Here is one more reason to say "no receipt" the next time you buy something: Cash register receipts are loaded with the chemical BPA, which changes the color of the receipt when it's exposed to heat. Instead of installing ink cartridges into registers, this chemical allows stores to print receipts by heating it to transfer the information to the paper. Since many paper receipts end up in our waste recycling stream, it gets made into products like paper napkins, toilet paper and food packaging, which can be a method of transferring the chemical into our bodies. The problem? BPA is linked as a possible endocrine disrupter in human beings, and studies show it can have effects on our reproductive development and other neurological functions. The best solution is to avoid taking receipts whenever possible and to never recycle them with your regular paper recycling.