Halon gas is a chemical compound that is often used in fire suppression systems. While several different types of halon have been developed since this product was first invented, many were dangerous or deadly to humans. Since the late 20th century, two safer types of halon have replaced earlier versions. These include the liquefied type 1211 and type 1301 halon. Both are known by the scientific name bromotrifluoromethane.
Fire requires oxygen, heat and a source of fuel in order to burn. Some early halon gas products would cut off the oxygen supply in a room in order to suppress a fire. While this was an effective way to extinguish a fire, it could also kill any people who were in the room at the time. Newer halon systems simply prevent oxygen from reacting with a fuel source to create a fire, making them much safer for occupants.
The primary benefit to halon gas is its ability to quickly extinguish a fire without damaging items within the room. It is non-conductive, non-volatile, and leaves no residue once the fire has been suppressed. This makes halon a popular choice for computer labs, museums and libraries. It is also an effective choice for protecting electrical equipment, and is often used in boats and airplanes. Halon gas may be used in an overhead fire suppression systems or in a chemical fire extinguisher.
While the two currently used types of halon gas are not generally considered deadly, they can still produce toxic by-products as they work to extinguish a fire. Occupants in a room should exit quickly when a halon system is activated, and should not re-enter until all gas fumes have dissipated. It is also important to recharge the system once it has been activated to ensure continuous protection against fire.
The Montreal Protocol of 1987 established halon gas as an environmental risk, along with many other types of refrigerants and chemicals that are linked to ozone depletion. In accordance with this Protocol, the US Environmental Protection Agency (EPA) banned production of new halon products starting in 1994. Those with existing systems are still permitted to use halon, and existing supplies are carefully monitored to provide for maintenance and refills as needed. All halon must be recycled in accordance with EPA guidelines to minimize adverse effects on the environment. According to the EPA, current supplies are expected to last at least through 2030.