MSA Safety

Mine Safety Appliances Co. has been manufacturing oxygen breathing apparatus for decades. Their "Chemox" chemical rebreather, primarily designed for use in mines, has been modified for use on Mount Everest in 1952 and 1986. They are stated to be simple in construction and operation. It is essentially a canister of potassium superoxide connected to one-way flow valves to an air bag and thence to the user, as in Rebreathers whose absorbent releases oxygen hereinabove. There are no controls or operable valves of any kind. Breathing rate controls oxygen production. The main disadvantage is the 4-lbs canisters are good for only about 45-minutes of rapid climbing before another canister must be switched in. The canisters supply about 6 hours of sleeping oxygen. ==Hard hats==

MSA also produces protective hard hats. MSA went on to produce a lighter and more streamlined helmet known as the "Topgard" in the 1960s. MSA brand firefighting helmets were notably used by the Los Angeles County Fire Department and were seen regularly on 1970s TV shows. MSA continues to manufacture firefighting protective helmets and in 2000 acquired competitor, Cairns Helmets. == Sites ==

• MSA Corporate Center – Cranberry Township, Pennsylvania • John T. Ryan Memorial Lab – Cranberry Township, Pennsylvania • Murrysville, Pennsylvania – Murrysville, Pennsylvania • Jacksonville, North Carolina – Jacksonville, North Carolina • Lake Forest, California – Lake Forest, California • Toronto, Ontario – Toronto, Ontario • Edmonton, Alberta – Edmonton, Alberta • MSA General Monitors - Galway, Ireland == Notes ==