Cement plant to limit use of slag.

* Holcim, Inc. has agreed to limit the amount of slag it uses from Asarco's idled East Helena, Mont., plant--and will not use any more slag from a Canadian smelter--after tests from the state showed "a slew" of heavy metals in the slag, according to a report in the Helena Independent (Helena, Mont.).

Holcim, which operates a cement plant near Three Forks, Mont., will voluntarily limit the amount of Asarco slag it uses to 15,000 tons per year, Richard Opper, director of the state Department of Environmental Quality, tells the paper.

"Tests showed arsenic, cadmium, mercury, zinc--a slew of heavy metals--in the slag that could pose a health risk," Opper tells the paper. "We need to know what's coming out of the stacks ... and we definitely will be monitoring their emissions."

The DEQ has determined that 15,000 tons per year meets "negligible risk standards," according to the report.

The Helena Independent reports that in April, Holcim disclosed it had been burning Asarco's slag for about two years, and environmental groups asked the practiced to be stopped because Holcim lacked the necessary air quality permit.