Respirable Crystalline Silica is the subject of two OSHA standards, 29 CFR 1910.1053 for general industry and maritime and 29 CFR 1926.1153 for construction, that limit how much fine silica dust workers may breathe. They protect workers who cut, grind, drill, crush or blast materials such as concrete, stone, brick, sand and engineered stone.
Inhaling respirable crystalline silica can cause silicosis, lung cancer, chronic obstructive pulmonary disease and kidney disease. The standards require controls, a written plan, medical exams, training and records.
What Is the OSHA Silica Standard?
OSHA published the current silica rule on March 25, 2016, creating two parallel standards in Subpart Z of Parts 1910 and 1926. Both set the same core numbers:
- Permissible exposure limit (PEL): 50 micrograms per cubic meter of air (µg/m³), averaged over an 8-hour shift.
- Action level: 25 µg/m³ as an 8-hour time-weighted average. Exposure at or above this level triggers assessment and, in general industry, medical surveillance.
Respirable means the particles are small enough to reach deep into the lungs.
The construction standard took effect June 23, 2016, with most obligations beginning June 23, 2017. In general industry, most obligations began June 23, 2018, and the medical surveillance trigger dropped to the action level on June 23, 2020. Hydraulic fracturing operations had until June 23, 2021 to put engineering controls in place.
Who Must Comply?
General industry and maritime (1910.1053)
The general industry standard covers occupational exposures in settings such as foundries, concrete products and brick manufacturing, glass, stone and countertop fabrication, abrasive blasting and hydraulic fracturing. It does not apply to construction, to agricultural operations, to exposures from processing sorptive clays, or where objective data show exposures will stay below the action level under any foreseeable conditions. Employers may follow the construction standard for tasks that are indistinguishable from construction tasks listed in Table 1, if those tasks are not done regularly in the same environment.
Construction (1926.1153)
The construction standard covers all occupational exposures in construction work unless exposure will remain below 25 µg/m³ as an 8-hour average under any foreseeable conditions. Common tasks include sawing concrete, jackhammering, drilling masonry and grinding mortar.
Host employers and staffing agencies share responsibility for protecting temporary workers. In states with OSHA-approved state plans, state rules apply and must be at least as effective as the federal standards.
Key Requirements
Table 1 in construction
The construction standard offers a compliance path that general industry does not. Table 1 in 1926.1153(c) lists common equipment and tasks and, for each, the engineering controls, work practices and respirator required. An employer that fully and properly implements the Table 1 controls for a task does not need to measure exposure for that task.
For example, for handheld power saws Table 1 calls for a saw with an integrated water delivery system that continuously feeds water to the blade. Outdoors, no respirator is required for 4 hours or less per shift, and an APF 10 respirator is required for more than 4 hours. Indoors or in enclosed areas, an APF 10 respirator is required regardless of duration. Tasks not on Table 1, or where its controls are not fully followed, must use the alternative method in 1926.1153(d): assess exposure and keep it at or below the PEL.
Exposure assessment
Where exposure is or may reasonably be expected to be at or above the action level, employers must assess it under either option:
- Performance option. Any combination of air monitoring and objective data that accurately characterizes exposure.
- Scheduled monitoring option. Initial personal breathing zone sampling. If results are below the action level, monitoring may stop. If at or above the action level but at or below the PEL, repeat within 6 months. If above the PEL, repeat within 3 months. Monitoring can stop after two consecutive results, taken at least 7 days apart, fall below the action level.
Reassess whenever changes in production, process, controls, personnel or work practices could raise exposures. Employees must be notified of results within 15 working days after completing an exposure assessment in general industry, and within 5 working days after completing it in construction.
Methods of compliance
Engineering and work practice controls, such as wet methods, local exhaust ventilation and enclosed cabs, are the primary means of meeting the PEL, consistent with the hierarchy of controls. Respirators supplement them only where controls are not feasible or not sufficient, and require a program meeting the Respiratory Protection Standard.
Written exposure control plan
Both standards require a written plan describing tasks that involve exposure, the controls, work practices and respiratory protection used for each, and housekeeping measures. The construction plan must also describe procedures to restrict access to work areas where needed. The plan must be reviewed at least annually and updated as necessary. In construction, the employer must designate a competent person to make frequent and regular inspections of job sites, materials and equipment to implement the plan.
