Figure 1. Potentiation of noise-induced hearing loss averaged over three tone frequencies contained in the noise or three tone frequencies above those contained in noise produced by co-administration of different carbon monoxide concentrations. A loss of threshold sensitivity of zero dB corresponds to the effect of exposure to 100 dB octave band noise for eight hours. High frequency: 24, 30, 35 kHz. Mid frequency: 12, 16, 20 kHz. Vertical bars are standard error (SE). Octave band noise at 13.6kHz. 100 dBLn 8 hours.