Halon Fire Extinguishing Agent
Halon gases are halogenated hydrocarbons used to extinguish fires in areas where water or dry chemical agents are inappropriate such as computer and equipment rooms. Halon is extremely stable, non-corrosive and does not react with water, making it a good material for fire suppression. The most common form of Halon used at UC Davis is Halon 1211. Fire extinguishing agents are numbered to identify the ratio of carbon, fluorine, chlorine, and bromine atoms; for example, Halon 1211 has a ratio of 1:2:1:1 for these elements.
When the detection system in a Halon-protected room is activated, the area should be immediately evacuated. The Halon cylinders discharging the extinguishing agent will fill the room with Halon that chemically interrupts the combustion reaction.
Exposure to Halon 1211 or Halon 1301
The effects of Halon 1211 and Halon 1301 on humans have been studied extensively. Halon 1211 and Halon 1301 are not considered carcinogens or cancer-suspect agents according to state and federal regulatory agencies. However, since Halon is heavier than air it may function as a simple asphyxiant by displacing air in a closed space. High levels of exposure to Halon 1211 or Halon 1301 may result in symptoms including lightheadedness, giddiness, shortness of breath, cardiac irregularity, and unconsciousness. These symptoms are reversible and will disappear if the victim is removed from the area of exposure.
If a Halon system discharges, individuals in the room will experience a chilling sensation, smell an acrid, unpleasant odor, and hear an alarm. If this happens, leave the room, close the door and call 911 to alert the UC Davis Fire Department.
At concentrations in air as low as 2% for Halon 1211 and 5% for Halon 1301 an individual may experience a feeling of intoxication. Individuals with pre-existing cardiac conditions may experience a heightened feeling of intoxication from Halon exposure. The UC Davis Fire Department suggests that departments with Halon systems consider replacing them with alternate extinguishing agents.
The primary emergency first-aid procedure following inhalation is immediate removal of the individual from the area.
Please read the Safety Data Sheet (SDS) for the Halon in your work area and review this information with other employees who work in areas containing Halon extinguishing systems.