A long-awaited federal report on Monday revealed that asbestos air concentrations in Libby today are about 100,000 times lower than when the W.R. Grace & Co. vermiculite mine and processing facilities were in operation.

The mine operated from 1963 to 1990.

The air quality in Libby is similar to other Montana cities, due largely to the cleanup efforts of the U.S. Environmental Protection Agency, according to Deborah McKean, the EPA’s lead toxicologist for the toxicology review of Libby amphibole asbestos.

“The cleanups we’ve engaged in are indeed protective,” she said. “Libby is a good place to live and visit.”

The EPA released two official documents on Monday: A toxicological review of Libby asbestos that is final and not subject to further review; and an Integrated Risk Information System health assessment that is now open to public review for the next several months.

Public meetings are planned in Libby and Troy this week to discuss the toxicity values and risk assessment.

The toxicity values, as well as exposure data collected in Libby and Troy, were used to develop the risk assessment.

Both reports set the stage for developing a plan for managing asbestos in Libby and records of decision that will dictate final cleanup actions for the mine site and other areas within the Libby Superfund site. 

The risk assessment shows that EPA’s indoor and outdoor cleanups have been effective in reducing both the cancer and non-cancer risks in Libby and Troy. It includes an estimate of the amount of Libby asbestos — 90 fibers per cubic meter — that a person can breathe every day for a lifetime without any likely adverse non-cancer health effects.

Non-cancer effects from asbestos exposure include diseases such as asbestosis (a formation of scar tissue in the lung) as well as plaques in the lungs and thickening of the lung lining.

This is the first such estimate regarding non-cancer effects for any type of asbestos, McKean said. 

The assessment, a complex 378-page document, finds that Libby’s unique amphibole asbestos is cancerous to people when inhaled and provides a quantitative estimate of cancer risk.

A total of 3,600 people in the Libby area have been diagnosed with pulmonary asbestos-related disease and 340 have died.

The assessment of cancer effects from asbestos exposure is based on probability. The study ranks the risk of getting cancer on various activities and locations within the Superfund site.

Because exposure is associated with dust, remedial action will focus on managing source concentrations as well as activities and their locations.

Higher risks are associated with significant soil excavation and dust generation or hiking in areas such as Rainey Creek near the mine, where elevated concentrations of Libby amphibole asbestos remain.

Risks also are elevated for career contractors working in areas with vermiculite, the report noted.

Since 2000, about 1.2 million tons of asbestos-laden soil have been removed and replaced with clean soil within the Libby Superfund site. Cleanup costs have topped $400 million.

More than 2,060 properties have been cleaned. Roughly 7,200 properties have been investigated for potential contamination, including 650 during this calendar year.

About 600 properties still need to be probed and about 400 sites are owned by property owners who have refused cleanup. 

Many of those who declined to have their properties cleaned wanted to wait until the federal toxicity report was issued along with a record of decision outlining a cleanup strategy for the area in which they live, according to EPA Remedial Project Manager Mike Cirian.

Rebecca Thomas, remedial project manager team leader, said the take-home message of the risk assessment report is that Libby area residents should have their homes and yards cleaned by the EPA.

The federal environmental agency has been working in Libby since 1999. Libby was placed on the Superfund National Priorities List in 2002.  In 2009, EPA and the U.S. Department of Health and Human Services declared the country’s first-ever public health emergency at the Libby Superfund site. 

Online:

To read the final toxicity assessment, draft risk assessment and other documents, go to www2.epa.gov/region8/libby-asbestos.

For more information about the final health assessment for Libby amphibole asbestos, go to www.epa.gov/iris.

Features editor Lynnette Hintze may be reached at 758-4421 or by email at lhintze@dailyinterlake.com.