Less than three hours after firefighters battled stifling temperatures and put out a two-alarm fire in Lower Belvidere last night, they were called to a second two-alarm blaze in the Lower Highlands that left about a dozen people homeless.

Crews responded to 30 Coral St., after someone called 911 and reported flames coming from a building at 9:29 p.m.

The first fire engine at the scene immediately spotted heavy smoke and fire coming from the two-story apartment building at Coral and Grove streets.

No residents were hurt, but a firefighter was wheeled away on a stretcher after he fell while inside the home battling the blaze. His condition was not immediately available, but he remained conscious at the scene and sat up in a stretcher.

Temperatures had reached 99 degrees in Lowell earlier in the day, and it was 87 degrees as many of the same firefighters who had battled an earlier fire at East Merrimack and Nesmith streets responded to this blaze.

Deputy Chief Robert Flynn said the fire started in the home's kitchen. He said a candle may have sparked the blaze, but the cause remains under investigation.

The blaze was under control by about 10 p.m.

Chandra Keo, 52, who lives on the second floor with four other adults, said he was in the shower when he heard there was a fire.

He got out of the shower and tried to put water on the fire in the kitchen, but the effort made little difference so he fled along with his family.

"I grabbed some clothes and ran out," he said. "I don't got nothing."

A man who lives with Keo, who did not give his name, said someone had left a candle burning inside the apartment and then went outside to escape the heat inside.

The man said he saw smoking coming from the building from the street and ran back inside. He threw a bucket of water on the flames but it did no good.

"It didn't help, so we got out," he said.

Crews were still at the scene putting out hot spots late last night.

A volunteer from the Merrimack Valley Chapter of the American Red Cross said the agency was providing assistance to over a dozen people at the scene last night.