NBC Warning Signals

Warning Signals (Land Force and AB). The basic types of attack warning signals are sound and visual. Personnel should warn others, using one or more of these signals. Personnel give the alarm as soon as an attack or a hazard is detected and use an alarm method that cannot be confused easily with other combat signals or sounds. All who hear or see the alarm must repeat it swiftly throughout their areas and supplement the warning with all available communications capability.

• Vocal. The spoken word is the first way of informing personnel of an NBC hazard or attack. The vocal alarm for any CB hazard or attack is the word gas. The person giving the alarm masks first and then shouts, “Gas!” as loudly as possible. Everyone hearing this alarm immediately masks and then repeats the alarm. The vocal alarm for the arrival of radiological contamination in a unit area is the word fallout. The first individual to detect the arrival of fallout will usually be a radiological monitor operating a radiac meter at the unit command post (CP). When the radiac meter records an increase in dose rate to 1 centigray per hour (cGyph) or higher (or other service-determined threshold), the monitor should immediately alert unit personnel.
• Sound. Sound signals reinforce the vocal alarm to warn of the imminent arrival or the presence of NBC hazards. Sound signals consist of a succession of short signals-such as the rapid and continuous beating on a metal object or anything that produces a loud noise. The warning could be made by a succession of short blasts on a vehicle horn or an interrupted warbling siren sound in situations where vocal alarms or the sound of beating on metal would be lost because of battlefield noise.
• Visual. Standard hand-and-arm signals may be used for NBC hazards. They consist of putting on the protective mask, extending both arms to the side horizontally with doubled fists facing up, and moving the fists rapidly up to the head and back down to the horizontal position.
• Visual/Audiovisual. If the automatic chemical agent alarms (ACAAs) are in operation, detected agents will trigger a visual and auditory alarm unit. The person who sees or hears an alarm signal from the alarm unit immediately masks and augments this signal with a vocal signal. Communications personnel who hear the vocal signal immediately mask and relay the signal over the unit communications nets. Personnel reinforce this signal with other sounds or visual signals.