Naturally occurring bacteria may be a future solution for myriad pollution problems, mounting laboratory evidence suggests. Last month, USGS scientists reported in Nature that microbes living in oxygen-free sediments can break down derivatives of hydrofluorocarbons, which are among the compounds under consideration to replace ozone-destroying chlorofluorocarbons (CFCs). And now, another USGS scientist reports in the July 14 Nature that microbes which degrade toxic and carcinogenic aromatic hydrocarbons like benzene and toluene can be boosted with an iron additive or chemical binder to work in anaerobic conditions that are commonly found in heavily polluted aquifers. Previously, scientists thought the bacteria could reduce the hard pollutants only if plenty of dissolved oxygen was in the water. Other bacteria have been shown to convert uranium to a highly insoluble form in cbntaminated waters as well.