At BEAK, we made many “field observation Firsts”, often soon after a first lab observation. At an 8,500 acre Superfund site in California we did NA investigations on numerous solvent plumes. At a former waste lagoon we made the 1st observation of natural sequential anaerobic-aerobic degradation of TCE and TCA (Cox et al. 1995). We also showed natural cometabolic biodegradation was occurring in the vadose zone due to methane (Cox et al. 1998b). In a 2nd plume with high CF and 1,2-DCA, we showed 1,2-DCA was degrading via vinyl chloride and ethene; CF was being transformed to methylene chloride or removed via cometabolic biodegradation (Cox et al. 1998a). At a landfill in New Hampshire, we made the 1st observation of natural sequential anaerobic-cometabolic degradation of TCE (Cox et al. 1997). Frank Loffler showed dichloropropane (DCP) was reduced to propene in the lab in 1997; two months later we found stoichiometric conversion of DCP to propene at a California landfill (BEAK report).