Q: Can paper cash-register receipts be safely recycled? What about added to compost? I've read that receipts have high levels of bisphenol A (BPA), which is an endocrine disruptor.

—Barbara in Seal Rock, Oregon

A: The short answer is no to both. Most receipts are "thermal" paper, printed via a heat process instead of with old-fashioned ink. The paper requires a fairly large infusion of BPA for the numbers to appear. When it gets recycled with other kinds of paper, it potentially ends up in products like shopping bags—or even toilet paper—which give you a more intimate contact with the chemical than you want. Organizations such as the National Institutes of Health, the Mayo Clinic, and even the American Chemical Society warn that BPA may be harmful, especially to children and developing fetuses.

So it's better to be safe than sorry: Just put your receipts in the regular trash, where the BPA will be more isolated from the environment.

Trashing receipts is not the gravest of sins, since they amount to a tiny fraction of all paper consumed, according to industry sources. But there's a better choice: Opt out of getting a sales receipt in the first place, or ask the clerk to email it to you. Speaking of clerks, they may be in more danger from BPA than the rest of us because they constantly handle thermal paper. By ditching the receipt, you'll do yourself, the planet, and that hardworking sales clerk a favor.