Lake Forest, Illinois, USA, 29 July 2008 -- (BUSINESS WIRE) -- Packaging Corporation of America (NYSE: PKG) reports that on 29 July, 2008, at approximately 1:30 p.m. Central Time, an explosion occurred in a recycled fiber storage tank at its Tomahawk, Wisconsin, paper mill, which resulted in three fatalities. The three individuals were employees who were engaged in maintenance activities on top of the tank when the explosion occurred. A fourth employee, who was standing on a platform at a lower level of the tank was injured. The exact cause of the explosion is not known and is under investigation.

Names of the deceased and injured employees have not been released pending notification to their families.

Further information will be released, as appropriate, when it becomes available.