New London — Firefighters on Thursday morning made quick work of a blaze that began in a second-floor unit of the Thames River Apartments, a troubled complex that residents are in the process of vacating.

According to Lee Erdmann, interim executive director of the New London Housing Authority, a tenant of the affected 40 Crystal Ave. unit had left the apartment about 15 minutes before the fire began.

Erdmann said a resident of the third floor, smelling smoke, pulled the alarm. A property manager checked to ensure the unit was vacant and called 911, too, Erdmann said.

Officials about 11:30 a.m. were working to track down the tenant of the second-floor unit. Firefighters ventilated the building and were checking to see whether the damage extended beyond the single unit.

“This was a great response from the fire department,” Erdmann said.

Fire Marshal Vernon Skau said firefighters found heavy smoke on arrival but quickly quashed the flames. Crews took one resident to Lawrence + Memorial Hospital for smoke inhalation, he said.

As of 12:15 p.m., the investigation into the cause and origin of the blaze was pending.

Residents of the federally subsidized housing complex for low-income families soon will be ordered to vacate the building and will be provided with vouchers to assist with the process of moving. That’s in part because the federal Department of Housing and Urban Development has deemed the Thames River complex obsolete.

Erdmann said some residents already have relocated. He expects many more will do the same in the coming 30 days.

He said he was told the last blaze at the complex happened more than eight years ago, when food on the stove of a unit there caught fire.

l.boyle@theday.com