Still Have Questions About the Silica Construction Rule? OSHA Has Answers.


The updated U.S. OSHA silica construction standard has been in enforcement for over two years. Do you need to learn more in order to help achieve compliance with this silica standard? Here are some selected, informative answers excerpted directly from a large list of Frequently Asked Questions provided by OSHA to help you figure out what changes you may need to make to your safety program protocols and personal protective equipment (PPE) selection in order to help avoid injuries, violations and penalties.

Does the Standard Cover Employees Who Perform Silica-Generating Tasks for Only 15 Minutes or Less a Day?

Yes. The current updated standard does not include a specific exemption for tasks with only short-term exposures, which includes exposures for 15 minutes a day or less.

“However, in many cases, employees who perform construction tasks for very short periods of time, in isolation from activities that generate significant exposures to silica (e.g., some tasks listed on Table 1, abrasive blasting), will be exposed below the action level (AL) of 25 μg/m3 as an 8-hour time-weighted-average (TWA) under any foreseeable conditions. Short-term silica exposures must be very high in order for those exposures to reach or exceed this action level limit of 25 μg/m3 as an 8-hour TWA; for example, if an employee is exposed for only 15 minutes, his or her exposure would have to be higher than 800 μg/m3 for that 15-minute period before the 8-hour TWA exposure would be at or above 25 μg/m3. See 81 Fed. Reg. at 16706. Some examples of tasks that could generate very high short-term exposures include abrasive blasting and grinding, which are typically associated with high levels of visible dust.”

“OSHA has identified carpenters, plumbers, and electricians as types of workers who may perform tasks (e.g., drilling with a handheld drill) involving occasional, brief exposures to silica that are incidental to their primary work. See 81 Fed. Reg. at 16706. Provided that these employees perform these tasks in isolation from activities that generate significant exposures to silica, and perform them for no more than 15 minutes throughout the work day, their exposures will usually fall below the AL of 25 μg/m3 as an 8-hour TWA under all foreseeable conditions; when that is the case, these employees will not be covered by the standard.”[i]

If the task will not be completed in isolation or may exceed 15 minutes, review the protocols for evaluating exposure through exposure assessments, proper implementation of Table 1, and /or personal breathing zone sampling methods to determine what workers are at risk of meeting this AL threshold and make adjustments to your safety procedures, such as your written exposure control plan (WECP), as needed. Download our handy checklist to help you take steps to achieve compliance with this construction silica standard.

Has OSHA Identified Specific Tasks that are Likely to be Outside the Scope of the Standard Because They Typically Generate Exposures Below the Action Limit Under All Foreseeable Conditions?

“Yes. When the following tasks are performed in isolation from other silica-generating tasks, they typically do not generate silica at or above the AL of 25 µg/m3 as an 8-hour TWA under any foreseeable conditions: mixing small amounts of mortar; mixing small amounts of concrete; mixing bagged, silica-free drywall compound; mixing bagged exterior insulation finishing system (EIFS) base and finish coat; removing concrete formwork; using block or tile splitters; and using manual (i.e., non-powered) chisels, shears, and utility knives.”

“In addition, tasks where employees are working with silica-containing products that are, and are intended to be, handled while wet, are likely to generate exposures below the AL under any foreseeable conditions (examples include finishing and hand wiping block walls to remove excess wet mortar, pouring concrete, and grouting floor and wall tiles).”[ii]

Many of the Entries on Table 1 Require Employers to Operate and Maintain Tools in Accordance with Manufacturer’s Instructions to Minimize Dust Emissions. If an Employer is Following Table 1, and Employees are Performing One of these Tasks, Does the Silica Standard Require the Employer to Follow Every Element of the Tool Manufacturer’s Instructions?

“No, the silica standard requires employers to follow manufacturer instructions that are related to dust control. In determining which instructions might relate to dust control, employers should consider whether the failure to follow the particular instruction would increase employee exposure to silica.”[iii] For a list of examples of manufacturer instructions for minimizing dust emissions that employers may want to consult, please see #9 of complete OSHA’s FAQ and 29 C.F.R. § 1926.1153(c)(1)(i)-(vii), (x)-(xiii), (xvi).

In addition to the FAQ’s, OSHA issued interim guidance for inspectors on October 19, 2017, which states, “where the construction employer is fully and properly implementing the engineering controls, work practices, and respiratory protections specified in Table 1 for each employee engaged in listed tasks, there is no requirement for the [OSHA] CSHO to collect personal air samples for those tasks.”[iv]

What Constitutes an Enclosed Area for Purposes of Compliance with Table 1?

“Some of the entries on Table 1, as well as paragraph (c)(2)(i), include specific requirements for tasks performed ‘indoors or in enclosed areas.’ This term refers to any areas where, without the assistance of forced ventilation, the dispersal of airborne dust can be impeded and concentrations can build up. For example, a work area with only a roof that does not affect the dispersal of dust would not be considered enclosed; however, an open-top structure with three walls and limited air movement could be considered enclosed. Parking garages, pits, trenches, and empty swimming pools may qualify as enclosed areas.”[v]

For a Few Tasks on Table 1, Respirator Requirements Vary Based on Task Duration, i.e., Whether the Task is Performed for “Less Than or Equal to Four Hours/Shift” or “Greater than Four Hours/Shift.” Does the Employer Have to Track the Exact Amount of Time that Employees are Performing a Job Throughout a Shift to be in Compliance with Table 1?

