LOX is not flammable but what?

• A. It is flammable
• B. It is inert
• C. It is explosive
• D. It is not flammable but supports combustion

Answer: (D)

Liquid oxygen acts as an oxidizer. It doesn’t burn by itself, but it makes combustion of other materials happen more readily and with greater intensity because it provides a concentrated supply of oxygen. That’s why the description “not flammable but supports combustion” is the accurate one: LOX is not a fuel, yet it enables and accelerates fires. It isn’t inert; the oxygen-rich environment it creates can cause even normally stable materials to ignite more easily or burn more fiercely. While LOX can contribute to explosive-seeming reactions when fuels are involved under the right conditions, it isn’t an explosive substance on its own. Understanding LOX as an oxidizer explains why it presents serious fire hazards around aviation systems and why safe handling focuses on keeping fuels, oils, and other flammable materials away from oxygen-rich areas.