WARNING: This product can expose you to Bisphenol A (BPA), which is known to the state of California to cause birth defects or other reproductive harm. www.p65warnings.ca.gov
What does this warning even mean?
tl;dr: California's Prop 65 requires us to post this warning because our frames contain trace amounts of BPA, a chemical used in the production of all hard plastics. The FDA level of safe exposure to BPA for an adult is 23mcg/per day/per lb of weight. To exceed this safe threshold, you would have to completely eat at least three pairs of sunglasses in a single day.
The long version: We are proud of our materials expertise and will not shy away from explaining our materials choice and standing by it:
We make our sunglasses from a recycled polycarbonate plastic. Polycarbonate is one of the most common types of plastic in existence: it’s your keyboard and mouse, your phone case, your ballpoint pen, your car cupholder, almost every hard plastic item you own. It’s strong, light, inert and has a ton of properties that we believe makes for the best sunglasses.
All hard plastics, including our sunglasses, contain trace amounts of BPA. BPA, also known as bisphenol-a, is a synthetic chemical that can mimic the hormone estrogen in the human body. Studies show mixed results on the harm caused by BPA, but since it mimics estrogen it can be harmful to the development of young children. The products of most concern for BPA are baby bottles and food containers, where BPA can transfer out of the plastic lining and directly into the food or liquid consumed by these sensitive groups.
BPA is a fundamental component of hard plastics production – when the polycarbonate plastic is synthesized, the BPA is polymerized into a stable plastic matrix. During this plastic-creation process, a small part of the BPA monomer does not polymerize and remains as a chemical. Touching polycarbonate plastic is generally not a problem, as an almost unmeasurable amount transfers from plastic to skin. A comprehensive study done by the Danish Ministry of the Environment found that under the worst case conditions, only .019 micrograms(mcg) of BPA migrates to skin per square centimeter of plastic contact per hour. In 2014, the FDA determined the daily safe exposure level to be 3,220mcg for a 140lbs person (23mcg per lb).
The concentration of BPA in our polycarbonate is approximately 50 parts per million and our frames weigh about 20 grams each, which means they contain about 1,000mcg of BPA per pair. In order to exceed to the FDA safe daily limit of 3,220mcg, you would have to completely eat at least three pairs of sunglasses in a single day.
Understandably, we don’t think there’s any cause for concern. But California’s Proposition 65 requires us to post this warning because BPA is present in our product. Thanks for reading this far, we hope it is informative and relieves your concern. (And please don’t eat your sunglasses, you’ll have much bigger problems than just trace BPA…)