Indium tin oxide

Agent Name
Indium tin oxide
CAS Number
Major Category
ITO; Tin indium oxide; [ChemIDplus]
Metals, Inorganic Compounds
Gray-yellow powder; [HSDB]
"ITP can be sintered or unsintered, but typically the occupational exposure is to the sintered form. Sintering uses heat and pressure to combine indium oxide and tin oxide powders to form compressed disks called sputtering targets. . . . The main use of ITO is in producing transparent conductive films on glass or plastic panels used in electronic devices and other products, including touch panels, plasma displays, flat panel displays, solar panels, cathode-ray tubes , energy efficient windows, gas sensors, and photovoltaics." [IARC Monographs 118] "Exposures may occur in the production of the base material, processing and working of 'tiles' used as a base source of the compound, and machining or recycling of the finished products." [ACGIH] See "Effects of a powered air-purifying respirator intervention on indium exposure reduction and indium related biomarkers among ITO sputter target manufacturing workers." [PMID 26771526]
"In the case reports of ITO-exposed workers with interstitial lung disease, also called indium lung disease, increased accumulation of inflammatory cells including alveolar macrophages, lymphocytes, and plasma cells in the airways/lung was described. . . . In two workers (a non-smoker aged 49 years and a smoker aged 39 years) exposed to airborne ITO dust at an ITO-producing facility in the USA, pulmonary alveolar proteinosis and indium in lung tissue specimens were seen. A case of pulmonary alveolar proteinosis was also reported in a Chinese male aged 29 years working with an ITO spraying process; his indium serum concentration was 151.8 µg/L. . . . In exposed humans, ITO induced interstitial lung disease associated with alveolar proteinosis and fibrosis. Similar effects were seen in exposed rats, mice, and hamsters. . . . Indium tin oxide is possible carcinogenic to humans." [IARC Monograph 118] "The risk of indium lung disease in the industries responsible for manufacturing ITO targets and reclaiming indium from spent targets is now well-established." [PMID 27747908] "Omae et al. (2011) reviewed 10 cases of occupational lung disease that correlated with workplace exposure to ITO: 7 cases in Japan, 2 cases in the United States and 1 case in China. In all the cases, workers were exposed to ITO from polishing, grinding, sanding, and or spray/sputter coating ITO metal. In all these cases, airborne ITO or In levels were not known or measured but are presumably elevated based on the nature of the employee's occupational task of grinding, sanding, etc. In all cases, either ground glass opacity in HRCT, obstructive or restrictive changes in pulmonary function tests were reported." ITO is a mild skin sensitizer. [ACGIH]
Biomedical References

Exposure Assessment

0.0001 mg/m3, as In, respirable particulate matter

Adverse Effects

Skin Sensitizer
IARC Carcinogen
Possible (2b)
ACGIH Carcinogen
Confirmed Animal

Diseases, Processes, and Activities Linked to This Agent


Occupational diseases associated with exposure to this agent: