This website uses an automated system to rate products on their environmental friendliness. A variety of criteria are used to come up with these ratings, including the materials used to create a product, its energy requirements, and the chemical releases caused by its manufacturer. The toxic chemical releases and other waste management activities of each product's manufacturer were obtained from the EPA's Toxic Release Inventory. The Environmental Rating System is maintained and created by students of U.C. Berkeley in the Mechanical Engineering department.