The fire service say investigators will be arriving at the scene of this morning's blaze at Blackwood's Pound Stretcher store shortly to begin an investigation into the blaze.
Crews will spend the rest of the day dampening down the building say officers.
More top news
Wayne Pivac praised Scarlets' attacking style as they secured the Guinness PRO12 title with a stunning 46-22 success against Munster.
Scarlets sealed a famous victory at the Aviva Stadium in Dublin with an emphatic 46-22 victory over Munster in the Guiness PRO12 final.
Welsh holiday makers have been caught up in travel chaos after British Airlines cancel all flights from Heathrow and Gatwick.