Asbestos refers to a group of minerals that were very popular for a time largely because they are resistant to fire. This obviously makes them useful for a wide variety of things, from brake shoes to stage curtains to building materials—including popcorn ceilings. However, in 1978, the manufacture of ceiling texture that contained asbestos was prohibited, but companies were allowed to use up any existing supplies they already had. As a result, ceilings that were textured in 1978, and possibly for several years after that, did contain asbestos.

Why is it dangerous?

Asbestos consists of long, thin fibers that can easily become airborne. One of the most common afflictions experienced by people exposed to asbestos is called asbestosis. When asbestos fibers are inhaled, they become lodged in your lung tissue. The body then tries to eliminate the fibers by producing an acid. Although this acid has little effect on the asbestos fibers, it does scar the surrounding tissue. Since the fibers remain in place, the body keeps producing acid, and the scarring of the tissue gets worse. After a long enough time, the lung can stop functioning.

As you can imagine, it can take a while for asbestosis or other effects of asbestos exposure to appear—up to 30 years, in fact. The key is to protect yourself from any unnecessary exposure.

For more information, check out the EPA's (Environmental Protection Agency's) Web site or the useful information prepared by the American Lung Association.