Managers of the Ash Grove Cement Co. plant say a controversy over use of industrial slag to make cement at the Holcim Inc. plant near Three Forks is surprising, because Ash Grove has used slag for 41 years. Slag from the Asarco Inc. smelter at East Helena has been in use since Ash Grove opened its plant less than 10 miles away in 1963, said Joe Scheeler, environmental health and safety manager. Slag from Asarco’s accumulation also went to Holcim.
Last Monday, two environmental groups and some Bozeman-area legislators asked the Schweitzer administration to order that Holcim stop burning slag, because toxins could be released into the air. Holcim has used the slag for almost two years. The Montana Department of Environmental Quality said it has not determined whether a state permit is necessary. Dave Klemp of the agency’s Air Resources Management Bureau said DEQ did not learn of Holcim’s use of slag until March 2004.
If Asarco pays to have the slag transported from the company’s plant, which closed in 2001, then it is considered a hazardous waste. But under state and federal laws, the slag is defined as a "product," with little or no regulatory oversight, if it is purchased for use.
On Thursday, DEQ director Richard Opper said regulators will analyze the slag and study emissions at the Holcim plant. Scheeler said emissions testing at Ash Grove in 2000 found .0092 pounds of metals were released per hour. Holcim tests annually for metals in its emissions, said Heidi Bruner, environmental manager at the plant near Three Forks. The amount of most metals decreased slightly after use of the slag began, she said.
Klemp said it not clear what may have caused the difference. No one can say for sure what is being emitted daily from either the Holcim or the Ash Grove plant, he said. "I could predict the amount of pollutants that could be coming out, but until you actually test the emissions you don’t know," he said. "All I can say right now is this is what we know is coming out. But other things that might be harmful haven’t been tested for, and I think that’s part of what the hubbub is all about. Folks want to know exactly what’s coming out of the stack."