Regulated areas in general industry
General industry employers must establish a regulated area wherever exposure is or can reasonably be expected to be above the PEL, post warning signs at entrances, limit access to authorized people and require respirators inside.
Housekeeping
Dry sweeping and dry brushing are not allowed where they could contribute to exposure, unless wet sweeping, HEPA-filtered vacuuming or other low-exposure methods are not feasible. Compressed air may not be used to clean clothing or surfaces unless it is paired with ventilation that captures the dust cloud or no alternative is feasible.
Medical Surveillance, Training and Records
Medical exams
The trigger differs between the standards. In general industry, employers must offer exams at no cost to employees exposed at or above the action level for 30 or more days a year. In construction, the trigger is being required to wear a respirator under the standard for 30 or more days a year.
The initial exam must be offered within 30 days of initial assignment, unless the employee had a qualifying exam in the last three years. It includes a medical and work history, a physical exam focused on the respiratory system, a chest X-ray read by a NIOSH-certified B Reader, a pulmonary function test, latent tuberculosis testing and any other tests the licensed health care professional considers appropriate. Periodic exams follow at least every three years. The employee receives a written medical report and the employer receives a limited written opinion, each within 30 days of the exam.
Training
Silica must be covered in the employer's hazard communication program. Each covered employee must be able to demonstrate knowledge of the health hazards, tasks that could cause exposure, protective measures, the contents of the standard, the purpose of medical surveillance and, in construction, the identity of the competent person.
Recordkeeping
Employers must keep records of air monitoring, objective data relied on and medical surveillance. These records are maintained and made available under OSHA's exposure and medical records rule, which generally means at least 30 years for exposure records and employment plus 30 years for medical records.
Common Violations and Penalties
- Partial Table 1 controls. Using a wet saw with too little water, or skipping the required respirator on long tasks, which takes the task out of Table 1.
- No exposure assessment. Performing non-Table 1 tasks, or general industry work, without monitoring or objective data.
- Missing or stale written plan. No plan, or one not reviewed annually.
- Dry sweeping and compressed air. Cleaning up dust in ways that put it back in the air.
- Medical surveillance gaps. Not tracking who reached 30 days a year and not offering exams on time.
OSHA's maximum civil penalties for penalties assessed after January 15, 2026 are $16,550 per serious violation and $165,514 per willful or repeated violation. Check OSHA's penalties page for current figures.
How to Comply: Step by Step
- Determine which standard applies. Construction follows 1926.1153; other work follows 1910.1053.
- List silica tasks. Identify every task that cuts, grinds, drills, crushes or blasts silica-containing material.
- Choose a compliance path. In construction, match tasks to Table 1 where possible. Otherwise assess exposures using monitoring or objective data.
- Install controls. Use water delivery, dust collection or ventilation, and maintain it.
- Write the exposure control plan. Cover tasks, controls, housekeeping and access restrictions, and review it at least annually.
- Run a respiratory protection program. Include fit testing, medical evaluation and training wherever respirators are required.
- Track days and offer exams. Count each employee's days of exposure or respirator use and offer medical surveillance at 30 days.
- Keep records. Document training, assessments and medical opinions.
How SMS360 Helps
SMS360's Risk Assessment module helps teams document each silica-generating task, the controls selected and the residual risk, and keep those assessments current as equipment and processes change. Assessments can be completed in the field on mobile devices, linked to corrective actions and reviewed alongside training records and inspection checklists.
Frequently Asked Questions
What is the OSHA PEL for respirable crystalline silica?
The permissible exposure limit is 50 µg/m³ averaged over an 8-hour shift, in both general industry and construction. The action level is 25 µg/m³. Exposures at or above the action level trigger assessment duties and, in general industry, medical surveillance for employees exposed 30 or more days a year.
Do I need air monitoring if I follow Table 1?
No. In construction, an employer that fully and properly implements the Table 1 controls, work practices and respirators for a listed task is not required to assess exposure for that task. If a task is not listed or the controls are not fully followed, the employer must assess exposure and keep it at or below the PEL.
How often are silica medical exams required?
An initial exam must be offered within 30 days of initial assignment, and periodic exams at least every three years, or more often if the health care professional recommends. Exams are offered at no cost to employees who meet the 30-day trigger in their standard.
Does the silica standard apply to engineered stone countertops?
Yes. Cutting, grinding and polishing engineered stone can release high levels of respirable silica. Fabrication shops are generally covered by the general industry standard, while installation work at a job site may fall under the construction standard.
