Microwaving styrofoam, even for a short time like 15-30 seconds, is generally not recommended. Styrofoam is a type of expanded polystyrene foam, and when heated in a microwave, it can release harmful chemicals into your food and the surrounding air.
Styrofoam is not designed to withstand high temperatures, and microwaving it can cause it to melt, warp, or leach potentially toxic substances into your food. The chemicals released from heated styrofoam may include styrene, which is considered a possible human carcinogen, and other volatile organic compounds (VOCs).
To avoid potential health risks and prevent damage to your microwave and food, it's best to avoid microwaving styrofoam altogether. Instead, transfer your food to a microwave-safe container or use a microwave-safe plate or dish for heating.
If you're uncertain about the safety of a particular container in the microwave, check the packaging for "microwave-safe" symbols or warnings. Alternatively, use glass, ceramic, or microwave-safe plastic containers for reheating food in the microwave. Always follow the manufacturer's guidelines for microwave use to ensure your safety and the integrity of your microwave oven.