WATERVILLE — Improper disposal of smoking materials caused a fire that damaged an apartment building at 84 Front St. on Monday afternoon, according to fire officials.

“It was an accidental fire,” said fire Captain Rodney Alderman.

The fire started in an enclosed second-floor sun porch on the south side of the three-story wood-frame apartment building, according to Alderman.

“There was smoke damage to the porch and some smoke damage to the second floor,” he said.

The fire was reported at 2:48 p.m. About 15 firefighters were at the scene. Two Fairfield firefighters covered the Waterville station, according to Alderman. Firefighters left the scene at 4:08 p.m., he said.

Alderman stressed the importance of those reporting fires giving accurate and detailed information to dispatchers. In this case, firefighters were dispatched to what was reported as a fire that occurred on a porch but was out.

“The fire was not out,” he said. “The fire had gone up into the ceiling.”

Waterville police helped at the scene.