Two Utah representatives complained to an interim legislative committee Wednesday about plans to dispose of half a million cubic yards of contaminated kiln dust near the city of Magna.

The material, with cadmium, chromium and molybdenum in it, covers about 71 acres. The kiln dust accumulated from 3 to 7 feet deep on a site now owned by Lone Star Industries at 1000 S. Redwood Road, but became deeper when Portland Cement used the site as a dump.Magna residents and the Salt Lake County Commission have voiced opposition to a plan to seal the material at the Salt Lake County landfill near Magna.

The landfill is within Salt Lake City's limits, and city officials have said they would prefer it to be there than remain at the site.

Rep. Daniel H. Tuttle, D-West Valley, told the committee that the site is within three miles of Magna. Although backers of the move say the plastic liner under the dust would be strong, he said area residents worry about eventual leakage.

The underground water supply in part of western Salt Lake County is already contaminated, he said. "Why contaminate it further?"

Rep. Brent Goodfellow, D-West Valley, said two businesses recently moved in not far from the landfill. "We are going to expand to the west," he said.

Moving the waste there could put an end to this growth, he fears.

"I would propose that we aggressively look at alternatives," Goodfellow said.

Kenneth L. Alkema, director of the Utah Division of Environmental Health, told the committee that the site is covered by Superfund legislation passed by Congress. Under Superfund rules, neither a responsible party nor the Superfund account can be used to pay for a more expensive cleanup than the least costly that will protect health and the environment.

In this case, both the state and EPA agree that the least-costly acceptable solution is to cap the kiln dust on site. "It can be done safely," he said.

But the city wants the dust moved, so state officials convinced the EPA that the agency should allow the dust to be shipped to the landfill.

There, special cells designed to last 100 years would be built for the material, Alkema said. They would be lined, capped with clay, and revegetated.

Other projects such as disposing of the waste in the western desert could cost between $30 million and $55 million, with the state or city picking up the difference in the cost over the $13 million.

"There are over 170 of these (Superfund) sites that we are looking at here in Utah," Alkema said. "Over 60 of them are in Salt Lake County right now."

Among these are the Bingham Creek lead pollution, Sharon Steel tailings in Midvale and the Wasatch Chemical pollution, he said.

If all 68 sites in Salt Lake County were moved or had some other treatment that was more expensive than the least-costly safe alternative, the price tag for pollution control could become astronomical.

One possible alternative to moving the Portland Cement dust to the landfill is that U.S. Pollution Control Inc. may accept it as a material to neutralize acids at its hazardous waste disposal facility in Tooele County, Alkema said. "But right now, the costs are still considerably higher than the $13 million" that capping in place or moving to the landfill would require.