After your 8-foot CVS receipt is done living its second life as a winter scarf or wedding veil, you might be inclined to do your part for the environment and toss it in the recycling bin. But, unfortunately, CVS receipts probably aren’t recyclable.

As you may have noticed, most drugstore receipt paper is not your average printer paper—it’s thinner, for one thing, and it also has a glossy finish. Lifehacker reports it’s called thermal paper, and text is printed on it through heat transfer rather than ink. To make that process possible, manufacturers coat the paper in a chemical called bisphenol A, or BPA, which many people consider to be a health concern for humans.

In a nutshell, BPA closely resembles estradiol, a kind of estrogen, and can bind to estrogen receptors in our bodies. That may interfere with energy levels, cell repair, reproduction, and thyroid function. But, there isn’t enough evidence to demonstrate if or how BPA affects us, or how much you can safely be exposed to. Some studies suggest it’s less dangerous than the general public thinks. In the absence of definitive answers, many companies have adopted a “better safe than sorry” attitude and made a concerted effort to stay away from using it in plastics and other products.

For receipts, however, it’s still prevalent, and it might also be difficult to remove during the recycling process. According to Recyclebank, this means traces of BPA could end up in new paper products made from recycled materials. To avoid the risk, recyclers often try to keep it out in the first place.

Recycling rules differ by region, so you can always check with your local program to see if they accept receipts that contain BPA. If they don’t, it might be a good time to opt out of getting printed CVS receipts in the first place—find out how to do that here.

[h/t Lifehacker]