Health professionals have known for many years that breathing crystalline silica poses significant health risks for workers. In fact, over 40 years ago, NIOSH (National Institute for Occupational Safety & Health) recommended the same exact permissible exposure limit that OSHA has recently imposed.

There is sound science indicating that breathing in silica particles is linked to lung cancer, silicosis, Chronic Obstructive Disease (COPD), and illnesses of the kidneys. Unfortunately, some cases have occurred while employers were observing previous OSHA exposure limits. Most of us might murmur about the unfairness or at least the unfavorableness of regulations in general, but one would be hard pressed to contest the fact of historic over-exposures given the available data.

Note to the Reader

The discussion in this article assumes that the reader:

  • Understands basic employee respiratory protection protocols
  • Is not adopting Table 1’s protocols
  • Is primarily interested in developing a reasonable and sustainable program that complies with the current requirements.

This discussion is not intended to elaborate on medical clearances, respirators, or ancillary requirements that are triggered once over-exposure is validated.


In its most fundamental form, the 2017 silica rule asks employers to either use pre-approved methods and protections for certain common tasks or conduct regular testing to validate that no over-exposure exists.

Most of the objections to the rule that we hear are about OSHA halving the permissible exposure limit (PEL) to 50 micrograms of respirable crystalline silica per cubic meter of air. The real issue, however, is that at the new Action Level of 25 ug/m3, employers are required to take specific actions.

Those who argue that compliance with the new federal silica standard is unobtainable, costly, and disruptive are missing an opportunity to make improvements in workplace safety without an unreasonable amount of effort for employers.

Since the early 1990’s, OSHA began using performance-based standards to address over-regulation concerns and to allow employers the ability to craft workplace-specific compliance solutions. Custom performance-based solutions are still allowable under the new standard if proper atmospheric testing is conducted to verify effectiveness of non-authorized controls or under-exposure.

Water Water Water

As with many new mandates, the remedy is less likely to be a complete rewrite of existing practices than a fine-tuning that should have been done in the first place.

Common solutions like applying water at the source work to reduce airborne concentrations to acceptable levels in more applications than is initially apparent. In most cases, they can be used instead of purchasing elaborate technologies. OSHA, furthermore, crafted the new silica rule to encourage its use.

Vacuum-Based Technology

Engineering control requirements, such as vacuum technologies, have needlessly alarmed many in affected industries.

While some applications will require more advanced equipment, it does not appear that most construction exposures will warrant such complex approaches. When companies cannot use water to control the generation of airborne silica dust, ordinary shop vacuums can be effective if they are properly equipped and handled. Atmospheric testing indicates that using HEPA filters and pre-filtering on commercially available shop-type vacuums is extremely effective for removing airborne crystalline silica to levels significantly below the new PEL, and in many cases the Action Level. This is accomplished at the source of generation while maintaining acceptable production levels.

While care, wetting, and precautions must be adhered to when changing filters or emptying bags, the common ShopVactm has proven to be a workable and low-cost solution in a majority of common construction applications.

It should be noted that these precautions are often required with even the most sophisticated dust control systems. Our results suggest that compliance costs and unproductive manpower estimates may have been grossly overstated.

Alternate Control Methods: Disregarding Table 1

For tasks not listed, control methods not adhered to, or when employers do not properly implement effective engineering controls or practices listed in Table 1, there are several methods available that offer compliance, which will likely be sufficient for many situations.

First, remember that employers must ensure that workers are not exposed to greater than the PEL of 50 ug/m3, for an 8-hr TWA. This is verified through valid testing. Since these tests are relatively inexpensive and will serve to establish future PPE requirements, we recommend initial and scheduled verification testing in accordance with 1926.1153 (d)(2)(iii)(B-E) for each task and employee type that deviates from Table 1. These tests, if in line with acceptable exposure levels and performed correctly, will usually satisfy the standard’s “Exposure Assessment” as well as the “Performance Option” and “Scheduled Monitoring” requirements for Table 1 deviation.

When initial monitoring results at the breathing zone are less than 25 ug/m3, the employer may discontinue monitoring until conditions or exposure scenarios change. Note that this option is only valid for the distinct exposures that were tested for and is not applicable to similar work or exposures.

Where initial monitoring indicates that employees are exposed to concentrations above the action level of 25 ug/m3, but below the Permissible Exposure Level of 50ug/m3, the employer must repeat the monitoring every six months to validate the acceptable exposure levels. If a monitoring result that is below the Action Level is achieved, testing must re-occur, at least a week apart, until two consecutive acceptable levels are obtained, to suspend monitoring. Again, these options are only valid for exact exposures that are tested for, and are not applicable to similar work or exposures. In this scenario, we recommend offering N-95 dust masks or half-face HEPA respirators to workers for voluntary use in accordance with the company’s respiratory protection program.

While OSHA offers employers options for addressing test results above the Permissible Exposure Limit of 50 ug/m3, we do not recommend deviating from the Table 1 protocols in those circumstances. In the event of a non-Table 1, listed task, initial, scheduled, and reassessment monitoring, compliant with (d)(2)(iii)(E) of the standard, must be completed once company-specific engineering controls are implemented.

Since respiratory protection is an integral part of silica exposure mitigation, the reader should be mindful that additional respiratory program requirements will likely become obligatory under most any silica compliance scenario. If workers are likely to use respirators for silica protection for more than 30 days per year, the company must also offer enhanced medical clearances.

When developing a workable system for complying to Table 1, we find it typically much more operationally efficient and sustainable to disregard the minimum task time-limits in the standard and adhere to the maximum exposure criteria requirements. In this way, companies avoid the need to track affected task times, provide more protection for the lesser exposures, and minimize non-productive man hours that would be expended on time-tracking and respiratory compliance. When complications with task time-tracking become clear, most companies agree that it is much easier and less costly to simply apply the higher threshold for PPE protection across the board.


While the silica standard is generating a lot of attention, the main effect will be the expansion of some companies’ respirator and atmospheric testing programs. In the event that testing reveals exposure levels of less than 25 ug/m3, only periodic monitoring is required.

We are of the opinion that all but the most extreme exposures can be brought to below the action level with minimal effort. Companies who do not wish to follow Table 1 can, with a scheduled monitoring program and possibly some minor engineering controls, keep silica level below the new permissible exposure limit.

Click here to register for the Silica Rules: Maintaining Compliance No Matter the Task! webinar, presented by Bart Briggs, founder of Safety Plus Inc.