The Poundstretcher store in Blackwood is being demolished following a blaze in the early hours of Wednesday morning.
South Wales Fire and Rescue Service say the cause of the fire was bins being set alight.
Fire crews were called out at around 2 o'clock this morning.
Officers say refuse bins were on fire and this had spread to the store room at the back of the shop.
Due to safety concerns the High Street was closed and the electricity supply to a number of shops was cut. Structural engineers were called out to assess the safety of the building.
More top news
ITV Wales research shows councils are chasing about £80 million of unpaid council tax. The WLGA have said collection rates are over 97%.
I admit it's not the most cheerful of starts out there this morning, but hang on in there because the sun will show it's face this morning!
Drizzle gives way to more substantial rain which will push in to western areas during the second half of tonight!