What happens if the Styrofoam container in which I’m heating my food has melted a bit?

What happens if the Styrofoam container, within which I’m heating my food, has melted a bit? I was microwaving some soup and when it came out, a ring of “melted” Styrofoam, where the grease/oil was floating, appeared. I had a bit of the soup and then got scared. Should I be? Thanks for your attention.

I would not recommend reheating food in Styrofoam (generic name polystyrene) or clamshell type food containers in a microwave oven. Next time heat the soup in a glass or ceramic container or microwave safe cookware. Only use microwave approved containers to cook or reheat food. Plastic storage containers not intended for use in a microwave oven can warp or melt allowing dangerous chemicals to leak into food.

Here is some information from the FDA Plastics and the Microwave.