A spokeswoman for the Cheshire Fire Service said that the fire had started on the evening of 15 April, and that flames from the warehouse had been spotted by a passer-by.
The fire was finally brought under control on the morning of 19 April.
At its height some six appliances were in attendance at the Ellesmere Port unit. An investigation into the cause of the fire will now get underway.
Bridgewater Paper safety officer John Pickering said that the matter was an off-site issue, with the full extent of the damage being assessed. He declined to comment further.
Bridgewater Paper is one of the UK's three recycled newsprint mills, with a production capacity of 289,000 tonnes per year of both
standard and coloured newsprint.
Canadian-based Abitibi-Consolidated, one of the world's largest manufacturers of newsprint, owns the company.
