Environmentalists are urging the phase-out of two common industrial solvents, methyl chloroform and carbon tetrachloride, that they say are largely unrecognized depleters of Earth's protective ozone layer.

According to the Environmental Policy Institute, the widely used solvents are a greater threat to the ozone layer than even some chlorofluorocarbons, or CFCs, which are the target of an international treaty to cut ozone-killing chlorine in the upper atmosphere."Even a complete phase-out of CFCs will not substantially reduce the total levels of chlorine in the stratosphere without accompanying regulation of these two chemicals," warned a report released by the institute Tuesday.