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Consistent with the Obama Administration’s “focus on ensuring that [the Marcellus Shale] resources continue to be developed safely and responsibly,” the Occupational Safety and Health Administration (“OSHA”) recently issued a Hazard Alert warning of the dangers of crystalline silica (silica dust) exposure in fracturing operations. Hazard Alerts are not a standard or regulation and create no new legal obligations. They contain recommendations, as well as further explanations of mandatory safety and health standards (and other regulatory requirements). The recommendations are advisory in nature and informational in content and are merely intended to assist employers in providing a safe and healthful workplace. Such Alerts, however, have occasionally been offered by OSHA in support of its issuance of citations under the General Duty Clause of the Occupational Safety and Health Act.

OSHA has jurisdiction over the safety and health of workers involved in upstream oil and gas operations and has taken the position that OSHA's General Industry Standards (see 29 CFR § 1910), as well as the General Duty Clause, apply to the upstream industry. With respect to OSHA’s present respirable dust regulation, OSHA's “Permissible Exposure Limit” (“PEL”) for quartz (the common form of crystalline silica found in sand) is 10 milligrams per cubic meter of air (mg/m3), which is calculated based on an eight-hour time-weighted average exposure to respirable dust. By contrast, the National Institute of Occupational Health and Safety’s (“NIOSH”) “Recommended Exposure Limit” (“REL”) is a non-mandatory, recommended occupational exposure limit, currently set at 0.05 mg/m3.

OSHA’s silica dust Hazard Alert follows a two-and-a-half-year study conducted by NIOSH that obtained 116 full-shift air samples from hydraulic fracturing operations at 11 sites in five states (Arkansas, Colorado, North Dakota, Pennsylvania and Texas). Those samples reported the following results:

  • 47% showed silica exposures greater than the OSHA PEL of 10 milligrams per cubic meter of air (mg/m3).
  • 79% showed silica exposures greater than the NIOSH REL of 0.05 milligrams per cubic meter (mg/m3).
  • 9% of all samples showed silica exposures 10 or more times the OSHA PEL, with one sample more than 25 times the PEL.
  • 31% of all samples showed silica exposures 10 or more times the NIOSH REL, with one sample more than 100 times the REL.

The study identified seven primary sources of silica dust exposure during fracturing operations and found that workers downwind of sand mover and blender operations, especially during hot loading, had the highest silica exposures. Silica dust is hazardous because, when inhaled, it causes silicosis, a disease in which lung tissue reacts to trapped silica particles, causing inflammation and scarring and ultimately reducing the lungs’ ability to take in oxygen. Silicosis has also been linked to lung cancer and other serious diseases.

Among the recommended solutions to silica exposure unearthed by the NIOSH findings, OSHA has emphasized that the use of alternative proppants (e.g., sintered bauxite, ceramics, resin-coated sand) may significantly reduce silica exposure. Admittedly, however, the use of alternative proppants may not be feasible and, therefore, OSHA recommended the following five (5) changes to current industry practices to reduce silica dust exposure:

  • Monitoring air quality to determine exposures to silica;
  • Controlling dust exposures by improving existing engineering controls (such as capping of unused fill ports on sand movers, applying fresh water to roads and around the well site to reduce the dust and constructing enclosures to contain dust);
  • Providing respiratory protection when needed (warning, however, that many types of face masks cannot protect against some of the high levels of dust revealed by the NIOSH findings);
  • Providing training and information to workers about the hazards of silica; and
  • Providing medical monitoring for workers who are exposed to silica.

The full Hazard Alert is located at:

Although not a binding regulation or compliance standard, this latest Hazard Alert is surely an indicator of where OSHA may focus its inspection efforts as drilling continues in the Marcellus Shale Region and elsewhere, and OSHA may use it to support General Duty Clause violations when citing employers.