Filed by attorney Michael Kelley, of the firm of Kelley & Ferraro, on behalf of several unions whose workers were involved in asbestos-related industries, the suit specifically seeks to block the retroactive provisions of the asbestos law.

According to the plaintiffs, when the law becomes effective Sept. 2 it would change the rules governing asbestos-related lawsuits already in the courts and make it more difficult for those who haven't filed claims prior to that date but have already been exposed to asbestos.

"In particular peril are the rights of plaintiffs who brought tort actions arising from their asbestos exposure before the effective date of the bill," the complaint said. "These plaintiffs unquestionably had viable claims under the law as it stood when they filed their actions, but the legislature has now sought suddenly to deprive them of their rights, literally in the midstream of their litigation."

Supporters of the law said that it has wide support in the state, and those who are truly sick would not be deprived of their rights.

"The new law establishes medical standards, consistent with the American Medical Association guidelines, for proceeding with asbestos lawsuits," said David Hansen, chair of the Ohio Alliance for Civil Justice, a coalition of organizations including several major business groups in the state.

"We believe Ohioans support this new law because it is fair and helps those who are truly ill now, while still allowing those who may get sick in the future to file lawsuits. The new law was passed following a lengthy legislative process in which all sides were heard," said Mr. Hansen.

He said the Alliance had been prepared to run a "vigorous, bipartisan," campaign if the referendum had taken place, with support from physicians, labor, businesses, government leaders and others. Had the referendum been filed and enough signatures gathered by Sept. 2, the law would have been blocked until the vote took place.

The new law, Mr. Hansen argued, is necessary to ease the strain on the state's court system. "People who are truly sick from exposure to asbestos currently cannot get fair and timely compensation because Ohio courts are clogged with thousands of asbestos cases, most of them filed by people who are not sick," he said.

According to Mr. Hansen, Cayuga County is one of the five most congested asbestos dockets in the nation with over 41,000 cases pending. Additionally, he said, seven companies in Ohio have declared bankruptcy due to asbestos litigation, and at least 150 companies with at least 150,000 employees in the state are currently facing asbestos claims.