"For years, the wastes from burning coal and producing copper have enjoyed a second life, used in sand-blasting to remove paint, rust and grime from ship's hulls, storage tanks, bridge trusses and other surfaces. Painting contractors, shipyard workers and thousands of others in Baltimore and across the country are said to use the black, gritty material called slag. Now, though, questions have been raised about whether those who do blasting with ground-up coal or copper slag may be unwittingly exposing themselves to toxic contaminants that could damage their health."
"The Occupational Safety and Health Administration says coal and copper slag contain traces of highly toxic beryllium, arsenic and other contaminants. Federal regulators are investigating whether manufacturers of the blasting grit have provided adequate notice that users could be inhaling potentially harmful substances."
Timothy B. Wheeler reports for the Baltimore Sun February 26, 2012.