Any operation that blasts a silica-containing abrasive, or blasts a surface that contains silica, works under OSHA's respirable crystalline silica rule. The rule caps worker exposure at 50 micrograms of respirable crystalline silica per cubic meter of air over an 8-hour day, and it requires the operation to measure exposures, control them, protect workers with respirators, write a plan, and offer medical exams. The two standards are 29 CFR 1926.1153 for construction and 29 CFR 1910.1053 for general industry and maritime.
The Rule Caps Exposure at 50 Micrograms, With an Action Level at 25
The core number is the permissible exposure limit. **No worker may be exposed to more than 50 micrograms per cubic meter as an 8-hour average, and exposure at or above the action level of 25 micrograms triggers air monitoring and medical surveillance.** The action level exists so that an operation approaching the limit acts before it crosses it, rather than after.
Silica is measured because it is the dust that causes silicosis and lung disease. The rule targets the crystalline form specifically, which is why the medium you blast with matters so much, a point covered in Silica-Free Media Options for Safer Blasting.
Blasting Is Not on the Shortcut Table, So You Measure and Control
Construction has a shortcut called Table 1 that pairs common tasks with set controls, but abrasive blasting is deliberately left off Table 1, so a blasting operation cannot use the shortcut and must instead assess exposures and control them to the permissible limit on its own. That is the alternative exposure control method, and it means air sampling rather than a lookup.
Assessing exposure means sampling the air during the actual blasting work, or relying on objective data that reliably represents it, and repeating that assessment when the media, the enclosure, or the task changes. OSHA is direct that engineering controls alone rarely bring silica-abrasive blasting under the limit, so an operation blasting silica-containing media almost always combines ventilation with respiratory protection to comply. Blasting operations also fall under related standards, including 29 CFR 1926.57 for ventilation.
## Controls Follow a Hierarchy Before Respirators
The rule expects the operation to cut the dust at the source first and reach for respirators last. Ventilation and containment come first, work practices next, and respiratory protection covers whatever the first two cannot.
- Engineering controls: enclosure, exhaust ventilation, and media reclaim that keep dust out of the air, discussed in [Dust Collectors and Silica Compliance](#dust-collectors-silica)
- Work practices: procedures that limit how much dust is generated and how far it spreads
- Respiratory protection: supplied-air or other respirators for the exposure that controls do not remove
A Written Exposure Control Plan Names a Competent Person
The operation puts its approach in writing. The written exposure control plan describes the tasks that create silica exposure, the controls in place for each, and the housekeeping that keeps dust down. In construction, the employer designates a competent person to carry out the plan and inspect the job regularly, and the plan is reviewed at least once a year and updated as the work changes.
Medical Surveillance Is Offered at No Cost
Workers carrying the most exposure are entitled to medical monitoring. Any employee required to wear a respirator for this work, or exposed above the limits, for 30 or more days a year must be offered medical surveillance at no cost. The exams include a work and medical history, a physical, a chest x-ray, a pulmonary function test, and an initial test for latent tuberculosis, repeated on a set schedule so that early lung changes are caught.
Training, Housekeeping, and Records Complete Compliance
Three more obligations round out the rule. Workers get hazard training so they understand the silica risk and the controls. Housekeeping bars dry sweeping and compressed-air cleaning where a safer method is available, because both throw settled dust back into the air. And the operation keeps records of its exposure measurements and medical exams for the periods the standard sets.
The First Control Is the Media You Choose
Every requirement above gets easier when the abrasive is not the source of the hazard. Blasting a silica-free medium removes the crystalline silica from the media side of the equation, which is why moving off sand is the first and cheapest compliance step rather than the last. It does not remove silica that comes from the substrate being blasted, so controls still apply, but it takes the biggest source off the table. Which silica-free or low-silica media suit your work is covered in Silica-Free Media Options for Safer Blasting, and the media itself is stocked and ready on the Gulf Coast.