Respirable Crystalline Silica Monitoring
Respirable crystalline silica can be generated when workers cut, grind, drill, crush, abrade, or disturb materials containing silica, including concrete, brick, stone, mortar, sand, tile, and engineered or artificial stone. When silica becomes airborne in respirable particle sizes, it can be inhaled deep into the lungs and may contribute to silicosis, lung cancer, and other serious respiratory disease.
The older shorthand is that respirable dust is a small-particle fraction, often discussed around PM10-sized dust, but regulatory sampling is based on respirable-particle-size selective sampling. In practice, air monitoring is typically performed using calibrated sampling pumps and cyclone samplers placed in the worker breathing zone, followed by laboratory analysis for respirable crystalline silica such as quartz, cristobalite, or tridymite.
Construction and General Industry Standards
Silica exposure is regulated under separate California standards depending on the work setting. Construction work is generally addressed under 8 CCR 1532.3, including Table 1 tasks and exposure assessment requirements. General industry work is addressed under 8 CCR 5204, which includes additional provisions for high-exposure trigger tasks involving artificial stone and certain natural-stone work.
Both standards use an action level of 25 micrograms per cubic meter of air as an 8-hour time-weighted average and a permissible exposure limit of 50 micrograms per cubic meter of air as an 8-hour time-weighted average. In some general-industry/artificial-stone settings, current California requirements include wet methods, regulated areas, scheduled monitoring, housekeeping controls, and powered air-purifying respirator requirements for high-exposure trigger tasks.
When Silica Monitoring May Be Needed
- Construction activities involving cutting, grinding, coring, jackhammering, drilling, or demolition of concrete, stone, tile, masonry, or mortar
- Countertop fabrication or finishing involving natural stone or engineered/artificial stone
- Sand blasting, abrasive blasting, crushing, tunneling, mining, or other high-dust work
- Exposure assessment when Table 1 is not followed or when documentation is needed
- Review of controls such as wet methods, local exhaust ventilation, HEPA-filtered dust collection, isolation, housekeeping, and respiratory protection
Our Crystalline Silica Monitoring Services Include
- Personal breathing-zone air sampling using calibrated pumps and cyclone samplers
- Area air monitoring when useful for project documentation or source evaluation
- Laboratory analysis for respirable crystalline silica using methods such as NIOSH 7500 by X-ray diffraction or NIOSH 7602 by infrared analysis when appropriate
- Comparison of results to applicable Cal/OSHA criteria, including the action level and PEL
- Written exposure assessment reports summarizing observed work, sampling methods, results, and practical observations about exposure controls
- Support for silica exposure control plans, task review, and follow-up monitoring when needed
For compliance-sensitive projects, it is best to discuss the work plan before sampling begins so the monitoring strategy matches the task, standard, and documentation need.
