be automatically dispersed into the fire. a well-known brand of fire grenade was the "red comet", which was variously manufactured with other fire-fighting equipment in the denver, colorado area by the red comet manufacturing company from its founding in 1919 until manufacturing operations were closed in the early 1980s. refrigerants prior to the montreal protocol, large quantities of carbon tetrachloride were used to produce the chlorofluorocarbon refrigerants r-11 (trichlorofluoromethane) and r-12 (dichlorodifluoromethane). however, these refrigerants play a role in ozone depletion and have been phased out. carbon tetrachloride is still used to manufacture less destructive refrigerants. fumigant carbon tetrachloride was widely used as a fumigant to kill insect pests in stored grain. it was employed in a mixture known as 80/20, that was 80% carbon tetrachloride and 20% carbon disulfide. the united states environmental protection agency banned its use in 1985. gallery ccl4 measured by the advanced global atmospheric gases experiment (agage) in the lower atmosphere (troposphere) at stations around the world. abundances are given as pollution free monthly mean mole fractions in parts-per-trillion. hemispheric and global mean concentrations of ccl4 (noaa/esrl). time-series of atmospheric concentrations of ccl4 (walker et al., 2000).