Walkerite 342 was a gaseous explosive used in fire suppression applications and thermal pulse generation. It could also be used in portable gamma pulse ignition devices, except for those intended for use in high-radiation environments. SFRA 3907A was applicable for all uses of this explosive. In 2367, this explosive was stored on aboard the Federation starship USS Enterprise-D.
In that year, Walkerite 342 was on a list of explosives that Lieutenant Commander Data and Counselor Deanna Troi searched through in an attempt to find one that could produce enough energy to release the USS Enterprise-D and an alien ship from the Tyken's Rift. (TNG: "Night Terrors")