The roof of United Central Bakeries (UCB), based at the Whitehill Industrial Estate in Bathgate, collapsed as flames ripped through the building.
Burning naan bread on the production line set fire to a conveyor belt taking the produce from the oven to a packing area, leaving a third of the plant in ruins in November 2006.
Finsbury Food Group, which owns the firm, spent £5m to refurbish the wrecked factory, which also produces bread and Yum Yums.
Now UCB is suing two firms it blames for the installation of the “thermoplastic” conveyor belt after alleging the parties were “negligent” for failing to ensure the equipment was suitable for naan bread production.
The action has been taken against Spooner Industries Ltd, which designed and fitted the conveyor, and belt provider Forbo Siegling (UK) Ltd.
At a recent hearing, the Court of Session in Edinburgh heard that the bakery cooks dough sprayed with rapeseed oil in an oven at 450C, with the finished portions of naan sometimes emerging on fire.
The UCB factory suffered a blaze sparked by naan bread in 2001 and installed a fire suppression system as a result.
In 2003, the firm hired Spooner Industries to supply and fit a helical conveyor – known as a heliveyor – in a bid to reduce wastage by transporting naan from the oven.
But following another fire in 2003, the damaged conveyor belt was replaced, but fears had grown among UCB managers that it was not properly fire-proof and would “ignite on contact with burning naan bread”. They even used a blowtorch to show that a piece of the belting could be ignited.
In an email on June 23, 2004, UCB managing director Archy Cunningham wrote to Sandy Grieve, of Spooner, and Dennis Jackson, of Forbo, saying: “Am really not happy with the supplier of this belt. The belt should be impossible to set fire to with burning naan bread.”
In a letter, Mr Jackson said that a temperature of 164C would be needed to melt the belt and said it was “very unlikely” a naan bread could achieve this. He added that UCB’s tests with a blowtorch were not relevant as it would reach far hotter levels.
Night shift workers were evacuated after the 2006 fire.
Two firefighters managed to escape unhurt when part of the roof collapsed.
In the court action, UCB allege that the firms were under a duty to advise that the belt material was unsuitable. They are seeking £6,788,556 in damages suffered by rebuilding the factory, replacing machinery and in lost business.
Lord Hodge continued the case for a further hearing.
No-one from United Central Bakeries, Spooner Industries or Forbo Siegling (UK) Ltd was able to comment on the ongoing legal action.