Asbestos Number
In environmental health, occupational safety, and hazardous materials transportation, an asbestos number can refer to several distinct numerical identifiers. Depending on the operational context, professionals and property owners may be searching for Chemical Abstracts Service (CAS) registry numbers, United Nations hazardous cargo transportation codes, OSHA numerical exposure limits, or official regulatory emergency hotline numbers.
Chemical Abstracts Service (CAS) Numbers and Mineral Identifiers
In chemical indexing, environmental toxicology, and industrial safety data sheets (SDS), an asbestos number almost universally designates an official Chemical Abstracts Service (CAS) registry number. Because asbestos is a generic commercial umbrella term rather than a single chemical compound, the American Chemical Society assigns unique numerical identifiers to distinguish between the six regulated fibrous silicate minerals belonging to the serpentine and amphibole mineralogical families.
Specifying the exact CAS number is vital for environmental health laboratories, customs clearing agents, and regulatory reporting. Chrysotile, a curly sheet silicate representing approximately 95% of historical commercial asbestos applications, is classified under CAS number 12001-29-5. In contrast, needle-like amphibole minerals—such as amosite (brown asbestos, CAS 12172-73-5) and crocidolite (blue asbestos, CAS 12001-28-4)—carry distinct numbers due to their extreme acid resistance, elevated tensile strength, and enhanced biopersistence within pulmonary tissue.
| Mineral Variety | Mineralogical Family | Official CAS Registry Number | Common Industrial Name | Primary Historical Industrial Uses |
|---|---|---|---|---|
| Chrysotile | Serpentine (Sheet Silicate) | 12001-29-5 | White Asbestos | Brake linings, drywall mud, cement sheets, roofing |
| Amosite | Amphibole (Double-Chain Silicate) | 12172-73-5 | Brown Asbestos | Thermal pipe lagging, acoustic ceiling tiles, fire doors |
| Crocidolite | Amphibole (Double-Chain Silicate) | 12001-28-4 | Blue Asbestos | Acid battery casings, steam pipe insulation, gas masks |
| Anthophyllite | Amphibole (Double-Chain Silicate) | 77536-67-5 | Anthophyllite Asbestos | Cement board fillers, laboratory counters, plastics |
| Tremolite | Amphibole (Double-Chain Silicate) | 77536-68-6 | Tremolite Asbestos | Contaminant in vermiculite attic insulation and talc |
| Actinolite | Amphibole (Double-Chain Silicate) | 77536-66-4 | Actinolite Asbestos | Paints, sealants, joint drywall compounds |
United Nations Hazardous Numbers, Exposure Limits, and Contact Numbers
When transporting hazardous materials on roadways, railways, or cargo vessels, emergency first responders and freight carriers rely on United Nations (UN) four-digit hazardous cargo numbers. Under the US Department of Transportation (DOT) and international dangerous goods regulations (IMDG and ADR), blue and brown amphiboles (crocidolite and amosite) are designated as UN 2212 (Class 9 hazardous substance). Chrysotile white asbestos is assigned UN 2590. These numbers appear on diamond transport placards and shipping manifests to guide emergency containment during transportation accidents.
In occupational health, numerical standards define worker exposure thresholds. Under OSHA standard 29 CFR 1926.1101, the Permissible Exposure Limit (PEL) is set at 0.1 fiber per cubic centimeter of air (0.1 f/cc) calculated as an 8-hour time-weighted average (TWA). OSHA also enforces an Excursion Limit of 1.0 f/cc over a 30-minute sampling window. For building materials, the EPA NESHAP defining number is greater than one percent (>1%) asbestos content by weight or volume, below which a material is classified as non-ACM for specific federal disposal provisions.
