Experiments were performed in which one ear of each of 36 cats was exposed to a 500‐Hz pure tone for periods totaling 80 min at one of four intensities while cochlear microphonic (CM) measurements were made. Exposure intensities were those necessary to produce a maximum in CM at 500 Hz, or 10 dB, 20 dB, or 30 dB higher than that. CM sensitivity before and after exposure was measured for frequencies from 100 Hz to 20 kHz. Losses were widespread and, at the highest intensity, were maximal at 500 Hz. Losses grew gradually with increasing intensity until somewhere between the two highest intensities the rate of loss became very rapid. The results of the present experiment were similar to those of a previous experiment in which a 5.0‐kHz exposure tone was used [G. R. Price, J. Acoust. Soc. Amer.44, 1541–1545 (1968)]. The implications of the data with respect to damage‐risk criteria were discussed.