HAMPTON - The cause of a three-alarm fire that left 12 people homeless on Christmas Eve is still under investigation, according to Hampton Fire Inspector Jon True.

The building, at 7 F St. at Hampton Beach, required 75 firefighters from 12 towns to douse the blaze.

"Fires can take anywhere from a few hours up to years to find out the cause," True said. "Unfortunately, this one is taking some time."

True said that, while he hasn't yet determined the cause of this fire, he does have tips for people to avoid fires during the holiday season.

"There is an increased chance of problems this time of year, with Christmas lights and candles," True said. "Candles are a big one."

He said people should extinguish candles when they leave the room or go to sleep. He also said people should never leave candles in a window that has shades or curtains, which could catch fire.

The dangers of candles aren't limited to just decorative candles.

"When the power goes out, sometimes people use candles to check a pilot or a kerosene lamp," True said. "You should never, ever do that."

He said Christmas lights are also a big concern at this time of year. Christmas lights are typically marked for indoor use, or for indoor/outdoor use, and people should not put indoor lights outside, according to True.

"One big thing is that they need to be hung right," he said. "They need to be hung with hooks, not staples or push pins. That is dangerous."

True said there is a lot of information about fire safety and prevention at the National Fire Protection Association's Web site, at www.nfpa.org, and he encourages people to check the site if they have questions or concerns, or just to want learn more about fire safety.