Soapstone

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]
Biomedical References

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TLV withdrawn in 2011; See "Talc."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

Diseases, Processes, and Activities Linked to This Agent

Diseases

Occupational diseases associated with exposure to this agent:

Processes

Industrial Processes with risk of exposure: