The U.S. Environmental Protection Agency is investigating whether products made from vermiculite could expose consumers to asbestos. Preliminary test results on common household products indicate that a particularly lethal form of asbestos fibers contaminates some attic insulation, but researchers do not yet know whether normal use of these products could endanger consumers.
Asbestos is a generic term used to describe a number of fibrous minerals including actinolite, amosite, anthophyllite, chrysotile, crocidolite and tremolite. Of these, scientists believe tremolite -- one of the rarer forms -- is the most dangerous. The sharp needle like fibers of naturally occurring tremolite easily penetrate the linings of the lungs. The lungs are unable to remove these tiny spears, which cannot be coughed out or washed out of the lung tissues by blood.
Lungs infected with tremolite become inflamed and eventually scarred, a condition called asbestosis. Heavily scarred areas can no longer function, and victims become unable to breath effectively, because oxygen cannot get into the lungs and carbon dioxide and other impurities cannot get out.
The vermiculite ore at a mine in Libby, Montana, was contaminated with tremolite.
For more than 60 years, W.R. Grace &amjp; Co. dug vermiculite ore out of the Zonolite Mountain in Libby. Vermiculite is a volcanic mineral compound that expands when wet. It is used in agricultural, construction, horticultural and industrial applications, including pesticides, insulation, potting mixes, brake pads, sound deadening materials, fire protection, paints, sealants, insulating concrete and nuclear waste disposal.
At least 192 people in Libby have died over the past 40 years from asbestos related illnesses linked to the Zonolite mine. Most died of asbestosis, lung cancer or mesothelioma, a cancer of the lung lining. More than 375 other people in Libby have also been diagnosed with asbestos related diseases.
The company has been sued by nearly 200 former workers or their families, and is now the subject of a class action lawsuit representing some 26,000 people exposed to asbestos from contaminated vermiculite ore, including mineworkers, processing plant employees and Libby residents.
W.R. Grace, which bought the Libby mine from the Zonolite Corp. in 1963, sold vermiculite based attic insulation under the name "Zonolite," but discontinued sales in 1984. The Environmental Protection Agency (EPA) is concerned that homeowners could be exposed to the tremolite fibers in Zonolite during renovations or remodeling.
EPA has found asbestos contamination in some Grace fertilizer products, also marketed under the name Zonolite, and in other garden and lawn products as well.
The EPA's laboratory in Manchester, Washington has installed a new facility with air monitoring equipment to test vermiculite products. The agency is trying to learn whether normal use of these products could release asbestos into the air, where it could be inhaled by consumers.
Concerns about the health affects of asbestos contaminated vermiculite products date back to the 1970s. In a 1991 report, the EPA said that 188,000 people had been exposed to asbestos contaminated attic insulation, 32 million to garden fertilizer and 74 million to other vermiculite lawn products. The agency did not draw conclusions regarding the health risks of the exposures, but recommended further studies. These studies were never funded.
In 1981, the EPA concluded that consumers using Zonolite attic insulation "may be particularly vulnerable and unprotected due to ignorance of the potential hazard." However, the agency did not release a public warning about the product until this month.
W.R. Grace, though warned by the EPA that it might need to add a label to the insulation warning of the asbestos content, also did not inform consumers of the possible risk.
Until the new studies are completed, the EPA is recommending the same cautions it applies to any asbestos containing materials. Consumers are cautioned to avoid disturbing insulation in their homes that might contain vermiculite.
If Zonolite or another vermiculite containing insulation must be removed, homeowners should use respirators that include High Efficiency Particle Arresting (HEPA) cartridges. Paper face masks commonly sold in hardware store will not keep asbestos fibers out of the lungs, EPA warns.
W.R. Grace, once the nations largest producer of vermiculite lawn and garden products, still sells vermiculite from a mine in Enoree, South Carolina, which it says is not contaminated with tremolite. The mine in Libby has been shut down since 1990.
The EPA has created a website with information regarding the Libby, Montana mine, available at: http://www.epa.gov/region08/news/erlibby/libby.html
- 190 Natural Resources