Tom Laubenthal is a leading expert on asbestos in the United States. In a recent article, he called on the asbestos industry to refer to vermiculite from Libby, MT as Libby Amphibole asbestos (LA).
LA is vermiculite from the Libby mine in Montana. The Zonolite company began mining vermiculite at Libby in the 1920s and sold the vermiculite as Zonolite. The mine was an environmental disaster. The vermiculite contained three main types of amphibole asbestos – winchite, richterite, and tremolite. Because of this, many who worked in the mine, lived nearby, or worked with the product developed asbestos-related diseases.
The mine shut down in 1990. Eventually, the EPA designated it a Superfund site and began cleaning it. At the time it was shut down, there were estimates that Libby had produced 80 percent of the world’s vermiculite. Much of the vermiculite in the U.S. came from there and likely contains asbestos.
That the vermiculite from Libby, MT can contain asbestos has been known for a long time. Yet training for asbestos workers, methods of laboratory analysis, and sampling techniques frequently do not reflect this fact. LA was widely used throughout the United States, easily disturbed and highly friable, and causes cancer. Vermiculite from Libby is Libby Amphibole asbestos. Using that term helps convey how dangerous this vermiculite is and that it needs to be treated accordingly.
The EPA first used the term ‘Libby Amphibole asbestos’ over a decade ago. They have categorized it as ‘carcinogenic to humans’. The LA designation is specific to vermiculite from Libby, Montana. So the label should not be used for other products that contain winchite, richterite, or tremolite.
In his article, Mr. Laubenthal suggests trainers adopt the LA term, adding it to their materials and teaching proper sampling methods. He repeats this in his guidance for consultants: because the asbestos-containing pieces are larger and sink, leaving the lighter vermiculite flakes on top, samples must be scooped from deep in the material. Additionally, it is important to send the samples to labs that are familiar with analyzing vermiculite.
For more info, click here to read Tom Laubenthal’s detailed article on the subject.
For more on the Libby Superfund site, click here.
