Antimony Trioxide Profile

Antimony Trioxide Profile

General Information

Antimony trioxide (Sb₂O₃) is a slightly soluble, white crystalline powder.[1] It is produced by smelting antimony-containing ores[1] or reacting antimony trichloride with water.[2] Antimony is not abundant in the earth’s crust.[3] Antimony trioxide may also be referred to as diantimony trioxide (DAT), antimony oxide, or in manufacturing as antimony white.[4] There are numerous other synonyms and product names; see the Hazardous Substances Data Bank (HSDB) for more information.[4]

Antimony trioxide was last classified by the International Agency for Research on Cancer (IARC) in 1989 as Group 2B, possibly carcinogenic to humans, based on inadequate evidence in humans and sufficient evidence in animals.[1] Antimony trioxide is a respiratory carcinogen in female rats.[1]

The epidemiological literature on exposure to antimony trioxide is not extensive and is limited by difficulty in controlling for confounding variables. Recent reviews of studies report excesses of lung cancer in antimony exposed smelter workers, but factors such as smoking, exposures to PAHs and other metals (e.g. arsenic), were not appropriately controlled.[2,5]

Antimony trioxide has also been linked to pneumoconiosis, bronchitis, and airway inflammation.[3] Digestive and neurologic symptoms have been reported from high levels of exposure, but causal relationships have not been established.[3] An early study reported that exposure is associated with an increase in spontaneous abortions, premature birth, and slow growth rates in offspring.[6] The study’s control of confounding variables and exposure assessment techniques, however, were unclear.[7]

Regulations and Guidelines

Occupational exposure limits (OEL)[8,9,10,11,12,13,14,15,16,17,18,19,20,21,22]

Canadian environmental guidelines and standards*

*Standards are legislated and legally enforceable, while guidelines (including Ontario ambient air quality criteria) describe concentrations of contaminants in the environment (e.g. air, water) that are protective against adverse health, environmental, or aesthetic (e.g. odour) effects

Canadian agencies/organizations

Antimony trioxide was not included in other Canadian government guidelines, standards, or chemical listings reviewed.

Canadian Production and Trade

Antimony trioxide is primarily used to create household flame retardants and plastic (polyethylene terephthalate).[38]

Antimony is naturally occurring in the Cordilleran (west coast) and Appalachian (east coast) regions of Canada.[39] Approximately 401 tonnes of antimony is mined in Canada annually, and it is considered a “critical mineral for the economic success of Canada”.[39,40] China, Belgium and France are the highest exporters globally, each exporting over 10,000 tonnes annually.[41]

At full capacity, Beaver Brook Antimony Mine Inc. in Newfoundland will mine approximately 160,000 tones of antimony per year.[42,43] Operations were temporarily suspended in November 2020 due to the COVID-19 pandemic however mining resumed at the end of September 2021.[42]

Production and trade

t = tonne

Environmental Exposures Overview

The main source of exposure to antimony trioxide for the general population is through dermal contact with household items that contain flame retardants, such as paint, mattress covers and furniture upholstery.[46] However, Environment Canada reports that exposures from this pathway are low.[46]

Other sources of environmental exposure include food, drinking water, and air.[3,46] Overall, levels of antimony trioxide in water are low due to its poor solubility in water.[46] Higher levels of exposure may occur around smelters, incinerators, and near combustion of petroleum and coal products.[3] Higher levels of exposure to antimony trioxide have also been associated with smokers and those exposed to secondhand smoke.[47]

Searches of Environment Canada’s National Pollutant Release Inventory (NPRI) and the US Household Products Database yielded the following results on current potential for exposure to antimony trioxide in Canada:

NPRI and US Household Products Database

Occupational Exposures Overview

Inhalation is the most important route of occupational exposure, however oral and dermal contact are also a concern.[3]

CAREX Canada estimates that approximately 8,700 Canadians are exposed to antimony trioxide in the workplace. The primary industrial groups exposed are public administration, followed by glass and glass product manufacturing. In terms of occupations, the largest exposed groups are police officers (exposed in firing ranges), welders and related machine operators, artisans and craftspersons, and glass forming and finishing machine operators and glass cutters.

Other workers likely to be exposed include those involved in: antimony trioxide production; antimony processing, smelting, and packaging of antimony compounds; production of ceramics and alloys that contain Sb₂O₃; and manufacture and application of flame retardants.[36]

Workers in facilities that recycle lead-acid batteries may also be exposed to antimony.[50] Firefighters and other emergency workers may be exposed when materials containing antimony trioxide as a fire retardant combust.[36] Exposures may also occur for workers involved producing PET bottles, where antimony trioxide is used as the main catalyst.

For more information, see the occupational exposure estimate for antimony trioxide.

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