Witness have reported four fire engines and some 20 firefighters dealing with an incident at The Barker Partnership accountancy firm on the High Street today, April 24.
The High Street has now been re-opened after crews cordoned off the area.
Local business owner, Kirsty Shepherd, said: "I was at home with my partner who is a Retained Firefighter at Summerbridge when his pager alerted him to respond to an incident at around 7.30am.
"I have a local High Street business, so when I went to it at about 7.45am, I saw that the Summerbridge fire crew including my partner were at the Barker Partnership."
She added: "There are four appliances from what I can see, I can't tell you how many firemen there are, there's quite a lot, I'd say at least 20."
Paul Kendall of Kendall T & Sons butchers said he called the fire service at around 7.15am after the firm's alarm system went off and he could see smoke coming up from the cellar.
Owner of The Oldest Sweet Shop, Keith Tordoff said the building appeared to have mostly just suffered smoke damage, as he could see blackened windows but they were not broken.
But the safety cordon had meant that school children could not be dropped off at their usual spot on the High Street.
Kirsty said: "I went past some of the people from the Barker Partnership, they looked understandably upset and the school kids have had to be dropped off a bit further away because there was no way the bus could get down the High Street."
North Yorkshire Police and North Yorkshire Fire and Rescue have been contacted for more information.