There is so little difference in the heat of combustion of the various aircraft hydrocarbon fuels that the severity after ignition would be of no significance from the "fire safety" point of view. The fire-fighting and control measures are the same for the entire group of aviation hydrocarbon fuels. OXYGEN SYSTEMS Oxygen systems on aircraft can present hazardous conditions to fire fighters during an emergency. Liquid oxygen is a light blue liquid that flows like water and is extremely cold. It boils into gaseous oxygen at -297°F (-147°C) and has an expansion rate of approximately 860 to 1. Liquid oxygen is a strong oxidizer, and although it is nonflammable, it vigorously supports combustion. GENERAL HAZARDS During aircraft fire-fighting operations personnel are  constantly  in  harms  way,  from  the  actual fire-fighting operations to the salvage and clean-up operations. All components and material in or on the aircraft are considered hazardous to personnel.  The following text discusses a few of the hazards that personnel need to be familiar with. Anti-icing Fluids Anti-icing fluids are usually a mixture of about 85-percent alcohol and 15-percent glycerin. While not as great as other aircraft hazards, you should remember that alcohol used in aircraft anti-icing systems burns with an almost invisible flame. The best method of control is by dilution with water. Class A Combustibles Class A combustibles in aircraft fires are best extinguished with AFFF. When aircraft cockpit and interior finish materials are burned or charred, they produce toxic gases. These gases include carbon monoxide, hydrogen chloride, and hydrogen cyanide. Therefore, it is necessary that fire-fighting and rescue personnel who enter an aircraft during a fire sequence be equipped with a self-contained breathing apparatus. Ordnance Naval aircraft carry a wide variety of ordnance in support of their assigned missions. For more information on the characteristics and cook-off times of ordnance, refer to chapter 8 of this manual and NATOPS, U.S. Navy Aircraft Firefighting and Rescue Manual,  NAVAIR 00-80R-14, chapter 2. Flare Dispensers The SUU-44/SUU-25 flare dispensers carry eight Mk 45 or LUU-2 paraflares. When the flares are ejected from the dispenser and the tray separates, they must be considered fully armed. Once the tray separates from the flare, it ignites a fuse on the Mk 45 flare, which will fire within 5 to 30 seconds. The LUU-2 flare uses a simple mechanical timer instead of an explosive fuse. If ignited, the Mk 45 or LUU-2 candle should be extinguished by inserting a water applicator tip into the burning end of the candle, applying low-velocity fog. The flare will normally extinguish in less than 30 seconds. If a fog applicator is not readily available, an alternate method is to have a fully outfitted fire fighter cut the shroud lines, pick up the flare by the cold end, jettison it over the side, or remove it to a clear area if ashore. Batteries Alkaline or nickel-cadmium batteries may get hot from internal shorting or thermal runaway. The overheated battery is hazardous to both aircraft and personnel. When an overheated battery is detected, the crash crew should open the battery compartment, check for the following conditions, and take the action indicated: 1. When flame is present, use available extinguishing agent, such as Halon 1211 or CO₂. WARNING Halon  1211  or  CO₂ is  an  acceptable fire-extinguishing agent once a fire has developed. CO₂    must not be directed into a battery compartment to effect cooling or to displace explosive gases. Static electricity generated by the discharge of the extinguisher could explode hydrogen or oxygen gases trapped in the battery compartment. 2. When the battery is emitting smoke, fumes, or electrolyte in the absence of flame or fire, make sure the battery switch in the cockpit is in the OFF position. Remove the quick disconnect from the battery and, if possible, move the battery clear of the aircraft. Use water fog to lower the battery temperature. 12-14