“No. Before the task is performed, the employer must make a good-faith judgment about whether the task will take more than four hours. This judgment should be based on previous experience and other available information.”

“If the employer anticipates that an employee will be engaged in a task for more than four hours, the employer must provide the employee, at the beginning of the shift, the respiratory protection required in the ‘greater than four hours/shift’ column on Table 1. If, in contrast, the employer anticipates that an employee will be engaged in a task for four hours or less, the employer needs to provide respiratory protection in accordance with the ‘less than or equal to four hours/shift’ column (which in many cases does not call for the use of any respiratory protection).”

“However, if the employer experiences unforeseen difficulties or other circumstances that are expected to extend the task duration beyond four hours, the employer must provide the respiratory protection required in the ‘greater than four hours/shift’ column as soon as it becomes evident that the duration of the task may exceed the 4-hour threshold. (In that situation, the 4-hour mark is still measured from the beginning of the task, not from the time the expected duration of the task changes.)”[vi]

For an example of how this may be determined, please see #14 of the complete OSHA Silica FAQ.

Also, “[i]f Table 1 requires respiratory protection when the anticipated task duration exceeds four hours, employees engaged in the task must wear the respirator during the entire period of time they are performing the task, not just the period of time that exceeds four hours” and “until the tool/equipment is no longer in use.”[vii]

If Employees are Performing Silica-Generating Tasks on a Particular Floor of a Construction Site, Does the Employer Need to Restrict Access Such that No Other Employees Can Enter the Floor Where the Silica-Generating Tasks are Occurring?

“No. OSHA does not intend for the standard to prohibit all employees from entering entire areas of a construction site simply because employees in those areas are performing some work involving the generation of silica. The standard requires employers to restrict access to work areas only in certain situations, e.g., ‘where respirator use is required under Table 1 or an exposure assessment reveals that exposures are in excess of the PEL.’ [81 Fed. Reg. at 16803]

Furthermore, the competent person, who is designated by the employer to implement the written exposure control plan under paragraph (g)(4) of the standard, could identify additional situations where limiting access is necessary. [See 81 Fed. Reg. at 16803] Also, the rule calls only for minimizing the number of employees in the relevant work areas. The standard does not preclude employees from entering work areas where silica-generating tasks are occurring when it is necessary for them to do so. However, the employer must comply with the standard (including Table 1 or alternative exposure control methods) as it applies to any employees entering these areas.”[viii]

Does the Standard Require Employers to Count Any Day During Which an Employee is Required to Use a Respirator, for Any Amount of Time, as a Day of Respirator Use for Purposes of Applying the 30-Day Trigger for Medical Surveillance?

“Yes. If an employee is required by the standard to use a respirator at any time during a given day, regardless of the duration of the respirator use, that day counts as one day toward the 30-day threshold for medical surveillance. Thus, a ‘day’ of respirator use for purposes of the 30-day threshold does not mean a full day of respirator use.”[ix]

Does the Standard Require Employees to Participate in Medical Surveillance?

“No, although the standard requires employers to make medical surveillance available to qualifying employees, the standard does not require qualifying employees to participate in medical surveillance. However, the employer must offer the examination fairly and in good faith, at no cost to employees, and at a reasonable time and place, and must make another examination available if the employee requests it or, at a minimum, the next time an examination is due (i.e., within three years). See 29 C.F.R. § 1926.1153(h). In addition, the standard requires employers to train employees on the purpose of the medical surveillance program. See 29 C.F.R. § 1926.1153(i)(2)(i)(F). If an employer wishes to document an employee’s decision to decline a medical examination, the employer could ask the employee to sign a statement affirming that he or she was offered the benefits and declined to participate.

Note that the medical examination under the silica standard is different than the medical evaluations required under the respiratory protection standard. If an employee declines a medical evaluation under the respiratory protection standard, then the employer may not assign him or her a task requiring respirator use.”[x]

Medical exams must be made available to any worker who uses a respirator for 30 or more days a year (and any partial day is considered one day) according to 29 C.F.R. § 1926.1153.


Employers who are affected by this silica standard are encouraged to review the full FAQ provided by OSHA to help improve their understanding and minimize risk of injuries to workers. Please also evaluate the exposure assessments, control methods, exposure control plans and hazard communications you currently have in place to help protect workers and what changes you may need to make to help avoid regulatory violations, fines and most importantly, injuries to your workforce. We also encourage you to download this handy infographic and contact us today for help selecting applicable PPE and training to help achieve proper compliance.

[i] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question #2
[ii] Frequently Asked Questions (“FAQs”) for the Construction Industry: #1
[iii] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question #9
[iv] Interim Enforcement Guidance for the Respirable Crystalline Silica in Construction Standard, 29 CFR 1926.1153 (October 19, 2017) Section: Inspection Guidance: For Employers Following Table 1 [paragraph (c)]
[v] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question #13
[vi] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question #14
[vii] Interim Enforcement Guidance for the Respirable Crystalline Silica in Construction Standard, 29 CFR 1926.1153 (October 19, 2017) Section: Inspection Guidance: Respiratory Protection [paragraph (e)]
[viii] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question 34
[ix] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question #39
[x] Frequently Asked Questions (“FAQs”) for the Construction Industry: Question #43