(Adds comments from police briefing)
By Matthieu Belanger
L'ISLE-VERTE, Quebec, Jan 23 (Reuters) - Police will spend Thursday night sifting through the frozen ruins of a wooden, three-story residence for the elderly that burned down in the Eastern Canadian province of Quebec, killing at least three people and leaving 30 more missing.
Fanned by high winds, the early morning fire engulfed an older section of the Residence du Havre in the small community of L'Isle-Verte on the south shore of the St. Lawrence River about 230 km (140 miles) northeast of Quebec City.
The building only had a partial sprinkler system, according to a document filed by the residence. Acting Mayor Ginette Caron said many of the residents had used wheel chairs or walkers, while some had Alzheimer's disease.
Firemen battled for five hours in temperatures as low as minus 22 Celsius (minus 7.6 Fahrenheit) to extinguish the blaze.
The number of dead and missing remained unchanged all day.
"The problem we face now is the weather conditions. To fight the fire, water had to be used, and that water has frozen," Quebec police spokesman Guy Lapointe told a briefing.
Police intend to work carefully, both to stay safe in the extremely difficult conditions and to ensure that the remains of potential victims remain intact, he added.
"In the next few hours, if all goes well, we'll begin to work on scene and, if the lighting we've brought in allows it, the objective is to work through the night," said Lapointe.
Around 20 people were rescued, some of who were taken to hospital. Police said the death toll might not necessarily reach 30, saying some of the missing could be staying elsewhere or traveling with their families.
The fire broke out shortly after midnight (0500 GMT) and was extinguished about five hours later. More than half the residence was burned to the ground.
Eyewitness Pascal Fillion told public broadcaster RDI that at 1 a.m. a large part of the building was already on fire, caused in part to the high winds.
"There was one person we saw, who they wanted to save, but he was on the top floor, and with the fire and the wind they weren't able to come any closer," Fillion said.
Video footage of the blaze showed huge sheets of flame leaping into the air.
According to a document filed with the Quebec health ministry, the residence was home to 52 people, 37 of whom were 85 or older. It had a maximum capacity of 60 people.
Undamaged parts of the building were covered in icicles and thick sheets of ice, testament to temperatures that dropped as low as minus 22 Celsius (minus 7.6 Fahrenheit).
One man described to RDI how his grandmother had called for help from a second-floor balcony and said efforts to reach her by ladder failed.
"She died on the balcony," he said, his voice breaking.
PARTIAL SPRINKLER SYSTEM
The document filed with the Quebec health ministry said the residence had a partial sprinkler system. The residence's website said it had a sprinkler system, but gave no details.
RDI and the Globe and Mail newspaper said Plomberie St-Pie-X Inc, a plumbing company, had installed sprinklers in the newer part of the building when it was renovated in the early 2000s.
"The section that burned was not protected by a sprinkler system," Plomberie St-Pie-X Inc co-owner Etienne Desjardins told RDI. He did not respond to a request for comment.
Reuters was not immediately able to contact Roch Bernier or Irene Plante, listed as the owners of the residence.
Jean-Pierre Ouellet of the FTQ labor union told RDI that regulations for seniors' homes were not strict enough.
Agnes Maltais, labor minister for the provincial Quebec government, said although those rules were gradually being tightened, privately owned seniors' residences were not currently required to install sprinklers.
That could change depending on the eventual results of a probe into Thursday's fire, she told reporters in Quebec City.
The residence's website says the building was built in 1997 and expanded in 2002, and that it had sections for people who were independent and semi-independent, and for those who needed more assistance.
Quebec Premier Pauline Marois said she was "deeply saddened" by the tragedy and sent several government ministers to the site to offer assistance.
Last July, 47 people died when a train carrying crude oil derailed and exploded in the middle of the Quebec town of Lac-Megantic, about 400 km southwest of the site of Thursday's fire.
According to Canadian Press, the worst ever fire in a Canadian nursing home occurred in Notre-Dame-du-Lac, Quebec in 1969, when 54 people died. (Reporting by David Ljunggren and Jeffrey Hodgson; Editing by Frank McGurty, Peter Galloway, Bernard Orr and Andre Grenon)