Crystalline silica, a mineral in the earth’s crust, is a common component of sand, stone, concrete, and brick. When workers cut, saw, or drill these materials—mainly during construction work and mining operations—the silica is aerosolized, exposing workers to fine particulate dust. Once inhaled, long-term exposure to the crystalline silica particles causes silicosis, a fatal lung disease, as well as chronic obstructive pulmonary disease, kidney and immune system diseases, and lung cancer.
Exposure to silica dust is one of the oldest known workplace hazards. In the 1970s, over one million workers were exposed to silica dust daily in construction, manufacturing and mining jobs. By 2013, this figure had jumped to almost two million. Even though the number of silicosis cases has declined, the Department of Health and Human Services estimates that the number of silicosis-related deaths among those aged 15-44 has remained relatively stable, and that those exposed over the course of a 40-45-year career still have a 1 in 100 chance of developing silicosis at the current permissible exposure limits. Silica is regulated by the Occupational Safety and Health Administration (OSHA), 
which sets workplace standards based on a Permissible Exposure Limit (PEL), or the maximum exposure over a given time period. While the International Agency for Research on Cancer classifies silica as a carcinogen, the National Institute for Occupational Health continues to recommend a PEL of 0.05 mg/m3 per 40-hour workweek (29 CFR 1910). This federal standard, set in 1974, is based on data and technology from 1968.
In February 2011, thirty-seven years after it began regulating silica, OSHA proposed new regulations that halved the limit for workplace exposure. The National Advisory Committee on Occupational Safety and Health (NACOSH) agrees it is time for a change: “The current standard is many decades old and is insufficient to protect workers from this serious occupational health hazard.”
From the Centers for Disease Control
However, the White House Office of Management and Budget (OMB) has blocked any hope for change. It was expected to review the proposed rule and post it for public comment within 90 days. Two years later, despite NACOSH’s urging, OMB has failed to take any action on the proposal. This delay comes at a cost: According to Peg Seminario, AFL-CIO Director of Safety and Health, “[e]very year this rule is delayed, another 60 workers will die.”
Many have begun to suspect that the reason behind OMB’s delay is political. A reduction in standards for workplace exposure of silica dust would affect a significant portion of the construction and mining industries, which have voiced concerns that tighter regulations would lead to higher production costs. Even more troubling are recent findings that hydraulic fracturing exposes workers to high levels of silica dust, often higher than the current federal standards. Given that the U.S. has become increasingly reliant on hydraulic fracturing for its energy needs, the portion of the workforce exposed to dangerous levels of silica dust on a daily basis has significantly expanded.
Video, produced in 1938 by the U.S. Department of Labor, demonstrates the dangers of exposure to silica dust.