Gaskets are used in many different products to fill the space between two pieces of equipment. A gasket provides a seal that will prevent leakage, especially when the equipment is under compression. In a car engine, for example, gaskets seal the cylinders to prevent coolant or engine oil from leaking.
From the early 1900s through the 1970s, gaskets were often made from asbestos. This natural family of minerals possessed many qualities which made it an ideal material for construction, manufacturing and automotive materials; it was inexpensive, strong, durable, heat resistant and an excellent insulator. Chrysotile, or “white” asbestos, was the form most commonly found in gasket materials.
As more evidence surfaced about the health hazards of asbestos, it fell out of favor as a manufacturing material and was eventually banned in many applications by the Environmental Protection Agency (EPA). The properties that made asbestos so desirable in manufacturing were outweighed by the problems caused by asbestos. The small, tightly packed asbestos fibers are fine as long as they remain bound. If the asbestos-containing gasket is damaged in any way, even by cutting or drilling, then the fibers can be released into the air. Because they are so small, they are easily inhaled and can lodge in the lungs. Diseases such as asbestosis, or scarring of the lungs, or various forms of cancer can develop up to thirty years after exposure. The risk of developing these diseases increases with the number of fibers inhaled, or the amount of time of exposure; smoking also increases the risk.
Although there are a wide variety of other materials now used to make gaskets, the EPA still allows asbestos to be used in gaskets and other automotive applications, such as brake linings, since the fibers are usually tightly bound in the material. Millions of cars in use today have asbestos-containing gaskets in their engines. Asbestos-containing gaskets look no different than those without asbestos, so unless you have looked at a manufacturer’s part list for your car, it is safest to assume that the gaskets in your engine contain asbestos.
Even the most accomplished home mechanic needs to be careful when replacing or repairing potential asbestos-containing parts. Professional repair shops usually have the proper safety and disposal equipment to work with these parts, so they are the preferred choice. If you choose to handle these types of gaskets yourself, be sure you use the correct equipment and procedures as recommended by your local EPA office.