Wherever is Castle Hospital! I read that there is a doctor there, Edward Fujimoto who said that a combination of high heat, fatty food and plastics will realease dioxin and this of course, is a no-no as dioxin is known to cause cancer, especially breast cancer. So, it follows that one should not use plastic containers or plastic wraps when heating up or cooking food using the microwave. Even without the fat component, one has been advised not to drink water from a plastic bottle that has been left in a car but no water bottles in a freezer? Now, where is the heat component I wonder and will that really cause cancer? Mull over that will you and play safe if you must!