An imposing plume of mostly steam is all that remains of a toxic stew of PCBs, oils, solvents, and other waste fed into an incinerator at East Tennessee Technology Park. Since 1991 the facility has burned more than 25 million pounds (11 million kilograms) of waste that, in an earlier era, might have been dumped into trenches and pits (in the ground), where it could have leaked into groundwater. DOE claims that the incinerator meets tough EPA requirements—burning 99.9999 percent of all PCBs.