Dangers of #6 Plastics: Polystyrene

Styrene is a chemical in polystyrene plastics/Styrofoam. Prolonged exposure to styrene has been found to be toxic to the brain and nervous system. In scientific studies performed on animals :( , styrene was shown to be harmful to red blood cells, liver, kidneys and stomach.
Children can be exposed to styrene in food containers, second-hand smoke, car exhaust fumes, contaminated drinking water, and "off-gassing of building materials".
Some household items like floor wax, floor polish, paint, varnish, adhesive, carpet, and metal cleaner also contain styrene fumes.
Before buying or using products like these, it would be wise to read the labels or request a Material Safety Data Sheet (MSDS). Avoid products labeled "poison" or "danger".
Avoid food packaging labeled with a "6" or "PS" (polystyrene). Polystyrene can be made into foam-like containers OR plastic containers. Clear "clam shell" deli conatiners, clear plastic cups, plastic forks, knives, and spoons are usually made of polystyrene. Styrene is prone to leach into hot foods, food with a high fat content, and foods containing alcohol.
Choose foods packaged in glass, paper, metal cans, or cardboard instead of these harmful plastics. Another solution would be to cut off the part of the food that was touching the PS container before eating.

View more information at Children's Environmental Health Coalition.