Agent Name

Mica, respirable dust

CAS Number


Major Category

Mineral Dusts


Biotite; Lepidolite; Margarite; Muscovite; Phlogopite; Roscoelite; Zimmwaldite; [NIOSH]


Other Mineral Dusts


Colorless, odorless flakes or sheets of hydrous silicates; [NIOSH] 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]


Mica, mainly muscovite and phlogopite, contains less than 1% quartz. Other species of mica are biotite, lepidolite, zimmwaldite, and roscoelite. Mica is used in shingles, wallpaper, and insulation. It is also used in oil well drilling, mold releasing, filtering, and in manufacturing heat-resistant windows. [ACGIH] Sericite is a variety of white mica; it is similar to muscovite and is used as a filler, carrier, and lubricant; [Reference #1]


Mica workers in India with 18 years of exposure to 20 mppcf showed evidence of mild pneumoconiosis on chest x-rays. [ACGIH] A mixed-dust pneumoconiosis reported in mica miners appears to be related to free silica contamination of ores. [Rosenstock, p. 412] The existence of a mica pneumoconiosis is controversial and is based on a few case reports. [Hendrick, p. 170] Three cases of pneumoconioses were diagnosed among sericite plant workers in Parana, Brazil. 44 workers with an average 13.5 years of exposure were examined. 52% of workers had chest x-ray opacities, and 18% had reduced FEV1 on pulmonary function testing. [Reference #1] "Occupational exposure to mica dust is responsible for diffuse infiltrative lung disease by overload processes." [Reference #2]

Reference Link

Pneumoconiosis after sericite inhalation. [Occup Environ Med. 2005] - PubMed Result

Exposure Assessment
Skin Designation (ACGIH)

Insufficient data




3 mg/m3, respirable fraction


20 mppcf, < 1% crystalline silica


1500 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 mica would impede escape or cause any irreversible health effects within 30 minutes.

Reference Link

Mica dust and pneumoconiosis: example of a pure occupational exposure in a muscovite milling unit.

Adverse Effects


Links to Other NLM Databases
Health Studies

Human Health Effects from Hazardous Substances Data Bank:

Toxicity Information


Chemical Information

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Biomedical References

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Related Information in HazMap

Occupational diseases associated with exposure to this agent:


Industrial Processes with risk of exposure: