In an effort to provide guidelines for law enforcement personnel to protect their hearing, the peak pressure level and signal duration (AandBduration) of eight popular firearms were measured and compared with the requirements of OSHA (1970), CHABA DRC (1968), and EPA levels (1974). Small condenser microphones and a storage oscilloscope were used to record the blast wave signatures from a 9‐mm automatic, 0.357‐cal. Magnum revolver, 0.41‐cal. Magnum revolver, 0.22‐cal. revolver, 0.45‐cal. automatic, 0.44‐cal. Magnum revolver, 12‐gauge shotgun, and 0.22‐cal. rifle. Measurements were made at the ear of the person shooting and at the approximate position of a neighbor at a firing range. Some measurements were also made at a practice firing range. A portable tape recorder was found useful for recording gun signals and measuringBdurations. The peak pressure levels of the signatures of all the firearms tested exceed the OSHA maximum of 140 dB. It was found that in an anechoic environment the noise from five of the handguns exceeded the CHABA DRC (1968), while the noise from all of the firearms tested, except the 0.22‐cal. rifle, exceeded the EPA levels (1974). At a sound‐insulated firing range, the noise from all the firearms tested, except the 0.22‐cal. rifle, exceeded the CHABA DRC (1968), while all the firearms tested exceeded the EPA levels (1974).