what kind of plastic is a bike helmet made of
Helmets are largely made of plastics, but the good news is that most of the plastics used are probably safe. Helmet shells may be made of the type of plastic now suspected of leaching out the chemical BPA. High-end helmet shells are often made from polycarbonate (GE's Lexan for example). It has been associated with high quality helmets for more than 20 years, particularly those that are molded in the shell.