The men were filling casks in a warehouse in The Edrington Group's premises when the incident happened on June 29, 2011.
Glasgow Sheriff Court heard they were on a metal walkway at the top levels of the warehouse using flexible hoses to fill the 450-litre casks with whisky being pumped from steel vats.
One worker felt the hose he was using relax before a jet of whisky suddenly shot up towards a ceiling light fitting, which split, igniting the alcohol and sending flames across the roof.
Both workers ran towards the stairs at the back of the warehouse, activating the fire alarm and prompting the evacuation of the whole site within minutes.
The court heard that thousands of litres of the burning spirit poured down the racked casks and onto the forklift truck until the supplying pump was turned off about 15 minutes later.
An investigation into the incident by the Health and Safety Executive (HSE) found that the central aisle lights should not have been used in a flammable atmosphere and that the filling equipment was not suitable for use to transfer a hazardous substance like alcohol at pressure.
The company admitted health and safety breaches and was fined £40,000.