OSHA's Crystalline Silica Rule: What Construction and General Industry Employers Must Know

Silica is the second-most-common mineral in the earth’s crust. It’s also one of the most common causes of occupational lung disease in the United States. Cutting, grinding, drilling, or jackhammering materials that contain crystalline silica, such as concrete, masonry, sandstone, rock, and some engineered stone products, releases fine dust particles that workers inhale. Small enough to reach deep lung tissue, those particles cause silicosis, an incurable and sometimes fatal scarring of the lungs. Long-term exposure is also linked to lung cancer and kidney disease.

OSHA finalized its crystalline silica rule in March 2016. Construction employers had until June 2018 to comply fully. General industry had the same effective date for most provisions. The rule replaced silica exposure limits that had been in place since 1971, and those old limits were not protective by modern standards.

Two Standards, One Goal

OSHA published two separate silica standards under the same rulemaking:

29 CFR 1926.1153 covers construction. 29 CFR 1910.1053 covers general industry and maritime operations. Both share the same exposure limits, but they differ in how employers must meet them, and that difference matters a great deal for how you run your compliance program.

The construction standard includes Table 1, a task-based compliance option that lets employers skip exposure monitoring entirely if they follow specified controls for listed tasks. General industry gets no such shortcut. Every general industry employer must conduct exposure assessments to determine where workers stand relative to the limits.

The Exposure Limits

The permissible exposure limit under both standards is 50 micrograms per cubic meter of air (µg/m³), measured as an 8-hour time-weighted average (TWA). The action level is 25 µg/m³, also as an 8-hour TWA.

The old 1971 PEL varied by the percentage of quartz in the dust, but in practice it allowed exposures far higher than 50 µg/m³. OSHA estimated at the time of rulemaking that the new limits would prevent thousands of silicosis deaths and hundreds of lung cancer deaths over the following decade.

Once a worker’s exposure reaches the action level, specific obligations kick in. Once it reaches the PEL, additional requirements apply.

How the Construction Standard Works: Table 1

The construction standard is built around Table 1, which lists 18 specific tasks along with the engineering controls, work practices, and respiratory protection required for each. If your workers perform a listed task using the Table 1 controls correctly, you don’t need to measure airborne silica concentrations. That’s the tradeoff: follow the controls precisely, and you get the monitoring exemption.

Some examples:

Handheld grinders on masonry or concrete require either wet methods or an integrated water delivery system plus a HEPA vacuum, along with a respirator providing an assigned protection factor (APF) of at least 10. That means a half-face air-purifying respirator with N95 or better filtration.

Jackhammers and handheld powered chisels on concrete or rock require wet methods or a HEPA vacuum shroud attachment, plus a respirator with an APF of at least 10.

Walk-behind saws on concrete or masonry require either integrated water delivery or a HEPA vacuum. A respirator is required if the equipment lacks a water delivery system.

Tuck-point grinders require a shroud or enclosure with a HEPA vacuum, plus a respirator with APF of at least 10.

If you deviate from Table 1 for any listed task, or if a task isn’t listed at all, you must monitor air concentrations and apply controls based on measured exposure levels. The deviation triggers the full exposure monitoring pathway.

Exposure Monitoring in Construction and General Industry

When monitoring is required, the results determine which tier of controls and requirements applies.

At or above the action level (25 µg/m³): The employer must monitor every six months, offer medical surveillance every three years, and maintain a written exposure control plan.

At or above the PEL (50 µg/m³): Monitoring frequency increases to quarterly, medical surveillance must be offered annually, and respirator use becomes required to get exposure below the PEL using feasible engineering and administrative controls.

For general industry employers, the starting point is always an exposure assessment. That means either reviewing objective data (e.g., published studies for the specific operation), conducting personal air monitoring using OSHA methods, or using a combination of both. You can’t skip this step.

Written Exposure Control Plan

Every employer covered by the silica rule must have a written exposure control plan when workers may be exposed at or above the action level. OSHA doesn’t mandate a specific format, but the plan must describe the tasks that involve silica exposure, the engineering controls and work practices in use, housekeeping measures, and how the employer will restrict access to high-exposure areas.

