As candles have become a staple of home decor, the number of household fires blamed on them has taken off as well, U.S. statistics show.

In 2001, candles spurred fires in 18,000 U.S. homes, triple the number in 1990, according to the National Fire Protection Association (NFPA). This reverses a decline in candle-related fires during the 1980s.

At the core of the increase is the growing popularity of candles, as the majority of U.S. homes are now adorned with them, according to the NFPA. But it’s the improper use that actually ignites fires.

In 2001, one third of candle-sparked fires happened when lit candles were left unattended or improperly controlled, and one quarter began when a flame came too close to flammable materials, such as holiday decorations.

The NFPA also notes that poverty may play a role in some candle-triggered fires; up to one third of people who died in such fires were using candles because their power had been shut off.

Of the 190 people killed in candle-related fires in 2001, nearly half were children or teenagers. Some fires, close to 6 percent of the overall number, were started by a child who was playing with a candle.

According to the NFPA, some simple measures could have prevented many of these fires. It advises people to never leave a lit candle unattended or near curtains, decorations or anything else combustible. Candles should always be placed on sturdy furniture that won’t be knocked over by children or pets, and in a holder that won’t tip over and is large enough to collect dripping wax.

The organization also cautions against letting children and teens have candles in their bedrooms. Forty percent of candle-related fires, it says, start in the bedroom.