Part II: Are You Ready for OSHA’s New Respirable Crystalline Silica Standard?

This is the second post in a three-part series reviewing OSHA’s new standard for respirable crystalline silica.  In part one, we mentioned that the new permissible exposure limit (PEL) for respirable crystalline silica is 50 µg/m3 with an action level of 25 µg/m3.  A series of requirements will be in effect depending on the employee’s exposure. 

Exposure Assessment   

Employers have two options to characterize the employee’s exposure.  The first option or “Performance Option” is based on a combination of air monitoring data or objective data considered to accurately characterize the employee’s exposure.  The other option is to conduct an initial monitoring assessment.  This option should consider the employee’s exposure for each job classification/shift/tasks where there is a potential for exposure to respirable crystalline silica.  If the initial assessment shows results below the action level (25 µg/m3), no additional monitoring is needed unless there is a change in the process.  If exposures are above the action level, but below the permissible exposure limit, the employer needs to repeat the assessment every six months.  If exposures are above the permissible exposure limit then the assessment needs to be repeated every three months.

What if the initial assessment indicates that exposures are above the action level and/or the permissible exposure limit and the employer invests in controls to reduce the employee’s exposure?  In that case, the employer should conduct two consecutive assessments, at least seven days apart, with results below the action level before discontinuing the scheduled monitoring. If monitoring is performed, the monitored employees should be notified in writing of the results of the assessment within 15 working days after completing the assessment.  If the results are above the permissible exposure limit, the written notification should describe the corrective action being taken to reduce exposure of the employee below the permissible exposure limit (PEL)[i].

Regulated Areas

A regulated area is an area where the airborne concentrations of respirable crystalline silica are/or are expected to be above the PEL.  Therefore, the employer should limit the access to these areas, authorized employees working in these area should wear respiratory protection, and there should be signage in the area stating “Danger, Respirable Crystalline Silica, May Cause Damage to the Lungs, Wear Respiratory Protection in This area, Authorized Personnel Only”i.

Methods of Compliance

Similar to the lead standard, this new standard requires the implementation of engineering controls and a written exposure control plan.  If exposures are above the PEL, this new standard requires employers to use engineering and work practice controls to reduce and maintain the employee’s exposures below the PEL.  If such controls cannot lower the exposure to levels below the PEL, the standard calls for continued use of these controls to lower the employee’s exposures to the lowest feasible level and then require the use of respiratory protection.   

The written exposure control plan should include the following items: a description of the tasks that involve exposures to respirable crystalline silica, a description of the controls (engineering, work practices and/or respiratory protection) for each of the affected tasks, and a description of the housekeeping practices to limit the employee’s exposure to respirable crystalline silica.  The standard calls for an annual review and evaluation of the effectiveness of this written plani.


This new standard would not allow dry sweeping and/or brushing if these activities could contribute to an increase employee’s exposure to respirable crystalline silica.  It would allow wet sweeping, HEPA filtered vacuuming or other methods that would minimize the employee’s exposure.   The use of compressed air to clean clothing and/or surfaces would not be allowed unless the compressed air is used with a ventilation system that captures the dust cloud or no alternative method is feasible.

Our next post will address the medical surveillance and training requirements.


[i] OSHA’s Final Rule to Protect Workers from Exposure to Respirable Crystalline Silica: