Search the LHSFNA website
Published: December, 2018; Vol 15, Num 6


Top 10 Contractor Questions and Answers on Complying with the Silica Standard

In October, the LHSFNA hosted its fourth silica webinar for LIUNA signatory contractors and other LIUNA affiliates. Fund staff were joined by David O’Connor from OSHA’s Directorate of Standards and Guidance and Michael Gorman with DeWalt tools. David, Michael and the LHSFNAs OSH Division fielded many direct questions from contractors during the webinar, which is now available for viewing in the Fund’s online Webinar Archive at

If you have questions about silica compliance, we highly recommend you take the time to watch the entire webinar. In the meantime, we’ve collected answers to ten of the most commonly asked questions below. If you have additional questions, please contact the Fund’s OSH Division at 202-628-5465.

1. Do employers have to consider exposures from other contractors when determining if their employees will remain below the silica standard’s action level (AL)?

Yes. For example, if a subcontractor has employees in an area where workers from a different subcontractor are generating silica dust, those exposures would fall under the standard if they exceed the AL. Employers should work with the general contractor to ensure their employees aren’t exposed above the AL; the use of a competent person may be particularly helpful during these operations.

2. Does the silica competent person have to be on site at all times?

No. The standard only requires the competent person to make “frequent and regular inspections” but does not define these terms in greater detail. Inspections must be regular and frequent enough to ensure that the site-specific written exposure control plan is being carried out, that engineering controls are being implemented and that any compliance issues are being corrected promptly.

3. For some tasks on Table 1, respirator requirements vary depending on task duration (i.e., more or less than four hours). Do contractors have to track the exact amount of time workers spend on a silica-generating task?

No. OSHA does not expect employers to track every minute of time spent performing a task; the expectation is that the employer will make a reasonable assessment of how long the task will take to perform before the job begins, then base the potential need for respirators on this assessment. In the event the task takes longer to perform, OSHA expects employers to provide additional protection as soon as they become aware that the task will exceed the threshold.

4. Does the standard require employers to count any time spent using a respirator as one day of use toward the 30 day trigger for medical surveillance? What about voluntary respirator use – does that count toward the 30 day trigger?

If the silica standard requires an employee to use a respirator at any point during the day, that counts as one day, whether that respirator is worn for five minutes or eight hours. However, keep in mind that tasks with a very short duration (e.g., drilling a few holes over an entire shift) are not likely to require respirator use, since exposures are likely to be below the AL over an eight hour time-weighted average (TWA). Some tasks, however, such as abrasive blasting, generate such high exposures that they are likely to trigger the AL.

In the case of voluntary respirator use, if the use is voluntary or required by another standard, it does not count towards the silica standard’s 30 day trigger for medical surveillance.

5. Can employers rely on a worker’s verbal statement that they have undergone medical surveillance and can safely wear a respirator?

No, workers claiming to have undergone medical surveillance must show documentation to that effect. If they no longer have the report, the worker should be able to contact the examining physician to obtain a copy of that written medical opinion.

6. Can employers choose the physician who provides medical surveillance? What is the difference between the report given to the employer and the employee?

An employer can choose the physician who provides the exam. However, that doesn’t change the information they receive as a result of that exam. Under the standard, the employer only receives a written medical opinion, which states that the employee has had the exam, whether there is a recommendation to see a specialist and whether there are any restrictions on respirator use. The employee receives a more detailed report about the results of the exam; the only way the employer will see this report is if the employee chooses to share it.

7. Can employers use a water bucket with a hole in it as an alternative control method?

It depends. While not in compliance with Table 1, it could be in compliance under the alternative compliance options. It really comes down to an assessment of each task. If an assessment supports that exposures are not over the permissible exposure limit (PEL) and that engineering and work practice controls are being used to the extent feasible, it would be compliant.

8. Can workers perform dry brushing, sweeping or use compressed air for cleaning if exposures do not exceed the AL?

Yes. Because the standard does not apply below the AL, none of the standard’s housekeeping requirements would be in effect. The standard’s housekeeping requirements are in place to prevent overexposure, so if an assessment determines exposures will be below the AL, employees can perform those tasks.

9. What are the requirements for dumping dust collected in tools or captured at the point of dust generation?

OSHA views the cleaning of filters and disposing of dust collected in integrated tools as being part of fully and properly following the manufacturer specifications mentioned in Table 1. When not doing tasks on Table 1, such as when an employee is performing housekeeping (e.g., assigned to clean all of the equipment on a large site), that would require an exposure assessment to ensure the worker is not overexposed.

10. Assuming exposures are over the AL but under PEL, is it okay for employers to give workers the option to wear respirators or other personal protective equipment?

That’s at the discretion of the employer. However, it’s worth noting that employees are still at significant risk from silica exposure below the PEL, but OSHA was precluded from mandating a lower PEL due to economic feasibility. So for employers who want to offer the greatest level of protection to employees, allowing voluntary respirator use even when exposures are below the PEL would be a reasonable thing to do.

The Fund has many publications that can provide additional information about complying with OSHA’s silica standard and protecting worker health. Those publications include the Silica and Table 1: A Field Guide to Compliance pamphlet, the Silica Rule Compliance Flowchart and the Preventing Exposure to Respirable Silica Dust toolbox talk. To order these or other publications, go to and click on Publications.

[Nick Fox]