Pollution
Humain
Environnement
Economique

At around 4:00 p.m., a fire broke out in one of the cooling towers of a starch manufacturing plant. Two employees of a contractor were patching leaks on the roof of the tower. They ground the joints and whitened the structure outside the tower, then welded the plates together. The plastic packings inside the tower were in place. The employees left 30 minutes later. An electrician noticed smoke from the electrical shop. He called the shift manager and sounded the siren. The plant’s first responders doused the inside of the tower to keep the flames from spreading. Firefighters were called in. The plant was evacuated. Three technicians safely shut down the production unit, which had not stopped. The fire was brought under control before the firefighters arrived. The small amount of firewater used was contained and then treated at the plant’s wastewater treatment plant. The wastewater plant was closely monitored for a few days. The packings that were completely burnt were disposed as per the plant’s procedure. The cooling tower was a write-off.

A hot spot created during welding of the plates reached the plastic inner packings, igniting them.

The same operation had been successfully carried out on other cooling towers. The risk analysis had not identified the risk of ignition of the plastic packing during hot-spot work on the metal shells of the towers.

In the future, the packings will be removed whenever hot-spot work is performed on the towers. A procedure for work performed outside confined spaces will be drawn up and a reminder of hot-work permit procedures will be given. The person performing the work will have to carry out a check 15 minutes after completing their work and check the structures with a thermal imaging camera. A fire-hose reel will also be added on the roof near the towers. The operator also plans to raise his employees’ awareness of the hazards of hot-spot work and the risk of flame spread. He also plans to revise his method of organizing emergency-response efforts.