Cooking with any plastic is a dubious enterprise, because heat encourages potentially harmful plastic compounds to migrate out of the polymers and potentially into the food. But, as Andrew Turner, a biochemist at the University of Plymouth recently told me, black plastic is particularly crucial to avoid.
In 2018, Turner published one of the earliest papers positing that black plastic products were likely regularly being made from recycled electronic waste. The clue was the plastic’s concerning levels of flame retardants. In some cases, the mix of chemicals matched the profile of those commonly found in computer and television housing, many of which are treated with flame retardants to prevent them from catching fire.
I had this happen when I made a tomato-based dish in a cast iron pan, covered it with foil, and then stored it in the fridge. The aluminum was electroplated to the top of the food, and the pan had iron pits in the bottom.
Yes, I know I was bad for doing that to a cast iron pan. I was young and foolish.
I don’t blame you, very few people know this and it’s not intuitive. With plastic items, everyone learns early that they don’t take heat well. Arguably, it’s not much of a problem anymore since every metal container and silverware is stainless steel and basically only aluminum foil remains. At least now you know why coins make that smell in a sweaty hand.