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Employers are required to limit worker exposure to respirable crystalline silica and take necessary measures to protect workers. Crystalline silica is a common material found in construction such as concrete, brick, sand, stone, and mortar. Workers are exposed to silica during operations that involve cutting, grinding, drilling, crushing, or sweeping materials that contain silica. Crystalline silica is especially dangerous because the particles that are breathed in by workers are extremely small and can enter the lungs, causing incurable silicosis, cancer, or deadly lung disease.
Scope
OSHA’s construction respirable crystalline silica requirements apply to all workers who may be subject to occupational exposure to crystalline silica in construction work, except where employee exposure will remain below 25 micrograms per cubic meter (25 μg/m3) of air as an 8-hour time-weighted average under any foreseeable conditions.
Regulatory citations
- 29 CFR 1926.55 — Gases, vapors, fumes, dusts, and mists
- 29 CFR 1926.1153 — Respirable crystalline silica
Key definitions
- Action level: A concentration of airborne respirable crystalline silica of 25 μg/m3, calculated as an 8-hour TWA.
- Competent person: An individual who is capable of identifying existing and foreseeable respirable crystalline silica hazards in the workplace and who has authorization to take prompt corrective measures to eliminate or minimize them. The competent person must have the knowledge and ability necessary to fulfill the responsibilities set forth in paragraph 1926.1153(g).
- Employee exposure: The exposure to airborne respirable crystalline silica that would occur if the employee were not using a respirator.
- Physician or other licensed health care professional: An individual whose legally permitted scope of practice (i.e., license, registration, or certification) allows him or her to independently provide or be delegated the responsibility to provide some or all of the particular health care services required by 1926.1153(h).
- Respirable crystalline silica: Quartz, cristobalite, and/or tridymite contained in airborne particles that are determined to be respirable by a sampling device designed to meet the characteristics for respirable-particle-size-selective samplers specified in the International Organization for Standardization (ISO) 7708:1995: Air Quality—Particle Size Fraction Definitions for Health-Related Sampling.
Summary of requirements
Construction employers can either use a control method, or they can measure workers’ exposure to silica and independently decide which dust controls work best to limit exposures to the PEL in their workplaces.
Regardless of which exposure control method is used, all construction employers covered by the standard are required to:
- Establish and implement a written exposure control plan that identifies tasks that involve exposure and methods used to protect workers, including procedures to restrict access to work areas where high exposures may occur.
- Designate a competent person to implement the written exposure control plan.
- Restrict housekeeping practices that expose workers to silica where feasible alternatives are available.
- Offer medical exams — including chest X-rays and lung function tests — every three years for workers who are required by the standard to wear a respirator for 30 or more days per year.
- Train workers on work operations that result in silica exposure and ways to limit exposure.
- Keep records of workers’ silica exposure and medical exams.