In a study of the six top-selling automakers in the United States by the Ecology Center, Toyota scored highest for their use of safe, recyclable plastics in their vehicles. But something tells me this test should have been graded on a curve, as General Motors, Ford, DaimlerChrysler, Honda, and Nissan all earned D's or D-pluses, while Toyota's high mark was nothing to go out and brag about, with the Japanese manufacturer only earning a grade of C. The study revealed that all six manufacturers are still heavily reliant on petrochemical-based plastics, which often release toxic chemicals and are difficult to recycle, and that many foreign manufacturers make better use of sustainable plastics because of tighter recycling requirements.