thumb|upright=1.2|Reconstructed time-series of atmospheric concentrations of CFC-11 After developing his electron capture detector, in the late 1960s, Lovelock was the first to detect the widespread presence of CFCs in the atmosphere. He found a concentration of 60 parts per trillion of CFC-11 over Ireland and, in a partially self-funded research expedition in 1972, went on to measure the concentration of CFC-11 from the northern hemisphere to the Antarctic aboard the research vessel . He found the gas in each of the 50 air samples that he collected but, not realising that the breakdown of CFCs in the stratosphere would release chlorine that posed a threat to the ozone layer, concluded that the level of CFCs constituted "no conceivable hazard". He later stated that he meant "no conceivable toxic hazard".
thumb|upright=12|reconstructed time-series of atmospheric concentrations of cfc-11 after developing his electron capture detector in the late 1960s lovelock was the first to detect the widespread presence of cfcs in the atmosphere he found a concentration of 60 parts per trillion of cfc-11 over ireland and in a partially self-funded research expedition in 1972 went on to measure the concentration of cfc-11 from the northern hemisphere to the antarctic aboard the research vessel  he found the gas in each of the 50 air samples that he collected but not realising that the breakdown of cfcs in the stratosphere would release chlorine that posed a threat to the ozone layer concluded that the level of cfcs constituted "no conceivable hazard" he later stated that he meant "no conceivable toxic hazard"