Agent Name

Soapstone

Major Category

Mineral Dusts

Synonyms

Massive talc; Soapstone silicate; Steatite;

Category

Other Mineral Dusts

Description

Odorless, white-gray powder; [NIOSH]

Sources/Uses

Soapstone is used as a paint, rubber, and soap pigment; also used as a lubricant for machinery and a mold release. [ACGIH]

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]

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data

PEL (OSHA)

20 mppcf, <1% crystalline

IDLH (NIOSH)

3000 mg/m3

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).

Explanatory Notes

TLV withdrawn in 2011; See "Talc." [ACGIH]

Adverse Effects
Fibrogenic

Yes

Links to Other NLM Databases
Toxicity Information

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Related Information in HazMap
Diseases

Occupational diseases associated with exposure to this agent:

Processes

Industrial Processes with risk of exposure: