Molina, Mario Jose, muh LEE nuh, MAH ryoh haw SEH (1943-...), a Mexican-born American chemist, contributed to the discovery that artificial substances called chlorofluorocarbons (CFC's) damage the protective ozone layer in the earth's upper atmosphere (see Chlorofluorocarbon). Ozone, a form of oxygen, shields the earth from the sun's ultraviolet radiation, which can harm living things. Molina shared the 1995 Nobel Prize in chemistry with F. Sherwood Rowland of the United States and Paul Crutzen of the Netherlands, who identified different threats to the ozone layer.