MISSOULA, Mont.—W.R. Grace & Co. and three of its former executives were acquitted Friday of criminal charges that they concealed the health risks associated with mining asbestos-laced vermiculite in Montana.

Material taken from the mine, which is a Superfund site, is blamed for sickening about 2,000 people in and around the small town of Libby, Mont., and for the deaths of about 225 people.

In 2005, W.R. Grace, which operated the mine from 1963 to 1990, and seven of its former executives and managers were indicted on charges that they conspired to knowingly release a hazardous air pollutant, endangering the lives of mine workers and other local residents. The defendants also were accused of violating the Clean Air Act and with obstruction of justice.

The nearly 11-week trial concluded Friday when a jury unanimously found the Columbia, Md.-based chemical and building materials company and three of its former executives—former Senior Vp Robert J. Bettacchi, former Vp Jack W. Wolter and former Director of Health, Safety and Toxicology Henry A. Eschenbach—not guilty on all charges.

Charges against Robert C. Walsh, a former senior vp of W.R. Grace, and William J. McCaig, a former general manager of operations at the Libby mine, were dropped during the trial earlier this month (BI, May 4).

The other former executive originally indicted has since died.

In a statement, W.R. Grace said it was "gratified" by the verdict. "We always believed that Grace and its former executives had acted properly and that a jury would come to the same conclusion when confronted with the evidence."

A spokeswoman for the U.S. attorney's office in Montana declined comment.

W.R. Grace filed for bankruptcy protection in 2001 in order to address its asbestos-related liabilities. In April 2008, it filed a reorganization plan with the bankruptcy court that called for the establishment of a $3 billion trust to settle all present and future asbestos-related personal injury claims against the company, including those stemming from the Libby mine. W.R. Grace said the plan is a step forward in the company emerging from bankruptcy.