Lexan is a polycarbonate plastic that was created to replace glass where its greater strength justified its higher cost. Lexan is often marketed as "unbreakable" due to is remarkable flexibility and strength. It has recently lost a great deal of popularity due to its BPA content.
Lexan contains "BPAs" or bisphenol A, which may cause some health issues. This has lead to a decrease in the popularity of Lexan for food containers.