The DOE demolished a number of structures -- including some from the World War II-era --at the Hanford site in 2009 and 2010 as part of the cleanup effort.

According to the EPA, the removal and management of materials containing asbestos was potentially threatening to workers' health and safety.

Many of the old buildings have asbestos in the insulation. The EPA says the violations were discovered during an evaluation in 2012.

In March 2013 the department and subcontractors agreed to limit the use of heavy demolition equipment on buildings that could potentially contain asbestos out of concern for the health of workers.

EPA says using large heavy equipment to tear down the buildings could potentially spread dust containing the toxic chemical.