Understanding the OSHA silica standard 

by LIZ MEDINA ALM, MD, MPH 

Occupational Safety and Health Administration (OSHA) recently changed some of the rules for its silica standards. Many employers and companies are now asking, “What exactly has changed, and how does this affect me?” 

Silica, one of the most abundant minerals on earth, is an oxide of silicon (SiO2) that exists in a non-crystalline (amorphous) form, but is far more prevalent in its crystalline structure (e.g., quartz). Crystalline silica may become respirable (able to be inhaled) when materials that contain the crystalline structure are cut, drilled, crushed or ground. 

Respirable exposure to silica particulates is associated with an increased risk for pulmonary diseases, such as silicosis, chronic bronchitis, chronic obstructive pulmonary disease (COPD), kidney disease and lung cancer. As crystalline silica is a common component of sand, stone, rock, concrete, cement, grout, tile, drywall and brick; many industries are potentially affected by this change to the OSHA standards. 

OSHA’s previous silica standards were developed more than 40 years ago. In March 2016, after years of research and review, OSHA published a final rule change to those standards. The OSHA silica standards can be found under Title 29 of the Code of Federal Regulation (§1926.1153).

This change pertains to both general industry and construction.

Highlights of the new OSHA silica standard include: 
• Defining the airborne respirable crystalline silica action level as a concentration of 25 μg/m3 over an 8-hour time-weighted average (TWA) 
• Reduction of the permissible exposure limits (PEL) for respirable crystalline silica to 50 μg/m3, averaged over an 8-hour TWA (previously 100 μg/m3 in general industry and 250 μg/m3 in construction) 
• Requirement of employer use of engineering controls (e.g., ventilation), offer personal protective equipment (e.g., respirators), develop written exposure control plans, provide medical exams to highly exposed workers, and institute training for workers on silica risks and how to limit exposures 
• Provisions to help employers, especially small businesses, protect workers from silica exposure 

This rule change was implemented June 2016, with compliance required by June 2017 for construction and June 2018 for general industry. The goal is to significantly reduce the amount of silica dust that workers are exposed to on the job. Technology is widely available and affordable for most employers to meet the new standards. Many employers are already implementing the necessary measures to protect their workers from silica exposure. 
Visit osha.gov/silica for more information on OSHA’s silica standard, including resources for employers.