The fire at the McKechnie Jess plant on Port Glasgow Road, Greenock, was reported just after 3.20am this morning.
About 30 firefighters and six appliances from the Scottish Fire and Rescue Service attended the blaze and were still on-site at the time of publishing. No casualties have been reported.
A spokesperson for Scottish Fire and Rescue said: “Around 30 firefighters are currently tackling a significant fire at a Greenock factory.
“A total of six appliances were mobilised to Port Glasgow Road when the alarm was raised at 3.22am on Wednesday, 8 March.
The fire forced the closure of the A8 in both directions, causing major disruption in the area. Diversions were in place, but HGV drivers were advised not to use them. Disruption on the roads was expected to last until the afternoon.
A Scotland Police spokeswoman told FoodManufacture.co.uk: “Emergency services are currently at the scene and fire fighters are working to contain the fire.
“A joint investigation between police and the fire service will be carried out to establish to circumstances of the fire.”
Investigation will be carried out
The spokeswoman said it was far too early to speculate whether or not the fire was suspicious, as police have been able to access the scene yet.
McKechnie Jess produces a range of meat products for supermarkets and the foodservice industry. It supplies its products to Tesco stores across Scotland.
The blaze set twitter alight, as witnesses captured the conflagration on their mobile phones. See a selection of the best tweets below.
Meanwhile, Lincolnshire Police were investigating the cause of a “suspicious” blaze at an Abbaotoir in Lincolnshire on Friday 24 February.