WALTHAM — A massive fire that destroyed a luxury apartment complex under construction in downtown Waltham early Sunday morning was the second Boston-area blaze in a month to ravage a new project built with an increasingly popular method — using almost entirely wood.
Firefighters from across Greater Boston on Sunday morning battled the ten-alarm inferno at the construction site between Elm and Cooper streets, their efforts hampered by winds. Five buildings in the complex collapsed, explosions ripped the air, and ash and embers rained down on the streets.
Only two minor injuries, sustained by firefighters, were reported.
The Waltham fire comes after a similar apartment building burned in a major fire in the Ashmont section of Dorchester.
In both cases, the buildings were constructed using wood frames, according to Waltham Fire Chief Paul Ciccone — a practice that is increasingly used to save on costs despite growing concerns nationally about fires breaking out during construction of such complexes.
Robert Logan, vice president of the Waltham City Council and former chair of the council’s ordinance and rules committee, expressed concern Sunday about the use of that type of construction.
“It seems to be all the rage these days,” Logan said. “But they seem to burn pretty well.”
Logan called for the state to revaluate the use of wood-frame construction, citing a number of fires across the country that burned down such apartment complexes during construction.
Dozens of projects are under construction in Greater Boston using this method: four or five stories of wood-frame apartments built above a concrete ground floor. The practice has become increasingly popular with developers looking for ways to build relatively affordable housing to balance the high costs of land and labor. It has also grown in popularity since a 2009 change in international building codes allowed for an extra floor to be built in wood-frame buildings, for a total of six.
Fire officials say the buildings are as safe as any other once they’re fully operational — with sheetrock, fire breaks, smoke detectors, and sprinklers installed — but they are vulnerable during construction, when flames can shoot quickly through rooms composed of little more than wood.
That’s what happened June 28 at the Treadmark apartment complex in Ashmont, where fire crews had to back away from the building after intense flames buckled its roof. It appears to be similar to what happened in Waltham on Sunday.
“When something’s under construction, all the necessary fire stops, fire suppressant systems are not in place,” Ciccone said.
Authorities have no indication the Waltham fire was suspicious, according to Ciccone, who said investigators were “not even close” to determining its cause. State Police said in a statement Sunday that they will assist with the investigation. They referred all questions to the state fire marshal, who did not respond to a request for comment.
Lisa Nickerson, a spokeswoman for Callahan Construction Managers, the contractors for the construction site, said in an e-mailed statement that the site had passed an inspection last week with the Waltham Fire Department and City of Waltham. She declined to answer further questions until the company knows more about the fire.
E-mails sent to the development company, Lincoln Cooper Street LLC, were not returned.
Critics of wood-frame construction, including trade groups for the concrete industry, have been pushing for more stringent building codes in the wake of what they describe as a rash of dangerous fires across the country. They argue that the cost savings of building with wood pale next to the fire risk.
“It’s important to keep in mind that these are people’s homes we’re talking about,” said Kevin Lawlor, spokesman for concrete industry trade group Build With Strength. “Residents and those that we rely on to protect us from fire should not have to worry that their welfare is threatened because developers would rather prioritize insignificant cost-savings over resiliency.”
The apartment complex, comprising 264 luxury apartments and 26 affordable units in buildings four or five stories tall, was slated to open next year, according to a website run by Callahan Construction Managers .
The company’s website also said the complex was constructed with wood frames.
In Waltham on Sunday, firefighters from more than a dozen communities helped battle the fire, which broke out around 4 a.m. Waltham firefighters continued spraying water on the site throughout the day to ensure the debris did not reignite, and they plan to remain on site for several days to monitor it.
Ciccone told reporters just before 7 a.m. Sunday that the complex’s five buildings had collapsed and were reduced to a “large pile of debris.”
“We had multiple explosions during the fire,” Ciccone said.
Aayesha Siddiqui, who lives on Gordon Street, a few blocks from the scene, said she awoke soon after the fire started and saw embers had landed on her husband’s car and cracked its windshield.
“There were flaming embers on the cars, on the houses,” she said.
Crews evacuated housing complexes at 48 Pine St. and 190 Moody St., according to officials. Residents at both buildings were able to return to their homes later in the day.
E&T Auto-Body on Elm St. was one of the neighboring businesses that suffered the worst damage.
Wagner Sozi, the owner of the shop, reported that at least 30 cars inside burned in the fire and some of their gas tanks exploded. The shop’s roof collapsed in the fire, he said.
“I never expected this to happen,” Sozi said. “Callahan’s a big company. They’re very good. There’s nothing [bad] we can really say about them.”
None of the neighboring buildings — the Rhino Lounge restaurant and bar or an apartment complex at 48 Pine St. — caught fire, Ciccone said.
One of the complex’s five buildings was near completion, Ciccone said, and so could have had utilities such as gas and electric already hooked up. Smoke detectors and sprinklers had been installed but were not yet operational.
Sean Smyth of the Globe staff contributed to this report. Sara Salinas can be reached at email@example.com. Follow her on Twitter @saracsalinas. Catie Edmondson can be reached at firstname.lastname@example.org. Follow her on Twitter @CatieEdmondson. Tim Logan can be reached at email@example.com. Follow him on Twitter @bytimlogan.