| Respirable crystalline silica PEL |
Keeps the operator outside the blast zone during programmed cycles, reducing the need for direct manual blasting. |
OSHA’s permissible exposure limit is 50 µg/m³ as an 8-hour time-weighted average for respirable crystalline silica. |
Use personal or area air monitoring where required by the applicable OSHA standard and exposure assessment. |
| Action level |
Consistent automated loading, blasting, and unloading can help limit task variability and uncontrolled operator contact. |
OSHA’s action level is 25 µg/m³ as an 8-hour time-weighted average. |
Review exposure-monitoring results and reassess whenever materials, equipment, or work practices change. |
| Containment of abrasive dust |
A sealed cabinet or enclosure can contain abrasive and generated dust while the machine is operating. |
The enclosure should prevent visible dust release during normal operation and remain properly maintained. |
Inspect door seals, gloves, viewing windows, duct connections, and access points for leakage or damage. |
| Local exhaust ventilation |
Integrated or connected dust collection captures airborne particulate at the enclosure before it reaches the operator’s breathing zone. |
Ventilation is an engineering control; it must be appropriately designed, operated, and maintained for the process. |
Check airflow, pressure indicators, filters, collection containers, and scheduled maintenance records. |
| Abrasive selection |
The system can be configured for abrasives that do not contain crystalline silica, where suitable for the workpiece and finish requirements. |
Using a non-silica abrasive may reduce silica hazards, but other dust and chemical hazards can remain. |
Review the abrasive safety data sheet, composition, particle-size information, and process-specific hazard assessment. |
| Wet blasting option |
Introducing water at the point of dust generation can suppress airborne dust when compatible with the equipment and product. |
Wet methods are recognized engineering controls for reducing respirable dust, but they do not eliminate the need for evaluation. |
Confirm adequate water delivery, drainage, corrosion control, housekeeping, and monitoring of residual airborne dust. |
| Operator proximity and cycle control |
Programmable cycles reduce the time workers spend manually aiming blast nozzles or opening an active blast area. |
Automation supports the hierarchy of controls by reducing exposure at the source, but it is not proof of compliance by itself. |
Observe normal and abnormal operations, including loading, unloading, maintenance, and cleanup activities. |
| Housekeeping and secondary dust |
Controlled media recovery can reduce dust accumulation compared with uncontrolled sweeping or compressed-air cleaning. |
Dry sweeping and compressed air should not be used where they could contribute to silica exposure unless specific conditions allow them under OSHA requirements. |
Use suitable vacuuming or wet-cleaning procedures and inspect floors, ledges, equipment surfaces, and collection areas. |
| Respiratory protection |
Effective containment and ventilation may reduce reliance on respirators, depending on measured exposures and the applicable standard. |
Respirators are generally used when engineering and work-practice controls cannot adequately limit exposure or during certain maintenance and emergency tasks. |
Base decisions on exposure assessment and maintain a compliant respiratory-protection program when respirators are required. |
| Training and records |
Standardized machine controls and documented procedures can make training, inspections, and corrective actions more repeatable. |
OSHA silica requirements include employee information and training, exposure-control practices, and recordkeeping provisions where applicable. |
Maintain training records, exposure assessments, medical records where required, equipment inspections, and corrective-action logs. |