The plan isn’t a one-time document. You’re expected to review and update it at least annually and whenever changes in tasks, processes, or controls make the existing plan inaccurate. Keeping it current is not optional. OSHA compliance officers will ask for it during inspections.

For employers following the job hazard analysis process, the silica exposure control plan should integrate naturally with existing hazard documentation. The two documents reinforce each other.

Medical Surveillance Requirements

Medical surveillance is one of the more time-intensive pieces of the silica rule. The basic trigger: a worker must be exposed at or above the action level for 30 or more days per year. Once that threshold is met, the employer must offer medical surveillance.

What the program includes:

An initial examination, then periodic exams based on exposure level. Above the action level, exams every three years. Above the PEL, annually.

Each examination must include a medical and work history with emphasis on respiratory symptoms and smoking history, a physical examination with focus on the respiratory system, pulmonary function testing (spirometry), a chest X-ray reviewed by a NIOSH-certified B Reader, and any additional tests the examining physician recommends.

The physician provides a written medical opinion to the employer stating whether the worker has any detected medical condition that would place them at increased risk from silica exposure. The physician communicates separately and directly with the worker. Employers do not get access to full medical records, only the determination.

OSHA does not require employers to pay for treatment of silicosis or any other diagnosed condition. The medical surveillance requirement is for monitoring and early detection, not treatment.

Housekeeping Requirements

Dry sweeping and dry brushing where these methods could stir up silica dust are prohibited. This applies even in areas where workers aren’t actively cutting or grinding. Accumulated silica dust on floors, shelves, and equipment can become airborne again if disturbed by foot traffic or sweeping.

Permitted methods for cleaning silica-containing dust include wet suppression, vacuuming with HEPA-filtered equipment, and other methods that prevent dust from becoming airborne. This requirement often catches maintenance and custodial workers who aren’t directly involved in cutting operations but still work in dusty environments.

Respiratory Protection Under the Silica Rule

Respirators required by the silica rule must be selected and used in accordance with OSHA’s respiratory protection standard (29 CFR 1910.134). That means a written respiratory protection program, medical evaluation before workers wear tight-fitting respirators, fit testing, and training.

When Table 1 specifies a minimum APF, the employer must select a respirator that meets or exceeds it. An APF of 10 means a half-face air-purifying respirator. An APF of 25 requires a powered air-purifying respirator with a hood or helmet or a supplied-air respirator at appropriate settings. Substituting a lower-rated respirator to save money doesn’t satisfy the standard.

The personal protective equipment guide covers general PPE selection principles, but silica respirator requirements are specific enough that they warrant their own review every time a new task or process is added.

Inspections and Enforcement

OSHA has cited silica violations under both the construction and general industry standards since enforcement began. Common citations involve missing or incomplete written exposure control plans, failure to implement Table 1 controls fully (for example, using water suppression but omitting the required respirator), and failure to offer medical surveillance. Failure to conduct required exposure monitoring in general industry operations has also drawn repeated citations.

Workers who have completed an OSHA 30 construction training course will have received at least introductory exposure to silica hazards, but OSHA 30 is not a substitute for the site-specific training required by the standard. Employers must provide training to all workers who may be exposed at or above the action level, covering the health hazards of silica, the specific tasks that could expose them, and the controls the employer uses.

The Bottom Line for Construction Employers

If your work involves any concrete, masonry, or stone, start with Table 1. Build your written exposure control plan around Table 1 tasks and controls. Implement every control element fully, including respirators at the correct APF, because partial compliance doesn’t get you the monitoring exemption.

Table 1 full compliance is simpler and cheaper to maintain than running a monitoring program. And more importantly, it actually controls the hazard rather than just measuring it.

Sources: OSHA - Crystalline Silica Standard for Construction, 29 CFR 1926.1153 and OSHA - Crystalline Silica Standard for General Industry, 29 CFR 1910.1053