When paper is made, wood pulp is combined with water and then pressed into sheets and dried. In its natural state, paper is brown. However, in many cases, chlorine is used to bleach paper in order to remove imperfections and give paper its white appearance. The traditional bleaching process is extremely harmful to the environment, as it releases toxins such as chlorine and dioxins. Many modern paper plants have switched from chlorine bleaching to the less harmful chlorine dioxide, but even this bleaching process still releases hazardous emissions into our environment.