Asbestos is a fibrous material that was a popular method of insulation for hundreds of years. The main reason it works so well is that it’s highly resistant to heat and chemicals. It’s also quite cheap, and can easily be mixed with cement and fabric.
There’s just one problem: breathing the substance can result in terrible health problems, most notably lung cancer and mesothelioma.
The first known death was in 1906, when a man living in an asbestos mining town mysteriously keeled over. This was followed by several hundred more deaths, usually accompanied by hacking and wheezing, which prompted scientists to search for the common link. They soon discovered the health hazards involved, and news was spread, but people still continued to use asbestos. Seriously, you’re not going to find insulation at that price anywhere else!
It wasn’t until 1989 that the U.S. banned use of the substance. They issued the Asbestos Ban and Phase Out Rule, which required companies to stop filling people’s homes with the toxic material. This was overturned by the high court two years later, however, and nowadays many businesses still sell objects that contain trace amounts of asbestos. These products tend to be only sold to poor people, however, so it’s probably not worth getting worked up over.