Agent Name
Alternative Name
Indium and compounds
CAS Number
7440-74-6; varies
In, varies
Major Category
Indium metal; Indium compounds; Indium trichloride; Indium oxide; Indium sulfate; Indium sulfide; Indium sesquioxide; Colliodal indium hydroxide; Trimethylindium; Indium phosphide; Indium arsenide; [Nordberg, p. 845]
Metals, Inorganic Compounds
Ductile, shiny, silver-white metal that is softer than lead; [NIOSH] Oxidation states: 1+, 2+, and 3+; Only 3+ stable in water; [Nordberg, p. 845]
Used in bearings, solder, yellow glass, lubricants, motion picture screens, mirrors, transistors, and infrared detectors; [HSDB] Used to make semiconductors (indium phosphide and indium arsenide) and nanoparticles (indium phosphide); Also used in ceramic glazes, electroplating, dental alloys, solders, and medical radioisotopes; [Nordberg, p. 846] Increased potential for inhalation exposure to aerosols of powders or ceramics: manufacturing of inorganic indium compounds, ITO sputter target resurfacing between deposition runs, cleaning sputter chamber interior walls and shields, and abrasive blasting to remove residues on sputter chamber parts; Low indium exposure: use of indium metal solders, reflow of indium metal targets, alloying of indium metal with other metals, fabrication of InP-based semiconductor devices, and preparation of solder pastes; Also used to make nuclear control rods; [Reference #2]
Ionic indium is toxic to the kidneys; Colloidal indium is toxic to the liver; A single case report of pulmonary fibrosis: worker was exposed for 4 years to indium-tin oxide in a plant making flat-panel plasma screens; [Nordberg, p. 845, 851] A study of interstitial lung disease in indium-processing workers suggested that "inhaled indium could be a potential cause of occupational lung disease." [Reference #1] "A TLV-TWA of 0.1 mg/m3, measured as indium, is recommended for occupational exposure to indium and its compounds. This value is intended to minimize the potential for adverse effects on the lungs, including pulmonary edema, acute pneumonitis, and possible skeletal and gastrointestinal disorders." [ACGIH] See "Indium tin oxide."
Biomedical References

Exposure Assessment

Skin Designation (ACGIH)
Insufficient data
0.1 mg/m3, as In
Explanatory Notes
mp = 156.6 deg C; [Nordberg, p. 845] "NIOSH data suggest that it may take only 15 min of pneumatically sanding on an ITO target to reach 0.1 mg/m3 as an 8-hr TWA." [Reference #2]

Adverse Effects

Toxic Pneumonitis

Diseases, Processes, and Activities Linked to This Agent