| Regulatory Classification | Official Designated Number | Enforcing Standard / Agency | Operational Significance |
|---|---|---|---|
| UN Transport Code (Amphiboles) | UN 2212 | US DOT / IMDG Class 9 | Governs shipment of hazardous crocidolite and amosite waste |
| UN Transport Code (Chrysotile) | UN 2590 | US DOT / IMDG Class 9 | Governs transport of white chrysotile materials to landfills |
| OSHA 8-Hour TWA Limit | 0.1 f/cc (fiber per cubic cm) | OSHA 29 CFR 1926.1101 | Maximum allowable airborne occupational exposure level |
| OSHA 30-Minute Excursion Limit | 1.0 f/cc (fiber per cubic cm) | OSHA 29 CFR 1926.1101 | Short-term airborne ceiling during intensive abatement tasks |
| EPA Regulated ACM Threshold | Greater than 1% (>1%) | EPA NESHAP 40 CFR 61 | Numerical threshold defining regulated hazardous materials |
| EPA TSCA Technical Hotline | 1-202-554-1404 | US EPA Information Desk | Public phone line for asbestos regulations and assistance |
For individuals facing an immediate building emergency, discovering exposed insulation, or reporting illegal dumping, an asbestos number can also refer to official government hotline phone numbers. In the United States, concerns can be directed to the EPA Asbestos and Small Business Ombudsman at 1-800-368-5888 or the OSHA Emergency Hotline at 1-800-321-6742 (OSHA).
Environmental professionals handling hazardous manifests must accurately record both the CAS number and UN transport number on waste shipment records (WSR). Discrepancies between physical laboratory analysis and shipping documents can result in substantial regulatory fines from the Department of Transportation or rejection of waste containers at licensed disposal facilities.
How to Identify and Verify an Asbestos Number
Step-by-step method to locate the correct CAS number, UN code, or regulatory threshold for asbestos materials.
Identify the Operational Context of the Number
Determine whether the requested number refers to a chemical CAS identifier, transport code, exposure limit, or agency hotline.
Check the Material Safety Data Sheet (SDS)
Locate Section 3 (Composition / Ingredients) of the SDS to verify the exact CAS number for the specific mineral variety.
Consult the DOT Emergency Response Guidebook
Cross-reference UN 2212 (amphiboles) or UN 2590 (chrysotile) for hazardous transport, placarding, and packaging specifications.
Confirm Compliance with OSHA Numerical Thresholds
Review personal air monitoring results against OSHA’s 8-hour TWA limit of 0.1 f/cc and 30-minute excursion limit of 1.0 f/cc.
Frequently Asked Questions (8 Questions Answered)
Q1: What is the CAS number for chrysotile asbestos?
The official Chemical Abstracts Service (CAS) registry number for chrysotile white asbestos is 12001-29-5.
Q2: What is the UN number for transporting asbestos waste?
UN 2212 designates hazardous amphibole minerals (amosite, crocidolite), while UN 2590 designates chrysotile white asbestos.
Q3: What is the OSHA permissible exposure limit number for asbestos?
The OSHA permissible exposure limit is 0.1 fibers per cubic centimeter of air (0.1 f/cc) as an 8-hour time-weighted average.
Q4: What percentage defines a building material as containing asbestos?
Under EPA and OSHA regulations, any building material containing greater than one percent (>1%) asbestos is legally regulated.
Q5: What phone number do I call to report illegal asbestos removal?
In the United States, you can contact the OSHA National Emergency Hotline at 1-800-321-6742 or your state environmental department.
Q6: What is the CAS number for amosite brown asbestos?
The official CAS registry number for amosite (grunerite asbestos) is 12172-73-5.
Q7: Why do different asbestos minerals have different CAS numbers?
CAS numbers differentiate specific chemical structures; chrysotile is a serpentine sheet silicate, while amphiboles are double-chain silicates.
Q8: What is the EPA TSCA asbestos information hotline number?
The EPA Toxic Substances Control Act (TSCA) Assistance Information Service can be reached at 1-202-554-1404.
Final Thoughts & Key Takeaways
Whether interpreting a chemical safety data sheet featuring a CAS registry number, verifying shipping placards with UN hazardous codes, or calculating workplace compliance against OSHA’s 0.1 f/cc permissible exposure limit, understanding the specific asbestos number in context is vital. These precise numerical metrics ensure scientific accuracy, regulatory compliance, and maximum protection for workers and communities.