Firefighters were called to the scene after two substances were accidentally mixed together during the decanting process and chlorine gas was produced.
Around 30 firefighters dealt with the incident at Clynelish Distillery in Brora, Sutherland, at around 6.55pm yesterday.
One man who was in the area at the time and was exposed to the gas was taken to hospital suffering from breathing difficulties.
He was kept at Raigmore Hospital in Inverness overnight for observation, the Scottish Fire and Rescue Service (SFRS) said.
SFRS group manager John MacDonald said: "This was an incident with potentially serious outcomes, but due to the quick thinking of on-site staff at the distillery and the response from the emergency services, the incident was dealt with quickly and effectively.
"We are pleased that no-one has been seriously injured and that we managed to help bring the incident to a successful conclusion."
Fire crews from Inverness, Golspie, Helmsdale and Invergordon were sent to the scene.
Firefighters in gas tight suits and breathing apparatus, with support from the SFRS's National Hazmat Technical Support Team, isolated the tank and made the area safe before a specialist clean-up company arrived.
Crews then entered a portable decontamination unit as a precautionary measure.
None of the firefighters were exposed to the gas.