TEA ignites on contact with air and will ignite and/or decompose on contact with water, and with any other oxidizer.[6] TEA is one of the few substances pyrophoric enough to ignite on contact with cryogenic liquid oxygen. Its easy ignition makes it particularly desirable as a rocket engine ignitor. The SpaceX Falcon 9 heavy-lift rocket uses a triethylaluminium-triethylborane mixture as a first-stage ignitor