The same researchers found that their original estimates for the burn barrel were high, and that the incineration plant used for comparison represented a theoretical 'clean' plant rather than any existing facility. Their later studies found that burn barrels produced a median of 24.95 nanograms TEQ per lb garbage burned, so that a family burning 5 lbs of trash per day, or 1825 lbs per year, produces a total of 0.0455 mg TEQ per year, and that the equivalent number of burn barrels for the of the 251 municipal waste combustors inventoried by the EPA in the U.S. in 2000, is 1,841,700, or on average, 7337 family burn barrels per municipal waste incinerator.