Workmen repairing a roof with a blowtorch sparked major blaze at the iconic Guinness plant in Dublin city centre.
Plumes of thick black smoke billowed across the city skyline as a dozen fire crews battled to bring the inferno under control and stop it from spreading to a nearby ammonia plant.
Two firefighters were taken to hospital after an ammonia blast when a small release of toxic fumes hit them, but their conditions are not life threatening.
Local residents were told to keep their windows and doors closed as the smoke filled the air along the River Liffey.
Motorists were also told to avoid the St James' Gate area as smoke clogged roads and one of the city's Luas tram lines was closed.
Pat Fleming, assistant chief fire officer with Dublin Fire Brigade, said it took three and a half hours to get the inferno under control.
"It was a large scale fire," he said.
It is understood the fire broke out near the Victoria Quay entrance when workmen tried to repair a felt roof with a blow torch and it caught fire shortly after 12pm on Monday.
© Press Association