In a major policy change, the head of the Environmental Protection Agency called for a complete phase-out of the use of CFCs and other chemicals linked to depletion of Earth's protective ozone layer. EPA Administrator Lee M. Thomas for the first time said the United States and other nations must go beyond the requirements of the Montreal Protocol, an agreement to reduce industrial emissions believed to be breaking down the ozone layer, which screens out harmful levels of ultraviolet radiation from the sun. The protocol, which goes into effect in January, requires its 45 signatory nations to cut by roughly 50% their use of chlorofluorocarbons, or CFCs, a chemical widely used as a refrigerant, industrial cleaner and in the production of foam. Thomas cited a new report by Ozone Trends Panel, an international group of scientists. He said that using ground-based instruments, the panel found higher levels of stratospheric ozone depletion than previously predicted by computer models.