On Deadliest Catch things looked pretty grim for the crew of the Saga when toxic smoke started billowing out of the engine room. The smoke sent crew members scurrying as it burned their eyes and caused at least one of them to vomit.
The cause from the smoke turned out to be a burned rubber ring inside of the starboard-side clutch. The clutch helps transfer power to the boats hydraulic system, but in this case the padded ring that keeps the shaft in place disintegrated.
Fortunately they caught the problem just in time, because as the captain said, "[The burning rubber] would have eventually got to the hydraulic oil, erupted in an explosion, and we would all been dead."
Even though it took several hours, the crew was able to replace the clutch and successfully return to fishing.