Compliance · US MSHA
MSHA Respirable Crystalline Silica (30 CFR Part 60)
Occupational: mines (USA)
The US Mine Safety and Health Administration's respirable crystalline silica rule, 30 CFR Part 60 (2024), sets the limit for miners: a permissible exposure limit of 50 µg/m³ for a full shift, calculated as an 8-hour time-weighted average, and an action level of 25 µg/m³ that sets how often exposure must be sampled. It brings mines in line with the limit OSHA set for other industries in 2016.
Limit values
MSHA silica Limit Values
Every value US MSHA publishes for the parameter below, with its averaging period, as the standard states it.
Who it applies to
Who Must Comply
Operators of US mines. The compliance date was April 14, 2025 for coal mines and April 8, 2026 for metal and nonmetal mines.
Monitoring
How Monitoring Demonstrates Compliance
Compliance rests on full-shift sampling of each miner who may be exposed, with a respirable sampler analyzed for crystalline silica. Below the action level, a second sample is taken within three months; at or above it, sampling continues every three months; above the PEL, the operator takes corrective action and samples again. Real-time respirable dust monitoring shows which tasks and places generate dust and whether controls such as cab filtration are working, between those samples.
Recommended
best match-
Thiamis connects 1 instrument
A gateway that connects the third-party instruments you choose to the Aethair Platform.
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Trolex Particulate & Dust Monitors
Respirable Crystalline SilicaTrolex real-time dust and silica monitors for harsh mining and industrial environments: the Air XD fixed optical dust…
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Who measures each parameter
| Parameter |  Aethair PRO |  Aethair IAQ | External |
|---|---|---|---|
| Respirable Crystalline Silica | — | — | 1 instrument via Thiamis |
Devices
Devices That Cover MSHA silica
How much of this standard one Aethair monitor covers, followed by the third-party instruments in the sensor catalog that measure its parameters. Each connects to Environet through a Thiamis gateway, which adds whatever the monitor leaves out.
Covers it on its own
Solutions
Solutions Judged Against MSHA silica
Cabin Air Quality
Respirable dust, gases, and blast monitoring
Questions
MSHA silica FAQ
What is the MSHA silica limit?
50 µg/m³ of respirable crystalline silica for a full shift, calculated as an 8-hour time-weighted average, with an action level of 25 µg/m³.
When did the MSHA silica rule take effect?
April 14, 2025 for coal mines and April 8, 2026 for metal and nonmetal mines.
Does a real-time dust monitor satisfy the MSHA rule?
No. Compliance rests on full-shift sampling analyzed for crystalline silica; real-time monitoring helps control dust between samples.
Monitor Against MSHA silica
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