| Agent Name |
Soapstone |
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| Major Category |
Mineral Dusts |
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| Synonyms |
Massive talc; Soapstone silicate; Steatite; |
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| Category |
Other Mineral Dusts |
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| Description |
Odorless, white-gray powder; [NIOSH] |
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| Sources/Uses |
Soapstone is used as a paint, rubber, and soap pigment; also used as a lubricant for machinery and a mold release. [ACGIH] |
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| Comments |
Soapstone does not have a precise mineralogical definition. It is at least 50% talc. The TLV for soapstone containing no asbestos and less than 1% silica is based on the fibrogenic potential of talc. [ACGIH] Crystalline silica not bound to other minerals is "free" silica. Silicates are minerals in which silicon and oxygen are combined with other elements. [Rom, p. 364] |
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| Exposure Assessment |
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| Skin Designation (ACGIH) |
No |
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| TLV (ACGIH) |
6 mg/m3(inhalable fraction), 3 mg/m3(respirable fraction) |
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| PEL (OSHA) | 20 mppcf |
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| IDLH (NIOSH) |
3000 mg/m3 |
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| Excerpts from Documentation for IDLHs |
Basis for revised IDLH: The available toxicological data contain no evidence that an acute exposure to a high concentration of soapstone would impede escape or cause any irreversible health effects within 30 minutes. However, the revised IDLH for soapstone is 3,000 mg/m3 based on being 500 times the NIOSH REL of 6 mg/m3 (500 is an assigned protection factor for respirators and was used arbitrarily during the Standards Completion Program for deciding when the "most protective" respirators should be used for particulates). |
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| Explanatory Notes |
See 2008 Notice of Intended Changes. [ACGIH] |
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| Links to Other NLM Databases |
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