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Respirable Crystalline Silica in Construction Standard Enforcement Guidance Part 1

Respirable Crystalline Silica in Construction Standard Enforcement Guidance Part 1

On October 23, 2017, OSHA began to fully enforce the Respirable Crystalline Silica in Construction standard 29 CFR 1926.1153.  OSHA issued a memorandum (10/19/2017) to provide interim enforcement guidance to Compliance Safety and Health Officers (CSHOs) for enforcing the standard. Employers should review the memorandum to gain insight into what OSHA inspectors will be looking at during a silica in construction inspection. Construction projects involving jack hammering, rock/well drilling, concrete mixing, concrete drilling, brick and concrete block cutting and sawing, tuck pointing, tunneling operations may result in respirable crystalline silica exposure.

The standard establishes a new 8-hour time weighted average (TWA) permissible exposure limit (PEL) of 50 µg/m3, and an action level (AL) of 25 µg/m3. CSHOs are instructed to be ready to conduct personal air monitoring on the first day of the inspection to determine worker exposure to respirable crystalline silica. Respirable crystalline silica consists of particles that are smaller than 10 μm in aerodynamic diameter. The reference OSHA sampling method is ID-142.   Samples are collected by drawing breathing zone air through pre-weighed 5­ μm pore size, 37-mm diameter low ash polyvinyl chloride (PVC) filters preceded by 10-mm nylon cyclones. Gravimetric analysis is utilized to determine the weight of the respirable dust. The PVC filters are dissolved and the samples are suspended in tetrahydrofuran (THF). The samples are then placed on silver membranes and analyzed by X-ray diffraction (XRD). The sampling will typically be conducted over most of the work shift.

Respirable Crystalline Silica in Construction Standard3

CSHOs are required to review the employer’s written silica Exposure Control Plan (ECP).  The ECP should contain at a minimum: (1) a description of the tasks that involve exposure to respirable silica; (2) a description of controls for each task including engineering, administrative and personal protective equipment (PPE); (3) a description of housekeeping measures used to control worker exposure to respirable silica; and (4) a description of measures to restrict access to work areas to limit worker/contractor exposure.

CSHOs are also required to evaluate related programs including (1) respiratory protection program, (2) hazard communication program, etc.

If the employer has conducted an exposure assessment, the CSHO is required to review the assessment to determine potential exposure levels prior to entering the work area.

Employers are not required to assess the exposures (conduct air monitoring) of employees engaged in Table 1 tasks if the employer has fully and properly implemented the engineering controls, work practices, and respiratory protection listed in Table 1 for the employees engaged in those tasks.

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As with most inspections, CSHOs are directed to interview affected employees, including the competent person, as part of the overall assessment of the employer’s implementation of its ECP.  Questions asked by CSHOs may include: (1) What type of training was provided (topics) (2) When was the training provided and (3) Assess understanding of silica.  Workers on the project need to know who the competent person is. The competent person is typically the supervisor and is able to take immediate action to control onsite hazards including silica exposures.


For assistance with complying with the Respirable Crystalline Silica in Construction standard 29 CFR 1926.1153 please contact ECOthink Group. We can develop a project specific exposure control plan, conduct an exposure assessment, recommend and implement controls, provide on site or online training. For more information contact: info@ecothinkgroup.com or 646 705 1593.

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