According to the American Academy of Pediatrics, heating plastics in the microwave, bottle warmer, dish washer, under hot water, or in a hot car can cause the plastic to leak and make their way into your food.
According American Academy of Pediatrics, plastics with recycling codes three, six, and seven should be avoided. Even plastics labeled BPA free should avoid coming into contact with heat.
To keep your family and yourself safe, consider swapping out plastics for glass, silicon, or stainless steel containers.