Buildings in downtown Franklin were evacuated for almost 24 hours after the smell of gasoline filled parts of Central Street. The evacuation ended at 3 p.m. Thursday but the cause of the problem has not been announced.

At least four people spent Wednesday night at the town community center after commercial and residential buildings in the 300 and 400 block of Center Street were evacuated as a safety precaution.

“We gave them a nice space. We’re trying to make it as comfortable for them as possible,” said Chloe Soctak, Franklin’s Parks and Recreation supervisor.

Police and fire officials ordered the evacuation Wednesday evening, including restaurants that were open during dinner hours as well as a number of apartments and condominiums on floors above retail sites. Much of Central Street was partially blocked by fire equipment during the day.

Two gas stations are located on Central Street near the affected area.

Emergency officials spent much of Thursday monitoring vapor levels in and around the affected buildings, including in sewer lines.

“It’s looking at oxygen level content in the air. It’s looking for parts per million of carbon monoxide. And it’s also looking for something called hydrogen sulfide,” firefighter Mike Dery explained of the air monitoring devices.

Fire Chief Michael Foss said none of the concentrations of vapor encountered have been high enough to be flammable or explosive, but said the vapor can collect in small areas and be hazardous.

“The biggest concern is the vapors, how far and where those vapors are going to travel in the next hours, day, weeks,” he said. “They are going to different random locations like cracks in foundations, dirt, air pockets.”

Even though the area was reopened, he urged residents to report any odors.

“In certain locations, we have found gasoline vapors in residential and commercial units,” he said. “If people smell the strong odor of gasoline within a building, they should call 911.”

One business that was affected was 93-year-old Grevior Furniture, a fourth-generation business on Central Street that was expecting a large shipment of furniture Thursday morning in preparation for the Christmas season. A firefighter stayed at the scene to monitor fumes while the work was done.

“The fire department and everybody involved has been absolutely wonderful,” said owner Jason Grevior. “They give us a guy with a monitor … I had my guys here ready to unload, dump it on the street, get out the street as fast as possible, get the truck out of here, get it in the warehouse as fast as we can.”

Grevior pointed to many improvements made to Franklin’s downtown in recent years and lamented the effect this leak might have on the city’s reputation.

“Franklin has been transforming itself. I hope this is just a small band-aid on an easy problem, and we take care of it as fast as possible so we can get back to business,” he said.