Asbestos Use in Roofing Products
It seemed good business sense to add asbestos to roofing products—for practical reasons, that was.
First, adding 15-20% asbestos fibers into the petroleum asphalt mixture cured the fire problem.
Shingles containing asbestos were inflammable, and that was highly popular with civic planners and insurance companies.
Using asbestos in roofing had many other advantages:
- It was lightweight. That solved structural issues for heavy roof loads.
- Asbestos particles made asphalt-based roofing durable and long-lasting.
- Asbestos wouldn’t rot, rust, conduct electricity, or react to heat.
- Asbestos was easy to work with, widely sourced, and low-cost to purchase.
Builders across the country heartily endorsed asbestos roofing as the best material on the market.
Shingles weren’t the only roof product containing asbestos materials. In fact, most other roofing products produced in the early to mid-twentieth century contained asbestos. It was a universal solution to roof concerns.
Asbestos fibers found their way into these roofing products:
- Roofing tar and asphalt liquids
- Roofing felt and underlayment
- Roofing caulking, mastic, and sealant
- Roofing cement and cement-based shingles
- Roof flashings and vents
- Roof flat-sheets and corrugated asbestos roofing
Roofing manufacturers blended two types of asbestos fibers into their products. Most common was chrysotile or white asbestos. The other kind was amphibole asbestos fibers.
There’s a distinct difference between the two. Another name for Chrysotile fibers is serpentine asbestos. Microscopically, they’re long and twisted with soft edges. Amphibole fibers were a group of asbestos particles or subclass. They’re crystalline with sharp, spiny structures and far more dangerous when inhaled.
The U.S. Environmental Protection Agency (EPA), along with the Occupational Safety & Health Administration (OSHA) was aware of how dangerous exposure to airborne asbestos fibers was to roofing product manufacturing employees and installation workers.
The 1989 Asbestos Ban and Phase Out Rule put an end to filling roofing products with deadly asbestos fibers that caused diseases like mesothelioma.