What is the OSHA Silica Standard?
The OSHA standard for respirable crystalline silica mandates that employers limit worker exposures to an Action Level of 25 micrograms per cubic meter of air (µg/m3) and a Permissible Exposure Limit (PEL) of 50 µg/m3 over an 8-hour time-weighted average.
For the construction industry, OSHA recognized that air monitoring on constantly changing job sites is difficult. Therefore, they created 'Table 1: Specified Exposure Control Methods When Working With Materials Containing Crystalline Silica' to simplify compliance.
Understanding OSHA Table 1
Table 1 matches common construction tasks (like sawing, drilling, or grinding concrete) with specific engineering controls, work practices, and respiratory protection. If an employer fully and properly implements the controls specified in Table 1 for a given task, they are not required to measure workers' silica exposure and are not subject to the PEL limit.
For example, when using a handheld power saw to cut concrete indoors, Table 1 specifies that the tool must be equipped with an integrated water delivery system, and the operator must wear a respirator with an Assigned Protection Factor (APF) of 10.
The Written Exposure Control Plan
Even if an employer follows Table 1 perfectly, OSHA mandates the creation of a Written Exposure Control Plan. This document must detail all tasks that involve silica exposure and the specific engineering controls, work practices, and respiratory protection used to mitigate each one.
The plan must also include housekeeping measures used to limit exposure, such as prohibiting dry sweeping or the use of compressed air for cleaning dust. It must detail the procedures used to restrict access to work areas to minimize the number of employees exposed to silica.
- Description of workplace tasks involving silica exposure.
- Specific engineering controls and PPE for each task.
- Housekeeping practices to prevent dust accumulation.
- Methods to restrict access to high-exposure work areas.
Competent Person and Recordkeeping
A critical element of the written plan is the designation of a 'competent person.' This individual must be capable of identifying existing and foreseeable respirable crystalline silica hazards and authorized to take prompt corrective measures to eliminate them. The competent person must frequently and regularly inspect job sites, materials, and equipment to implement the written control plan.
Employers must review the written exposure control plan at least annually to ensure it remains effective, and maintain accurate records of any objective data or air monitoring relied upon.
Frequently asked questions
If I follow Table 1 exactly, do I still need to do air sampling?
No, if you fully and properly implement the engineering controls, work practices, and respiratory protection specified in Table 1, you are exempt from the air monitoring requirements.
What happens if a specific task isn't listed on Table 1?
If a task is not on Table 1, or if you cannot fully implement the required controls, you must perform air monitoring to assess employee exposure and ensure it remains below the PEL.
What is an APF for respiratory protection?
APF stands for Assigned Protection Factor. An APF of 10 typically indicates a half-mask respirator, while an APF of 25 or 50 indicates a full-facepiece or powered air-purifying respirator (PAPR).
Does the written control plan need to be accessible to employees?
Yes, OSHA requires that the Written Exposure Control Plan be readily available for examination and copying by affected employees, their representatives, and OSHA inspectors.