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 have found cast iron pans in the trash that were trashed because they were Rusty. Cleaning them, de-rusting them, and reseasoning them but them back into service and they are some of my favorite cast iron.