We were dealing with apparent decomposition product of "immutable" Mirex used in very effective bait for imported fire ant. This process was a big mystery to us all at the time, so I wondered why the Science publication was not referenced: Mirex in the environment: Its degradation to kepone and related compounds Article in Science 194(4268):939-41 · December 1976 DOI: 10.1126/science.62396 · Source: PubMed 1st David Arthur Carlson 50.88 · University of Florida 2nd K D Konyha + 1 3rd W B Wheeler Last R G Zaylskie Show more authors Abstract The chlorocarbon mirex undergoes slow, successive loss of chlorine in the field to a series of related compounds that had lost one or more chlorine atoms. Soil samples were recovered 12 years after treatment at 1 part per million (ppm), and ant bait was recovered 5 years after an aircraft crash. As much as 50 percent of the original mirex was recovered at levels of about 0.5 and 640 ppm, respectively. Kepone was present at levels of 0.02 ppm in soil and 10 ppm in the bait or up to 10 percent of the recovered mirex, as determined by combined techniques of chromatography and mass spectrometry. This constitutes the first observation of the degradation of mirex in nature, and demonstrates a pathway for its eventual disappearance from the environment.