HAMPTON — An aura of despair permeated the air Thursday as state and local fire investigators set about the difficult task of determining the cause of a five-alarm fire that destroyed three buildings on Ocean Boulevard on Wednesday.

The blaze, which took 200 firefighters from 23 communities more than four hours to bring under control, gutted the Old Salt Eating and Drinking Place, then spread quickly to an adjacent building housing Lexie’s Pizzaria, Cecile’s Gift Shop and six apartment units.

Aided by a strong westerly wind, the fire then spread to Springfield Motor Lodge, gutting the roof and causing interior damage to The Tibet Store and Underground CDs, two businesses located in the basement level of the building.

In all, seven businesses were ruined and at least 100 people were left unemployed in a disaster that officials are estimating caused as much as $3 million in damage.

As police cordoned off several blocks surrounding the perimeter, a Hampton Beach Fire Department aerial ladder truck hovered over the restaurant as firefighters picked their way through the rubble, stabilizing loose structure beams and digging shovel loads of debris.

"We had another flare-up at about 4 this morning (Thursday) on the roof of the Springfield, so we’re still looking for hot spots and shoring up loose railings to keep these structures from collapsing on their own," said Hampton Fire Chief Hank Lipe.

Lipe said the Old Salt and Cecelia’s were both total losses, and that the Springfield Motor Lodge had sustained severe damage to the third floor and major water and smoke damage on the first and second floors as well as the basement.

"Past experience tells me the Old Salt and Cecelia’s will be razed, there’s just too much damage," he said.

Lipe also said there was no evidence an electrical shortage may have caused the fire.

"The sad thing is all these people did everything they could possibly do to comply with all the safety codes. It’s a shame to see this devastation," he said.

Meanwhile, the state fire marshal’s office brought in an accelerate-sniffing dog to search for clues as to how the fire might have started.

As to whether the buildings will be razed, Hampton Building Inspector Dan Vincent said it’s premature to make that determination.

"There’s so much damage here it’s hard to say, but right now that jurisdiction belongs to the state," he said.