Crews rushed to the former Playtex site at Devol Industrial Estate on Saturday afternoon after repeated calls to the fire and rescue control room in Johnstone.
Around 20 firefighters from Port Glasgow and Greenock were despatched to the scene in Gareloch Road at 3.30pm and spent three hours tackling the blaze.
The fire started when tyres within the building were set alight.
Port Glasgow watch commander Neil McKechnie said: "There were repeated calls due to smoke issuing from the building.
"When we arrived we were faced with a smoke-logged derelict factory due to the large amount of smoke issuing from several areas of the building."
The watch commander would only confirm that the firefighter is based at Port Glasgow and had hurt his leg.
He said: "He sustained a leg injury - he was injured entering the fire but didn't require hospital treatment."
The senior fire officer says the fire was deliberate and dubbed the culprits behind it 'irresponsible.'
Watch commander McKechnie said: "The actual structure of the building was not damaged - it was a deliberate fire caused by the illegally dumped tyres being set alight."
He added that such vandalism puts lives at risk and wastes resources.
He said: "Because of its severity - the fire was deep-seated - four local appliances were used and meant nearest additional resources had to be located to deal with other emergencies.
"I want to stress the fire safety message - I would just ask people to be aware that when they enter a derelict building and start fires within the buildings, they are very rarely lit.
"If there is build up of of smoke they might find themselves a casualty."
Police, who were alerted and closed Gareloch Road for the duration of the operation, are now investigating the fire.