Reactor coolant

Reactor coolant was a hazardous byproduct generated by the warp reactor of some starships in the 22nd century. It produced potentially lethal levels of radiation.

During a simulation in 2153, reactor coolant was shown leaking out of a Malosian cargo shuttle's innards, while Degra and Jonathan Archer were in the simulated shuttle. 

In 2154, Valdore intentionally exposed to reactor coolant on the Romulan drone ship in an effort to coerce Malcolm Reed to reestablish its warp matrix.