Asbestos has been found in isolated areas of the Ash Grove Cement limestone quarry in Montana City, according to tests done by the federal Mine Safety and Health Administration.

Responding to an e-mail request for test results by the Independent Record, an MSHA spokeswoman confirmed Wednesday that several samples taken from the quarry last month contained tremolite asbestos.

"MSHA's bulk sampling results indicate that tremolite asbestos is present in the pit as isolated occurrences due to geologic intrusions into certain zones of the quarry," Amy Louviere wrote. She added that "analysis of the majority of the bulk samples resulted in 'non-detectable' findings."

A company spokeswoman declined to elaborate on the positive asbestos tests, saying Ash Grove would wait until all test results are known before developing a plan of action with state and federal agencies.

"It is inappropriate for us to comment on MSHA's data at this time," Jacqueline Clark said in an e-mail response to the Independent Record. "This is mainly because our bulk samples are still undergoing analysis, so it is premature for us to determine what mining approach we will take in the quarry and how we will operate the plant until we review all the results and confer with the government agencies."

Results of dozens of tests in and around the quarry and plant are still outstanding, including tests done by both the company and the Montana Department of Environmental Quality.

So far, the company has reported finding no asbestos in tests of its finished cement product, in dozens of air samples taken at both the quarry and plant (when neither were in operation) and in wipe samples taken from the plant and quarry designed to capture dust.

Travis Smith, a control room operator and head of the union that represents 57 hourly workers at the plant, said after a union meeting Wednesday afternoon that his members aren't too concerned about the positive tests and are eager to return to their jobs.

"We don't see anything from a health standpoint in the past that really scares us for the future," he said. "The level of confidence in the way things are being handled by the state and by the company is high. We're all concerned about the tough economic times. Everybody wants to do what's right for the community, but we want to get back to work."

The plant has been closed since March 16 while federal, state and company officials worked to determine the nature of the mineral tremolite found in February in one area of the quarry. Ash Grove paid its employees to stay home for two weeks, and is picking up the hourly workers' insurance premiums through April.

In one of its naturally occurring forms, tremolite is a form of asbestos that when inhaled can be harmful to human health. Inhaled asbestos fibers pierce the walls of the lungs and cannot be removed, possibly leading to asbestosis or mesothelioma, a form of lung cancer.

Tremolite asbestos was associated with the vermiculite mined in Libby.

In a meeting of state and federal officials earlier this week at the Capitol, Jane Smilie, administrator of the health department's Public Health and Safety Division, said historical medical records don't show anything unusual that could be related to asbestos in the Montana City area.

In checking the Montana Central Tumor Registry for the years 1983 to 2007, Smilie found no data for lung cancer or mesothelioma in Jefferson and Lewis and Clark counties that was at odds with state or national rates.

She added that voluntary hospital discharge data from 2000 to 2006 showed no asbestos-related primary hospitalizations in either county.

DEQ Director Richard Opper said the agency will await its own test results, which he expects to have in hand late this week or early next, before a plan of action is developed.

"I think it's safe to say we're not looking at anything that would compare in intensity to (Libby), but we don't know until we get our results back," he said. "There's no cause for panic. I don't think we're going to get results that show long-term, serious exposure on the part of the workers or the community, but again we don't know that yet."

In her e-mail, MHSA's Louviere said the presence of tremolite asbestos would call for "selective mining," in which portions of the quarry would be left alone.

"Ash Grove officials indicated that areas where tremolite asbestos was found will not be mined and those two areas will be barricaded and appropriate warning signs posted," she wrote.

John Harrington: 447-4080 or john.harrington@helenair.com.