With Prusa nozzle, you can print all plastics! Thermistor version can print everything melting under 300°C - PLA, ABS, PolyCarbonate, Nylon. If you Upgrade the nozzle to use thermocouple there is no temperature limit.
Every part which is in contact with plastic is made out of food safe Stainless Steel. Conventional hot-ends are made out of brass, which may contain lead. All cables use fiber glass insulation instead of Teflon, so you dont have to worry about poisonous fumes.
I love open hardware! All my printers in RepRap project are open, nozzle is too! Source will be released once first retail unit is shipped out the door.