Crocs are made of a proprietary closed-cell resin known as Croslite, which is primarily composed of polyethylene vinyl acetate (PEVA), a type of polymer made from fossil fuels. Croslite is an injection-molded EVA foam that forms itself to the wearers feet and offers purported medical benefits, according to some podiatrists. Crocs are not made of rubber, but they are considered a type of plastic. The closed-cell properties of Croslite resist odor, inhibit bacterial and fungal growth, and are non-toxic. Crocs are lightweight, extremely comfortable, and easy to clean with just soap and water. However, the environmental impact of Crocs is a concern, as they are made of chemicals that contain elements of plastic, which is harmful to the environment.