It was Halloween night and Gareth Harris was passing out candy while his children were attending a party across the street.

When the battalion chief for the Lake Valley Fire Protection District heard a knock at his door, he thought he was going to see a young reveler asking for candy. Instead, a child informed him a roof was burning at the home his children were at directly across the street.

"He said, 'trick or treat, there's a fire across the street,'" Harris recalled.

Engines were dispatched, the roof fire was extinguished and no one was hurt. An overheated chimney was the cause of the fire.

With temperatures expected to plummet overnight this week and the cost of utility bills climbing, many Tahoe residents are turning to their fireplaces, wood-burning stoves, and propane and electric space heaters to keep warm.

While many homeowners do the responsible thing and have their fire flumes cleaned once a year, others do not, putting themselves and their families at risk, Harris said.

Flumes should be cleaned annually by a licensed chimney sweeper, Harris said. The reason is because of the build-up of particulate matter and wood oils known as creosote, combustible compounds that have a consistency of black glue.

In winter when fireplaces are used routinely, the creosote builds up and, when hot, can catch fire which can spread to the chimney, which is the main cause of roof fires that are prevalent in Tahoe during winter.

But it's not only fireplaces that can catch fire. Other dangers loom when warming your home, including space heaters. These small appliances can be dangerous, even deadly, if not used properly.

Gerrard Cash, 50, was found dead Oct. 10 in the living room of his Coachland mobile home in Truckee, according to the Nevada County Sheriff's Office. Investigators discovered a propane gas space heater in the home without proper ventilation. Sheriff's Sgt. Frank Koehler said toxicology results revealed the level of carbon monoxide in Cash's blood was .58. A level of .40 is considered to be lethal, he said.

"We are presuming it was an accidental death due to carbon monoxide poisoning," Koehler said.

Koehler said investigators found nothing to indicate foul play or suicide. Every year there are reports of carbon monoxide related deaths, he said, typically occurring because of improper ventilation.

Electric space heaters - such as a ceramic, coil, or an oil-filled radiator heater - are typically purchased by customers to heat a home, Harris said. Kerosene or propane gas space heaters are often found on construction sites because the heaters require proper ventilation.

The use of kerosene heaters inside the home is against the law in California.

Harris said he discourages customers from using propane space heaters for their homes because of the risk of carbon monoxide poisoning. If one does use them they need to be sure there is proper ventilation. Also, Harris advises to get a carbon monoxide detector.