EPA report: Asbestos levels declining at Libby schools

The Environmental Protection Agency announced during a public meeting on Monday that asbestos levels in and around Libby schools are much lower than in years past and do not pose a risk to children.

“The first, probably most important question is, is it OK to send my children to school here in Libby, and I think the answer is yes,” said EPA Toxicologist David Berry. “Levels that were detected in the activity-based sampling were within acceptable exposure levels as evidence and used at other Superfund sites in the United States.”

The scientific methods of measuring the amount of asbestos fibers in the air and soil and the means by which a toxicity value was assigned to Libby amphibole, the area’s unique form of asbestos fiber, left some attendees uncertain.

“Is that apples to apples?” asked Duane Williams. “Do those other sites contain Libby amphibole or tremolite?”

Because EPA’s toxicity studies concerning Libby amphibole have not been completed, the EPA uses the toxicity value of a different asbestos fiber when determining risk. Some believe that Libby amphibole is the most potent type of asbestos.

“There aren’t hard numbers,” Berry said. “The numbers we are using are based on the (toxicity value) for chrysotile tremolite, so they don’t specifically address Libby amphibole but they give us an idea of what the theoretical risks would be for Libby amphibole.”

Berry didn’t address Williams’s question as to how the EPA determined that the two different asbestos fibers had similar toxicity.

Attendee Gordon Sullivan asked, considering the EPA’s current method of measuring asbestos fibers, if a “non-detect” sample demonstrates an absence of fibers.

“No,” Berry replied, “but it’s the best method we have for detecting Libby amphibole in the soil at this time.”

Sullivan pointed out that a non-detect reading could still, in his opinion, be dangerous.

The EPA took air and soil samples last year at five Libby school campuses including the administration building, high school, middle school, Asa Wood and the former Plummer building that now houses Head Start.

Two-day composite samples recorded the indoor air quality in various areas of all of the buildings. Out of 51 samples, 49 did not detect the presence of asbestos. One detection occurred in a Libby Middle School hallway and another in an Asa Wood classroom.

Berry pointed out that the fibers were most-likely brought into the schools on shoes or clothing.

EPA detected asbestos in five out of 63 outdoor activity-based samples, which were taken while simulating student and maintenance worker activities such as swinging, playing sports, mowing lawns and sweeping. The five samples were just barely detectable using EPA’s current method, Berry said.

Out of the 41 soil samples taken outside the schools, 31 revealed a trace amount of asbestos, which is defined as detectable but less than 0.2 percent. All buildings except the middle school had at least one example of visible vermiculite.

Soil samples in 2001, Berry said, revealed asbestos levels as high as 15 percent at the middle school, due mostly to the track made of mine tailings, and 8 percent at the high school. Soil sampling in 2001 also showed no asbestos outside the administration building, though last year’s testing revealed trace amounts.

“I think the reason why we’re seeing trace here is because we have better sampling as we move to 30-point composite sampling in soil,” Berry said.

Libby will always have a certain amount of asbestos, Berry said, but the testing in schools shows improvement.

“The outdoor levels have been significantly reduced. The air quality has significantly improved,” Berry said. “Libby amphibole will remain at low levels in the Libby valley for probably a long time. We can expect to see sporadic detections of Libby amphibole in indoors and outdoor areas.”