For manufacturing these types of gaskets, asbestos was heavily used for nearly a century. Even though chrysotile (white asbestos) was used in the majority of cases, crocidolite (blue asbestos) was preferred when the gasket needed to be resistant to acid.
Containing up to 70 percent asbestos in their composition, gaskets were extremely dangerous when they required replacement. Due to being extremely damaged, they needed to be scraped off, and by doing that, asbestos fibers would quickly contaminate the environment. You could have been exposed if: