Flames engulfed the Athens Grill restaurant on East Main Street during dinner rush Friday night, destroying the building and temporarily closing a portion of the busy street.
The restaurant was quickly evacuated and nobody was injured, emergency officials said.
Riverhead firefighters responded to the scene around 8:30 p.m. as smoke was billowing out of the building’s roof, officials said.
The fire was under control before 9:30 p.m. and the building’s electric had been cut. Fire officials said the fire may have spread to the neighboring La Mexicana grocery store.
The grease fire sparked in the kitchen at Athens Grill, a police officer at the scene said.
Riverhead Fire Department press officer Bill Sanok said the damage to the interior of the building was mostly cosmetic but the damage to the roof was more substantial.
The fire spread and was caught between two layers of the roof, which created a challenge for firefighters.
Two Riverhead ladder teams were placed on the roof of the building to extinguish the fire, officials said. Volunteers from the fire departments in Wading River, Flanders, Eastport, Manorville, Westhampton and Hampton Bays all assisted at the scene. The Jamesport Fire Department served as backup at the Riverhead firehouse.
Both Riverhead fire marshals were at the scene investigating the fire Friday night.
As of 10:30 p.m. East Main Street was still closed at Peconic and East avenues. Roanoke Avenue is closed at Second Street.
Athens owner and chef John Mantzopoulos of Greenport said Friday night was the busiest of a summer season that had so far been slow.
“This is the worst thing that could have happened [for the restaurant]” he said. “At least no life was lost.”
His wife, Christine Mantzopoulos, said “No one got hurt and that is the most important thing.”
Ray Pickersgill, president of downtown Riverhead’s Business Improvement District, said he was in the restaurant at the time of the blaze.
“It smelled like burnt toast,” said Mr. Pickersgill, who said the building sustained too much damage and is likely lost.
Tom Lassandro, who was visiting the restaurant with friends at the time the fire sparked, said he initially thought a cook had burned a meal.
“Then the dining room filled with smoke,” he said.
Speaking outside the restaurant, Athens waitress Debra Walsh said, “I can’t believe this is happening.”
Riverhead Town Supervisor Sean Walter said late Friday night that the town will speed up the permit process to rebuild the restaurant as best it can.
“Anything we can do to help we will,” Mr. Walter said.
The fire marks a somber start to a busy weekend on the riverfront with the popular cardboard boat race scheduled for Saturday and a triathlon planned for Sunday.
This is the second downtown restaurant fire in a little more than a week, following a kitchen fire at nearby Cliff’s Rendezvous last Tuesday.
Athens Grill opened in 2004.