Asbestos was once used to make many common products including insulation, roofing materials, automobile brake pads, and other household and commercial goods. In the 1960s asbestos was used in the petroleum industry, where the the high heat-resistance of asbestos made it a useful additive to drilling mud. Drilling mud is used while drilling oil and gas wells to help clear debris out of the well and to help cool the drill bit. Various substances are often added to the drilling mud to adjust its thickness and fire retardant properties. Many of these, including lead, arsenic, and chromium, are toxic. Asbestos provided superior fire resistance and helped to improve the mud’s consistency. Unfortunately, we now know that asbestos is linked to several types of cancer and other health problems.
The use of asbestos in drilling mud has been eliminated today; however, when it was first prohibited by the U.S. government, some petroleum companies apparently took the position that the federal ban did not apply to their offshore oil rigs or inland drilling barges. Thus, asbestos products could have been used in these environments even as late as the mid-1980s. Many drilling workers can recall working with a white, flaky additive that was in 50-pound packages and added to the drilling mud in the mud shack. No proper breathing protection was provided to the workers who handled the mud additives, so many of these workers routinely inhaled pure asbestos fibers while mixing in the additives. Other oilfield workers such as roughnecks, mud engineers, and shaker hands also were likely exposed to asbestos on a regular basis during this timeframe. Even spouses and children of drilling workers were at risk of exposure if the workers came home with asbestos fibers clinging to their clothing.
Asbestos fibers are known to cause or increase the risk of many forms of cancer. The danger is highest among smokers, who face a substantially increased incidence of lung cancer. Studies have also shown a connection between asbestos exposure and gastrointestinal cancer, colorectal cancer, and a heightened risk for cancers of the throat, kidneys, esophagus, and other organs. Exposure is also linked to inflammation of the lungs, known as asbestosis, as well as pleural disease, which is inflammation of the tissue layers that line the lungs.