BILLINGS — Test results from huge piles of wood chips that were being sold from a Montana Superfund site for use in landscaping show they contain some asbestos, but at levels so low federal officials said they posed no danger to humans.

The results obtained Friday by The Associated Press appear to offer a rare bit of relief for the town of Libby, where widespread asbestos contamination has killed an estimated 400 people and sickened 1,750.

The testing followed concerns raised by local officials, residents and business owners who bought loads of the material to spread around their homes, in parks and for use as erosion control. Prior tests indicated the presence of asbestos in the piles, but not how much.

Thousands of tons of the wood chips were shipped out of the Libby area for retail sales across the country. The sales went on for years before federal regulators stepped in last year to halt the practice.

The Environmental Protection Agency found no asbestos in recent air tests designed to mimic human exposure from spreading the wood chips. The agency previously had said a “very low level” of asbestos had been found in tests of the wood chips themselves.

“It was all good news,” said Rebecca Thomas of the EPA’s regional headquarters in Denver. “There simply is no measured exposure.”

No further EPA actions were planned on the wood chips, Thomas said.

But one city official said he was still wary of the wood chips despite the results.

It remained uncertain whether sales will resume. The head of the local economic development agency that had sold the material said no decision had been made, citing lingering uncertainties over the dangers posed by Libby’s asbestos.

The EPA has yet to complete its risk assessment for the town, considered the deadliest Superfund site in the nation. Libby was contaminated by decades of vermiculite mining by W.R. Grace Co., which released countless asbestos fibers that blanketed Libby and surrounding forests.

Initial results from the pending study on the toxicity of the fibers determined even minute amounts can cause non-cancerous illnesses. Thomas said the small amount of asbestos found in the wood chips was below levels considered potentially harmful.

Paul Rumelhart, executive director of The Kootenai River Development Co. said that if the sale of the chips resume, the agency might require a permit so officials could track the material.

Kootenai River controls the shuttered Stimson timber mill that contains the sprawling, open-air piles of wood chips.

“We might not allow it to be taken until the final results are out on the tox study,” Rumelhart said.

But Libby councilman and landscaping business owner Allen Olsen said he won’t use the wood chips regardless of the EPA’s the results.

Olsen used the material by the truckload in the past. He said he has developed a mistrust of the EPA in the decade that the agency has overseen the cleanup in Libby. That effort has cost more than $370 million to date and is years from completion.

“I absolutely, positively will not sell it or let a person have any of it,” Olsen said. “There’s just been too many controversies.”

U.S. Sen. Max Baucus, a longtime advocate for Libby in Congress, said the EPA test results were important for the town.

“It’s critical the EPA continues doing everything necessary to make sure folks in Libby get the attention and transparency they deserve,” he said.

The AP reported last July that more than 15,000 tons of the chips and bark were sold or distributed and much of that material shipped across the country, despite evidence it contained an unknown level of asbestos.

Samples from the timber mill piles were first collected in 2007, and subsequent tests found asbestos in four of 20 samples analyzed under an electron microscope. The EPA at the time did not attempt to quantify how much asbestos was present.

The agency also has been criticized for wetting down the piles prior to collecting the samples, which could have made it harder to detect fibers. The samples recently analyzed were collected in August when conditions were hot and dry, Thomas said.