Asbestos at a Glance
Asbestos is a metamorphic mineral mined from the earth. Asbestos is a fibrous or thread-like mineral that was commonly woven into clothing made by the Greeks and Romans. Russia and China are the leading producers of asbestos, while Russia, China, India, Russia, and Thailand are the world?s largest users of asbestos. For the most part, asbestos use in the United States has been in dramatic decline since the 1970s. Health concerns surrounding asbestos, however, have existed since the Greeks first began using the mineral over 2000 years ago.
There are six types of asbestos that can be classified into two main groups. Both are fibrous and similarly toxic, but to varying degrees.
The first group is made up of only one type of asbestos. Crysotile (?white asbestos?) asbestos is the only member of the serpentine asbestos group. Crysotile asbestos means ?gold fiber? in Greek and gets is name because the early Greeks valued asbestos for its mystical, fire-resistant powers.
The second group, the amphibole group, has six types: actinolite, amosite (brown), anthophyllite, crocidolite (blue), and tremolite. Prior to 1975 ? and in addition to crysotile asbestos ? anthophyllite, amosite, and crocidolite asbestos were commonly used for industrial purposes.
Asbestos Use in Construction
Asbestos was often used in buildings as insulation and to help localize a fire and prevent it from destroying the entire structure. However, the most common use for asbestos was as a cement additive. By adding asbestos to a mixture of cement, the tensile strength of a sheet of cement would be increased 10 fold. Thus, by adding asbestos, construction companies were able to use and transport less cement, cutting the cost of a project significantly.
Between the middle of the Great Depression and the 1970s, asbestos was commonly applied to walls, ceilings, and pillars in a spray form. This use has been shown to have been the most dangerous. Similarly dangerous was a use called lagging which utilized a fibrous form of asbestos that resembled ?dust-bunnies? to prevent heat diffusion and increase energy efficiency. Other construction uses include insulation boards, slating, tiles, and the lining behind fireplaces.
Asbestos Use in Shipyards
Shipyards started using asbestos for insulation around piping in the 1940s. Asbestos was ideal for ships because of its low cost, light weight, and ability to withstand high heat and corrosion from moisture. Everything on the ship from engines to boilers to stoves were encased in asbestos. Early signs of the health dangers like mesothelioma led the US Navy to impose guidelines on proper handling of asbestos.