It is contained within the case of the rocket, into which is pumped a liquid oxidiser called high-test peroxide (HTP), a concentrated form of hydrogen peroxide which is relatively safe to handle.
Alfred Nobel was tasked with figuring out how to stabilise nitroglycerine to make it safe enough to handle, wrote author Burton Feldman in The Nobel Prize : A History of Genius , Controversy and Prestige.
We think they might be getting a wee bit ahead of themselves, though -- we don't yet know how they handle detergent, let alone a quality color-safe bleach.