This short documentary on the history of asbestos is very interesting. It can really make you think about current chemicals, GMOs, and manufactured materials that we are using in society today. It took over one hundred years from the time asbestos was first recognised as causing health concerns, to the time that asbestos was banned. Asbestos is still used in places like India!
The remnants of asbestos will be found in the United States for years to come. That is one of the reasons why filtration is so important to the ThermaPure process. Please check with your heat technician and make sure that they are running a HEPA filter.