Is it waste or not?

Is it waste or not?
06 April 2005

In Montana, Asarco’s extensive slag pile is regarded as a "toxic substance" while it’s on the property of the East Helena smelter, but the exact same material is transformed into a "feed product" with little or no state or federal oversight when used to make cement at the Ash Grove or Holcim plants. The transition from toxic substance to valuable product basically comes about because Asarco is being paid for the slag, according to state officials, and federal laws promote this type of recycling.

"Technically, the slag is a byproduct on a mining or smelter site," said Rick Thompson, solid waste section supervisor for the Department of Environmental Quality. "We have been told by our folks that Holcim is purchasing the material, and if they’re purchasing it as feed stock for its iron content, then it’s not a waste product." And if it’s not a waste product, neither the federal Environmental Protection Agency nor the state DEQ tracks its disbursement. However, if Asarco were paying Holcim or Ash Grove to remove the slag from the East Helena smelter, it could be considered a waste product.

"It just depends on how the money flows," Thompson said. "It’s a waste if Asarco is paying Holcim to come get it, but it’s a product if Holcim is paying Asarco for it." The question of whether the slag is a toxic substance or just an inert glass-type of smelting byproduct has long been debated. Asarco officials contend that when properly handled, the slag doesn’t pose any threat to the environment. Still, the company was required to report the slag to the federal government, which included it as a toxic substance on its annual "Toxic Release Inventory." Every year, for almost a decade, Asarco topped Montana’s list of toxic substances because of the slag pile.

The debate over the slag’s makeup came to the forefront this week after an environmental group learned that Holcim, located near Three Forks, and Ash Grove near Montana City have been using Asarco’s iron-rich slag to make cement. While Holcim only has been using it for the past few years, Ash Grove apparently has included the slag in its process for around three decades.

Although the slag itself isn’t burned, concerns were raised Monday that when baked, it could release a range of toxic chemicals, including lead, arsenic and cadmium. The environmental groups want the state to stop the cement plants from using the slag until they learn what’s winding up in the air from cooking the slag. Others note that toxic wastes typically are encapsulated in cement to keep them from leaching into the environment, and note that this "recycling" means that less ore has to be mined. Regardless of the slag’s use, it became clear Tuesday that no one is keeping track of where it’s going.

The East Helena smelter, which shut down in 2001, is a Superfund site whose cleanup activities are being orchestrated under the oversight of the federal Environmental Protection Agency. But due to the many other more pressing environmental issues surrounding the site - like an underground arsenic plume and high lead levels in neighborhood soils - monitoring the slag pile wasn’t near the top of the EPA’s to-do list.

"From our perspective, we decided that since it was just sitting there, not going anywhere - like blowing in the wind - we took a look at it but decided that nothing had to be done with it," said John Wardell, Montana’s EPA director. (Abstracted from

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