Plastic #5 - Polypropylene (PP) is a thermoplastic polymer. It is strong, tough, has a high resistance to heat and acts as a barrier to moisture. Most PP are microwavable safe and dishwasher safe. NOTE: microwavable/dishwasher safe only means that the plastic will not warp when heated.
Just so, is it bad to put plastic in the microwave?
If your idea of meal preparation is microwaving leftovers in the plastic takeout container they came in, here's some bad news: Several chemicals in pliable plastic can leach into your food when you heat it, and even if you're diligent enough to transfer the food to a bowl or plate labeled “microwave-safe,” you still
Is it safe to heat plastic in the microwave?
That being said, not all plastic containers are designed to handle the heat of the microwave. To be avoid any risk, only use plastic containers that are labeled as “microwave safe,” and avoid using older containers that have been cracked or scratched because these are more likely to leach plastics into food.