Antimony

Antimony has been used since antiquity — ancient Egyptians used antimony sulfide as eye cosmetic (kohl), and it was used in medieval medicine [1]. Industrially, antimony trioxide is the most important compound, used as a flame retardant in plastics, textiles, and electronics — including the circuit boards in every electronic device and the flame-retardant foam in mattresses and furniture. It is also used as a catalyst in PET plastic production, which is why trace antimony is found leaching from PET bottles [2]. Other uses include lead-antimony battery grids (car batteries), ammunition (lead-antimony alloy bullets), and as a pigment. Mining and smelting operations in China, Russia, and Bolivia are the dominant global sources, with smelter communities facing significant air and soil contamination [3].

PET beverage bottles are a surprisingly widespread antimony exposure route — antimony trioxide is used as a catalyst in PET production and residual antimony migrates into the water over time, accelerated by heat [1]. Studies have found antimony levels in bottled water that increase significantly when bottles are stored at high temperatures (hot cars, warehouses). The levels are generally below the US MCL of 6 ppb but above background [2]. Occupational exposures are the most significant: antimony ore smelting, ammunition manufacturing (handling antimony-lead alloys), and flame retardant compounding produce dust and fume with high antimony content. Drinking water from distribution systems using antimony-bearing solder or pipes can have elevated levels [3].

Antimony trioxide is classified as a possible human carcinogen (IARC Group 2B) based on lung tumor induction in animals and lung cancer elevation in smelter workers [1]. Occupationally, antimony causes "antimony pneumoconiosis" — a lung disease from inhalation of antimony dust — as well as skin eruptions (antimony spots) and cardiac arrhythmias. Trivalent antimony inhibits thiol-dependent enzymes, similar to arsenic, disrupting multiple metabolic pathways [2]. Antimony trichloride and other reactive antimony compounds cause acute irritation of the respiratory tract and eyes. The cardiovascular effects of antimony — including ECG changes and sudden death in heavily exposed workers — are a significant occupational concern [3].

Workers in antimony smelting, ammunition manufacturing, and flame retardant production face the highest occupational exposures [1]. Communities near antimony smelters and mining operations have elevated environmental exposures. People who regularly store and drink water from PET bottles kept in hot environments may have modestly elevated antimony intake [2]. Workers who handle antimony-containing solders in electronics manufacturing and plumbers who use antimony-bearing materials face additional exposures.

Do not store PET water bottles in hot environments — keep water in glass, stainless steel, or HDPE (#2) containers for storage, especially in vehicles or outdoors in warm weather [1]. If you use bottled water regularly, consider switching to home-filtered water in reusable containers. For drinking water: the EPA MCL of 6 ppb applies to public water systems; private well testing should include antimony if industrial activity is nearby [2]. Workers in antimony-exposure industries: use local exhaust ventilation, NIOSH-approved P100 respirators for dust-generating operations, and have annual monitoring of blood or urine antimony levels [3].