Silica is created when silicon and oxygen combine. These minerals are called silicates and comprise about 90% of the Earth’s crust mass. That means most people come in contact with some form of silica each day, but, like asbestos, the undisturbed mineral is not the danger, it’s the dust caused by disturbing the mineral.
The danger of inhaling silica has been known for over 400 years, first described by Agricola in 1556 in his “Treatise on Mining.” He recognized it as a pulmonary disease acquired by miners and stonecutters. The danger of silica dust was known even before the hazards of asbestos. Now, with more advanced, high pressure power and air equipment equipment used in fracturing, mining, sandblasting and other industrial occupations, it has become even more of a health issue. At the beginning of the Industrial Age, these early warnings from the distant past were largely forgotten, or ignored, but during the Depression, thousands of workers in trades producing airborne silica sued employers for damage due to exposure. A 1931 incident, the Gauley Bridge disaster, brought silicosis to the forefront as 476 workers died from the disease brought on by blasting a tunnel.
In spite of knowing the dangers, companies continued working with silica without warning workers of the dangers from the ‘40s through the ’60s. Finally, in 1971, OSHA created workplace exposure regulations for both silica and asbestos. While the asbestos standard has been strengthened over time, the exposure limit for silica remained unchanged until now. The 1971 limit was 250 micrograms per cubic meter of air, on average, over an eight-hour shift for construction and 100 micrograms for other industrial uses. Now, starting June 23, 2016, the limit of 50 micrograms for all uses will go into effect. The industries affected by the new regulation will have from one to five years to fully comply, however.
Three industry groups – construction, maritime, and general industry – fought the new standard citing difficulties in compliance and a cost in the billions. The lower limit will potentially save 600 lives and prevent 900 illnesses each year, according to OSHA.