Antimony trioxide is used as a flame retardant synergist in the plastic casings of electronic devices — it is combined with halogenated flame retardants to achieve required flammability ratings. It is present in the housings of computers, televisions, gaming consoles, printers, and mobile phones. Antimony trioxide is classified by IARC as a possible human carcinogen (Group 2B) and is released as fine particles and vapour during device use, from ageing plastics, and during e-waste processing. Despite its widespread presence in consumer electronics, it receives minimal consumer awareness.
Where it's found
Plastic casings of computers, laptops, televisions, and gaming consoles contain antimony trioxide as a flame retardant synergist — combined with brominated or chlorinated flame retardants. Printer and photocopier housings. Mobile phone and tablet casings in older devices. The plastic covers of circuit boards and internal components. Textiles treated with antimony-based flame retardants (some upholstery and curtain fabrics). PET plastic bottles and food packaging — antimony leaches from PET into beverages stored in plastic bottles, originating from the antimony catalyst used in PET manufacturing rather than flame retardant use.
Routes of exposure
Inhalation of fine antimony particles and vapour released from heated or degrading device plastics during extended device operation. Skin contact with device casings. Ingestion from hand-to-mouth transfer after handling devices, particularly relevant for children. Inhalation during e-waste processing — device casings are shredded during recycling, generating antimony-containing dust. Dietary ingestion from PET bottle leaching — antimony migrates from PET plastic into beverages, with migration increasing substantially with temperature and storage duration.
Health concerns
Antimony trioxide is classified by IARC as a Group 2B possible human carcinogen based on sufficient evidence of lung tumour induction by inhalation in rats and mice. Antimony compounds cause respiratory irritation, skin irritation, and at higher exposures cardiac arrhythmia and liver toxicity. Antimony leaching from PET plastic bottles into beverages is well documented — concentrations increase with storage time, temperature, and bottle reuse. The EFSA has evaluated antimony in PET food contact materials and set migration limits. Workers in antimony smelting and device manufacturing face occupational exposure substantially higher than consumer use.
Evidence
IARC Group 2B classification for antimony trioxide is based on adequate animal evidence. Human carcinogenicity data are limited to occupational studies. PET bottle leaching of antimony is analytically confirmed across many studies; the health significance at typical consumption levels is under review. Consumer exposure from device casing emissions is less well characterised than occupational or PET bottle routes.
Who's most at risk
Workers in electronics manufacturing, e-waste recycling, and antimony smelting have the highest exposure. Children who spend extended time near operating electronic devices and who handle device casings may receive higher relative inhalation and dermal exposure. People who store beverages in PET bottles in warm conditions (car gloveboxes, heated rooms) have higher dietary antimony intake.
Regulatory status
RegulationAntimony trioxide is restricted under RoHS for some applications but with exemptions for flame retardant use in specific equipment categories. ECHA has assessed antimony compounds under REACH. EU Regulation (EC) 10/2011 sets a migration limit of 0.04 mg/kg for antimony from plastic food contact materials. No specific limit for antimony emissions from consumer electronic device casings. The UK retained relevant food contact and RoHS restrictions post-Brexit.
How to reduce your exposure
Do not store water or beverages in PET plastic bottles in warm conditions — refrigerate or transfer to glass or stainless steel. Do not reuse single-use PET bottles, as surface degradation increases antimony migration. Ensure good ventilation in rooms with multiple operating electronic devices, particularly during extended gaming or workstation sessions. Take old electronics to certified e-waste facilities. Choose drinking water containers made from glass or stainless steel rather than plastic as a default.
The nutrition connection
Antimony trioxide illustrates a category of chemical hazard that comes from the technology infrastructure of daily life — the device casing sitting on every desk and in every pocket — rather than from food, water, or personal care. The nutritional connection is again through PET bottle leaching: the choice of drinking vessel (glass or steel versus plastic) is simultaneously a microplastic, antimony, and bisphenol risk reduction decision. Hydrating from glass or stainless steel containers is one of the simplest and most broadly protective single product substitutions available across multiple chemical exposure categories.