Crews from across the county spent hours tackling the fire at the city’s Clifton Moor retail park on Saturday.
Some of the firefighters are reported to have at one stage popped into a nearby McDonald’s while taking a break from their exhausting work at the scene.
They are said to have asked if the restaurant could supply them with free refreshments as they were not carrying any cash.
But their request was reportedly refused, prompting members of the public to step in and buy the firefighters the drinks out of their own pockets.
A spokesman for McDonald’s said this evening: “We value the fantastic work of our emergency services and thank the individuals that dedicate their lives to protecting our local community.
“On this occasion, we would like to apologise to the firefighters who bravely tackled last night’s fire.
“They should have been provided with free refreshments on the night as a small recognition for their efforts.”
An investigation has been launched into the cause of the fire, which left the B&M building a “burnt-out shell”.
Police officers were forced to close roads due to hazardous driving conditions caused by smoke billowing from the scene.
North Yorkshire Police said the fire started in B&M’s storage yard, with 10 engines and two aerial ladder platforms being used to bring it under control. No-one was hurt in the incident.