About 40 firefighters have been dealing with a major blaze at the fire station in North Berwick.
The alarm was raised when smoke was spotted at about 05:20 on Monday.
One eyewitnesses told BBC Scotland that the roof of the part-time station had been damaged. There were no reports of injuries.
Station Road has been closed while emergency services deal with the situation. Lothian and Borders Police are at the scene along with fire crews.
Lothian and Borders Fires and Rescue Service said the building and two appliances inside it had been badly damaged.
Craig McLaren, who works in the area, said: "I arrived this morning at about 05:20 and saw smoke and thought someone was burning something.
"I went over to investigate and the fire station was on fire. By 05:30, the station was in flames.
"When the flames broke through it was a blaze of fire probably about 50m above the roof, it was ferocious.
"My main worry was there could have been an explosion."
Willie Gibson, who works at Castle Cottage Interiors across the road from the fire station, said the roof of the building had collapsed.
He added: "I noticed something was wrong when I came to work at seven this morning.
"I panicked at first because I thought it was our workshop on fire. There were no flames but there was lots of smoke."
A spokeswoman for the fire and rescue service said: "Firefighters are working very hard to bring the fire at North Berwick's retained station under control.
"There is still heavy smoke coming from the blaze and police are in attendance to assist early morning commuters trying to access the train station, which is at the rear of the fire station."
She said when crews first arrived the station was well alight and they were unable to safely access the building.
The spokeswoman added: "A risk assessment was carried out and as smoke was blowing towards the sea it was deemed safest to leave residents in a nearby housing estate indoors and clear from the worst of the smoke and the cold weather.
"Crews have been working very hard in difficult weather conditions to extinguish the blaze. Fire investigation is on the scene but it is too early to say what caused the fire."
Crews from East Linton, Haddington, Dunbar, Newcraighall, Tranent, an Incident Support Unit from Marionville, a Command Support Unit from Liberton and a height appliance from McDonald Road were all called to the scene.
Continuity plans are being put in place to ensure fire cover in the immediate area.