asbestos chrysotile fibers that cause lung disease, COPD, lung cancer, mesothelioma

The University of Montana's McGill Hall is still closed after being shuttered in early February because of an unacceptable amount of asbestos, according to an article on the MNBC Montana website.

On Feb. 7 the hygienist UM hired to help with cleanup said it would be quick, and classes would be able to restart in McGill by Feb. 14, but that estimate has proved to be optimistic.

The building was tested in 2011 for asbestos, and the results came back clean. It's unclear how the situation changed, according to the article.

Students taking courses in the building are frustrated as some classes have been canceled for two weeks while facilities staff assess and address the situation.

Asbestos is strong, yet flexible, and is known for its ability to resist flame and heat. At the end of World War II and for the next 30 years, asbestos was used extensively for school construction and renovation, as well as in floor, ceiling and wall materials in commercial settings.

Now, asbestos is found in as many as 3,000 commercial products in concentrations ranging from 1 percent to 100 percent, according to the EPA. Some of those products include vinyl floor tile and adhesives, insulation, textured paints, coatings, ceiling tiles, HVAC duct insulation, roofing shingles and felt, and even chalkboards.

Asbestos exposure has been linked to serious and often fatal health problems. Diseases such as asbestosis (a non-cancerous respiratory disease), and mesothelioma (a rare form of cancer), have been directly linked to asbestos exposure.