The Zonolite Company began extracting vermiculite in 1924 from a mine on what would come to be known as Zonolite Mountain. The mineral was used, among other things, in potting soil and insulation, but it was not pure. One other agent that was mined out right along with it was tremolite asbestos, and it's this asbestos that's causing health problems.
There are many kinds of asbestos, but tremolite has one of the smaller, more dangerous fibers. It can be hard to detect in air samples regularly used to test for asbestos -- this is one of the reasons the on-site EPA coordinators in Libby are pushing to change the agency's standards for tremolite.
Mine workers and workers at the expansion plant -- where the vermiculite was being turned into Zonolite insulation -- were directly exposed to tremolite fibers in the air, and their families were exposed to the tremolite dust they carried home on their work clothes.
But millions of other people to this day may still be exposed to the tremolite asbestos found in Zonolite Attic Insulation. This granular product -- it looks a little like mica -- was very popular prior to it being taken off the market in 1984. Today it can still be found in attics across the country. Does that mean anyone who lives underneath an attic that's insulated with Zonolite is going to develop asbestosis?
"In many cases, the information being provided in the media is incomplete," says Ron Knutson, division manager of MSC Environmental Services in Spokane, an engineering company that does asbestos testing. "It goes something like this: 'If I have Zonolite in my attic, I have trouble' -- that is not necessarily correct. Typically, the Zonolite that we test has a fairly low asbestos content, less than two percent. As long as you leave it alone and don't crawl around in it drawing cables or drilling holes, you should be fine."
Asbestos fibers have to be either ingested or breathed in to cause physical harm. That's why the EPA stated over and over again to the people in Libby that they should not try to clean out their own attics. Sweeping, vacuuming or shoveling asbestos contaminated materials releases asbestos fibers into the air, and down into the lungs of the people present. Once inside the lungs, the fibers stay put and cause increasing damage as time goes by.
The Spokane Regional Health District provides general information on asbestos precautions that have been approved by the EPA, but does not have any special information on Zonolite.
Knutson says people should get their insulation checked out if they don't feel safe, especially if their house is more than 25 years old. "Prior to '78, we tend to have more asbestos associated with building materials," he says. "Every so often, you hear about new houses with asbestos in them, too. There are about 4,000 building materials with asbestos in them." And he agrees with the EPA: Removing asbestos is no do-it-yourself project.
"You need a licensed asbestos abatement contractor to take the stuff out," says Knutson. "If you try to do it yourself, you are just going to spread the contamination."