Asbestos (1332-21-4)
Asbestos is a particulate / dust with CAS Registry Number 1332-21-4. Under the OSHA air contaminants standard (29 CFR 1910.1000), its Permissible Exposure Limit (PEL) — the legal 8-hour time-weighted average (TWA) for general industry — is 0.1 mg/m3. The principal target organs are the Lungs; pleura (mesothelioma), and workplace air is sampled and analyzed by NIOSH 7400.
Exposure Limits at a Glance
| Limit | Value | Basis |
|---|---|---|
| OSHA PEL (8-hr TWA) | 0.1 mg/m3 | 29 CFR 1910.1000 |
| NIOSH REL | See note below | NIOSH Pocket Guide |
| Hazard Class | Particulate / Dust | Particulate |
| Target Organs | Lungs; pleura (mesothelioma) | NIOSH / OSHA |
| Sampling Method | NIOSH 7400 | NIOSH Manual of Analytical Methods |
NIOSH REL note: NIOSH RELs are often 10x lower than the PEL and include a respirable fraction. The REL is a non-regulatory recommendation; where a NIOSH REL exists it is typically more protective than the OSHA PEL.
How It Enters the Body & Health Effects
Exposure to Asbestos is assessed against the Lungs; pleura (mesothelioma) — the organ systems most consistently affected in occupational studies. Employers must ensure no employee’s 8-hour TWA exceeds the 0.1 mg/m3 PEL, and must use engineering controls, work practices, and — where required — respiratory protection to keep exposures at or below that level.
- Hazard class: Particulate / Dust. Particulate-class agents are managed with the hierarchy of controls (elimination, substitution, engineering controls, administrative controls, then PPE).
- Monitoring: collect personal air samples in the breathing zone and submit them under NIOSH 7400 for laboratory analysis.
- Medical surveillance: consult the OSHA substance-specific standards and the NIOSH Pocket Guide when the target organs are the Lungs; pleura (mesothelioma).
Sampling & Compliance Notes
- Determine whether the exposure is a full-period 8-hour TWA or a short-term / ceiling scenario. Ceiling and STEL excursions apply to several Particulate-class agents regardless of the 8-hour average.
- Calibrate personal sampling pumps before and after each shift and record flow rates; method NIOSH 7400 specifies media, flow, and analysis.
- Compare analytical results to the OSHA PEL of 0.1 mg/m3 and the NIOSH REL. Document the higher of the two for internal exposure-control targets.
- Where the PEL includes a “skin” notation, dermal absorption can contribute to the dose — glove selection and hygiene facilities are part of compliance.
Frequently Asked Questions
What is the OSHA PEL for Asbestos?
The OSHA Permissible Exposure Limit (8-hour TWA) for Asbestos is 0.1 mg/m3.
What is the CAS number for Asbestos?
The CAS Registry Number for Asbestos is 1332-21-4.
What are the target organs for Asbestos?
The primary target organs are the Lungs; pleura (mesothelioma).
How do you measure Asbestos in workplace air?
Use NIOSH analytical method NIOSH 7400 for air sampling and laboratory analysis.
What hazard class is Asbestos?
It is classified here as a Particulate / Dust (Particulate).