The plasma torch was a Starfleet cutting tool that used a stream of plasma to cut through solid objects.
Although a tool, Lieutenant Malcolm Reed used one to burn eyes and a mouth to a snowman on Archer's Comet, and then stuck it in to serve as a nose.
After a spike from a Romulan mine pinned Lieutenant Reed to the hull of Enterprise NX-01 in 2152, Captain Jonathan Archer carried a plasma torch with him onto the hull and was about to use it to cut through the spike when Reed stopped him, having detected detonation circuits inside the spikes. After the section of the hull they were on was deliberately detached from the rest of the ship, Archer successfully used the plasma torch to cut through the spike, releasing Reed but simultaneously arming the mine, although they managed to contain the detonation.
When the Starfleet starship Enterprise discovered a Xindi-Insectoid shuttlecraft in January 2154, Chales 'Trip' Tucker III had "half a mind to take a plasma torch" to it.
Reed also used a plasma torch to reach a jammed access port on Enterprise's outer hull in February 2154.
In an alternate timeline in 2165, Trip ordered Reed to use a plasma torch to "slice Yerdrin Lek's ship into neat little pieces" as a means of coercing the truth out of him.
In 2154 of the prime universe, a plasma torch was used by a welder who made some structural modifications to a shuttlepod for a journey to Vulcan.
In 2369, Commander William T. Riker had to have treatment for a facial injury sustained during rehersal for a play, Frame of Mind postponed after another crew member entered sickbay after a plasma torch had exploded in his face.
In 2375, the USS Voyager received a distress call from the lost USS Equinox. On a search and rescue mission aboard the Equinox, Ensign Harry Kim had to use a plasma torch to remove debris from a pinned down Noah Lessing.