Often when we post about a company crafting something from recycled PET (polyester) someone will let lose a rant about antimony. And they aren't, as some might assume, opposing the dollars and cents economy. Rather, they are concerned about a naturally occurring, brittle, silver-white metal that can be used as a catalyst in the polymerisation of polyester resin.
Lauded Cradle-to-Cradle ecodesigner and toxins campaigner William McDonough. has been on Antimony's case for years. His company MBDC says of the stuff: "Along with being a carcinogen, antimony is toxic to the heart, lungs, liver and skin. Long-term inhalation of antimony trioxide, a by-product of polymer production, can cause chronic bronchitis and emphysema." And all this may be true. Although we do note that the US Agency for Toxic Substances and Disease Registry (ATSDR) are a little more circumspect: "We do not know if antimony can cause cancer or birth defects, or affect reproduction in humans."
But will donning clothes made of recycled PET polyester cause the wearer to suffer the scary symptoms listed above? Seems not. The ATSDR again: "The antimony oxide that is added to many materials for fire protection is very tightly attached to these materials and does not expose people to antimony."
So why are people getting their knickers in a twist over Antimony? Mostly because its use as a production additive can see it released as a industrial pollutant into the air and water where those close to factories using it may be at risk.
Antimony-free polyester is therefore a better option for the air we breath and the water we drink. Does such a thing exist? Yep. Back in 2001 a Canadian fabric manufacturer, Victor Innovatex, released Eco-Intelligent Polyester for commercial upholstery and furnishings. Working with McDonough's team they came up with a polyester, which uses a titanium and silica-based catalyst, with no known toxic effects.
Now you're probably wondering if any of this antimony-free stuff is available in clothing too. Affirmative, but supply is currently rather niche-like.
Mountain Equipment Co-op (MEC), also of Canada, have their Breeze jacket (seen above) that doesn't contain the heavy metal. And when we spoke with Nau back in 2006, they told us that, "Currently 75 denier is antimony free and our supplier is in the R & D phase of developing 50 denier that is antimony free. When that is accomplished well over 50% of our styles that use recycled polyester will be antimony free."
Patagonia, the pioneer in recycled polyester apparel, are also well aware of the issue, with the company's founder Yvon Chouinard commenting in 2004, "We're constrained by the fact that some technologies don't exist yet. Like we make a lot of products out of recycled soda-pop bottles -- polyester and fleece. Well, those bottles have a carcinogenic heavy metal, antimony, and we are working with the mills to take the antimony out before they make the fiber."
[we also covered the antimony issue in PET bottles ages too. Another good reason not to drink either bottled water or that fizzy carbonated sugar water stuff.]
So to recap: antimony oxide is not a nice thing to be drinking or breathing. And although wearing it won't harm you, it's use in the production cycle can result in it being released as a toxic industrial pollutant. Progressive companies are making strong efforts to find alternatives.
Antimony pic from Wikipedia