Antimony in PET Bottles: Should You Worry About Your Water Bottle?
The science on antimony leaching from PET plastic water bottles. When it's a real risk, and the best reusable alternatives.
Antimony trioxide is used as a catalyst in PET plastic production and remains as a trace residue. At room temperature, leaching is well below WHO limits. But when PET bottles are exposed to heat (car dashboards, sunlight, hot storage), antimony leaching increases 2–90x and can approach or exceed the EPA drinking water standard of 6 ppb. Don’t reuse single-use PET bottles, and switch to reusable alternatives.
What Is Antimony and Why Is It in Plastic?
Antimony trioxide (Sb₂O₃) is a catalyst used during the polymerization of PET (polyethylene terephthalate) — the plastic used in virtually all single-use water bottles, soda bottles, and many food containers marked with recycling code #1.
After manufacturing, trace amounts of antimony remain embedded in the plastic. Under normal conditions, the amount that leaches into water is extremely small. The concern arises with heat, time, and repeated use.
When Antimony Becomes a Problem
Maximum contaminant level for antimony in drinking water is 6 ppb (parts per billion).
Studies consistently show leaching below 1 ppb at 25°C — well within safe limits.
A 2016 study in Journal of Environmental Monitoring found that storing PET bottles at 60°C (140°F) for one week increased antimony leaching up to 90x vs. room temperature.
UV exposure also accelerates leaching, even at moderate temperatures.
Antimony is classified as a possible carcinogen (IARC Group 2B as antimony trioxide). Chronic exposure affects the lungs, heart, and liver.
Simple Precautions
Never leave PET bottles in hot cars. This is the single most impactful step you can take.
Don’t refill single-use PET bottles. Repeated filling, squeezing, and washing degrades the plastic and increases leaching.
Store bottled water in a cool, dark place. A pantry or refrigerator is ideal. Avoid garages and storage sheds.
Switch to a reusable bottle. Stainless steel and glass eliminate the issue entirely and pay for themselves quickly.
Better Alternatives
Double-wall vacuum-insulated 18/8 stainless steel. Keeps water cold for 24 hours. No plastic touches the water — the entire interior is steel.
Borosilicate glass with a protective silicone sleeve. Completely inert — glass doesn’t leach anything regardless of temperature or time.
Made from Eastman Tritan (not PET), which is BPA-free, antimony-free, and does not use bisphenol catalysts. Independently tested for estrogenic activity.
BPA-free bottle with a built-in activated carbon filter that reduces chlorine taste, microplastics, and some contaminants as you drink.
Sources
- EPA — Antimony Drinking Water Standard — https://www.epa.gov/ground-water-and-drinking-water/national-primary-drinking-water-regulations
- Journal of Environmental Monitoring — Antimony leaching from PET (2016) — https://pubs.rsc.org/en/journals/journalissues/em
- IARC — Antimony Trioxide Classification — https://monographs.iarc.who.int/
- Water Research — PET bottle leaching review (2018) — https://www.sciencedirect.com/journal/water-research
Explore Connections
Dive deeper into related hazards, similar chemical profiles, or safe material equivalents.