Just when Midvale residents thought officials had a handle on cleaning up Sharon Steel's toxic smelter tailings, along come state and federal health experts with the news that another environmental threat must be rectified.

Environmental Protection Agency and state officials briefed Midvale residents Thursday about health and environmental hazards of the Midvale Slag Site, which is north of 7200 South between 700 West and the Jordan River. The much-publicized Sharon Steel tailings site is south of 7200 South.Kenneth Alkema, director of the Utah Environmental Health Department, told the Deseret News that slag was left after ore was smelted; the lighter tailings were created when the ore was ground.

The slag site has contributed to groundwater contamination. In addition, heaps of slag material are still piled on the site of the defunct U.S. Smelting, Refining and Mining Co. smelter, where hazardous material could blow away in high winds.

Studies conducted by the EPA and the state show that soils and slag on the slag site contain high concentrations of lead and arsenic, which could be a threat if there were long-term exposure.

How serious a problem it is will be determined when the EPA completes its latest sampling of soil and slag on the old Sharon Steel site.

EPA officials announced Thursday additional sampling will begin later this month and should be completed by July.

To save time, the northern portion of the site - where the waste isn't as visible - will be studied first.

"The cities want to build a road across part of the site, so we decided we would segregate that part out and study it first," said Eva Hoffman, EPA project manager. The proposed road will extend 7200 South across the Jordan River from Midvale to West Jordan.A federal judge has approved a $60 million cleanup of Sharon Steel's dusty tailings, which have blown into yards. The site of the former smelter is owned by Mining Remedial Recovery Co., but three other companies are paying for the cleanup.

Hoffman, who issued handouts to residents about lead and arsenic exposure, said the EPA has two primary concerns about the slag site.

"We are interested in any kind of contamination that may have hit the soils that people are exposed to from the smelter fallout," she said."The smelter operated around 90 years. Particularly in the early days when there wasn't much in the way of air controls, the smelter emitted loads of dust."

When experts took samples more than a year ago from residents' lawns, looking for tailings, they uncovered any problems in those areas that might be tied to the slag as well, said Alkema.

"There's nothing new off-site that's been identified," he said. What is new is the discovery of groundwater contamination, which is a threat to the state's natural resources, and the identification of hazardous material piled up on the site.

At the site, workers regularly haul away some of the hard, black material so it can be used for grit and sandblasting. The danger is that material could blow from the site, he said.

The EPA will also take samples from the sewage lagoon to determine if the sludge contains hazardous waste.

"Then we will get our analysis back, we will be able to tell the town whether they've got big problems in building that road, or little problems, or no problems. If we find problems in the path of the road, it could be that the road could be shifted a bit to avoid them," Hoffman said.

The EPA wants to ensure their cleanup efforts and the road design are compatible.

"I think it would be a horrible thing for the federal government to fund a road to go through a site and then another federal agency goes in and tears it up. That would be a disaster," Hoffman said. "So for once all the government agencies are working together."