished part of the bill's intent.

However, Edward A. Mohler, president of the Maryland State and D.C. AFL-CIO, said he was disappointed by the veto of what he called "a prime piece of labor legislation." The circuit court decisions could be overturned by appeals courts, he said, leaving thousands of injured construction workers with limited legal recourse.

Susan R. Buswell, executive director of the Maryland Association of Boards of Education, said the veto will make it more difficult for schools to sue to recover millions of dollars for asbestos removal required by federal law.

Also today, Schaefer said he plans to veto 15 other bills on policy grounds.

Among them is a bill that would have prohibited Baltimore County from levying a tax on beverage containers and a measure distributing $12.5 million in special funds to the City of Baltimore and three counties.