Fire extinguisher in the early 60s and Purple-K being developed by the US Navy in the late 1960s. Manually applied dry agents such as graphite for class D (metal) fires had existed since WWII, but it wasn't until 1949 that Ansul introduced a pressurized extinguisher using an external CO2 cartridge to discharge the agent. Met-L-X (sodium chloride) was the first extinguisher developed in the US, with graphite, copper, and several other types being developed later. In the 1970s, Halon 1211 came over to the United States from Europe where it had been used since the late 40s or early 50s. Halon 1301
Cutting extinguisher smoke diving is reduced. The small size of the access hole also reduces any risk of flashover or backdraft. Flashover is reduced by avoiding the need to open up a large access hole, backdraft by the flow of water through this small hole keeping any flow cooled and directed inwards, towards the fire. Secondary advantages are in gaining rapid access to the seat of the fire, directly through most construction materials and without needing to cause structural damage that may further weaken a structure. The cutting extinguisher technique originates in Sweden, with Cold Cut Systems Svenska AB. Cold Cut Systems