New Federal OSHA Guidelines for Respirable Crystalline Silica (RCS)

By MC&MCA Member Paul Serafini of Sotera Consulting, LLC

After decades of chatter, Federal OSHA has published their long-awaited regulations for Respirable Crystalline Silica. 

The rules are published in the Federal Register, and are in effect as of June 2016 (including in Minnesota).  However, construction employers are not obligated to comply until June 2017.

Unless one of the current legal challenges to the rule are successful (don’t hold your breath), construction employers in Minnesota and elsewhere will be expected to be in compliance by June, 2017. 

Here are a few highlights:

No need for air sampling/monitoring?

Unlike similar regulations, OSHA will not require most employers to conduct air monitoring to assess employees’ exposures to Respirable Crystalline Silica (RCS).

Instead, OSHA has developed a table which lists 28 typical tasks/types of equipment commonly found on jobsites, and designated the controls required for each, including the need for respiratory protection.

In some cases, employers may also be permitted to use “objective data,” such as industry studies and tests, to assist in assessing exposures.


Permissible Exposure Limit cut in half and Action Limit created

Under the new rule, the PEL for RCS has been reduced to 50 ug/m3. A new Action Limit or AL of 25 ug/m3 has also been created. Employees who have exposures above the AL, but below PEL, will have limited coverage under the    regulation.

Engineering controls

For decades, experts have understood the importance of minimizing RCS dust through means such as dust collection and wet cutting. The new regulation takes these “best practices” and makes them mandates.

The regulation is full of new requirements for the use of HEPA vacuums, wet cutting, enclosures/booths/cabs, and   other controls. Table 1 mandates various types of engineering controls for the tasks and equipment it outlines, but there are many additional requirements throughout the rule.

Respiratory protection

When engineering controls aren’t feasible or they fail to adequately control exposures, appropriate respiratory         protection will be required. The type of respirator required will depend on the exposures at hand.

Any employee who wears a respirator will need to be included in a formal, written respiratory protection program that complies with 1926.103.

Written exposure control plan

Employers covered by the rule will also be required to develop a written exposure control plan, which explains how exposures will be minimized. All employees, their designated representatives, and OSHA must be granted access to   the program.

“Frequent and regular inspections” by a competent person

“Frequent and Regular” jobsite inspections by a competent person are required to ensure that the requirements under the exposure control plan are being complied with.

Medical surveillance

Employees who are covered by the regulation and who wear respirators more than 30 days per year must be entered in a medical surveillance program. Examinations will be required at the time of assignment to a job that is covered by the regulation, and at least every three years thereafter.

The regulation outlines the content for the examinations, but one requirement which will be troublesome is that the examination must include a chest x-ray. This will be difficult for many employers, especially if they use a mobile testing service for their health needs. 

Training and communication

Employers must include RCS in their written Hazard Communication program and training. In most states, including MN, annual refreshers will be required.


If you have questions about the new regulation, or need help with exposure assessments, training, development of the exposure control program, or anything else, please call Paul at Sotera Consulting, LLC at (612) 597-6463 or email

Sotera Consulting, LLC is offering a 15% discount on all services to MC&MCA members.