Navigating Silica-Don’t be Caught in the Dust

October 24, 2017

OSHA, Safety & Loss Control

As we have been discussing these last few months, the new silica standard in construction establishes an 8-hour time weighted average (TWA) permissible exposure limit of 50 µg/m3 and action level of 25 µg/m3. OSHA has been enforcing the standard since September 23rd, but, for the first 30 days OSHA was offering compliance assistance in lieu of enforcement for employers making good faith effort to comply. Effective October 23rd OSHA began fully enforcing all provisions of the standard. Until a compliance directive becomes available OSHA Compliance Safety and Health Officers (CSHOs) are using interim enforcement guidance. This document demonstrates how the CSHO will check for compliance of the new silica standard in the field. The interim guidance will expire when the compliance directive becomes effective and available to the field CSHOs.

In addition, due to the new requirements silica exposures, OSHA has revoked their national emphasis program on crystalline silica. However the inspection procedures for both general industry and maritime will remain unchanged until the compliance date for these industries begin on June 23, 2018.

Materials like stone, asphalt and concrete contain crystalline silica. Activities such as abrasive blasting, cutting, sanding or drilling these materials can result in exposure to respirable crystalline silica dust. It is highly recommended to use controls available for some of these tasks outlined in Table 1 of the silica standard. The enforcement guidance states that if the employer fully and properly implement the engineering controls, work practices and respiratory protection listed in the table, it is not required for the CSHO to conduct exposure assessments of the work environment.

For contractors performing tasks outside of Table 1, OSHA has outlined alternative control measures to protect employees from silica exposure. If you are performing a task that falls outside of Table 1, and the compliance officer feels there is potential exposure, they will review your sampling data and control plan.  In addition, they will perform their own exposure assessment to determine the 8-hour TWA for the operations.

For both control measures, Table 1 or alternative controls, there are other requirements of the standard that include:

  • Establishing and implement a written exposure control plan which identifies task and procedures to restrict access to work areas were high exposure may occur.  Per the enforcement guidance document OSHA compliance officers are required to review the written plan along with any other related programs such as a hazard communications program and a respiratory protection plan.
  • Designate a competent person to implement the written exposure control plan.  It should be noted that employees working onsite should be familiar with who this competent person is if asked.
  • Offer medical exams that include chest x-rays and lung function test. This must be performed every three years for workers who are required to wear a respirator for 30 days or more per year.
  • Train workers on operations that result in silica exposures and what is the limit exposure.
  • Keep records of workers’ silica exposure and medical exams.

As always if additional assistance is needed please reach out to the J.W. Terrill Loss Control department at


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