It will be shown that the model chemistries usde to calculate the effects of supersonic transports for Climatic Impact Assessment Program (Grobecker et al., 1975) and National Research Council (1975a) studies and of large-scale nuclear exchanges for National Research Council (1975B) studies cause our one-dimensional model to predict ozone depletions in 1963--1964 resulting from NOx injected into the stratosphere by the atmosphere nuclear tests of 1956--1962 larger (4--14% ozone reduction in 1963) than is easily consistent with observation. However, calculations carried out with more recent model chemistries result in ozone reductions that are more easily consistent with observation.