Sales of compact fluorescent lightbulbs, or CFLs, have doubled in the last year. They’re great energy savers, but there are things you need to know about them.

On rare occasions, the bulb can fail dramatically just before it burns out. It can flash and make noise or smoke. Underwriters Laboratories, which investigates products for safety, says UL-listed CFLs are not a fire hazard. And manufacturers say they are making circuitry changes so that dramatic failures won’t happen in the future.

If your CFL has a dramatic end, Consumer Reports recommends the following steps:

Turn off the power to the bulb.

Let it cool.

Then remove it by grasping from the base and not the glass part of the bulb.

CFLs do contain small amounts of mercury. So if a bulb breaks, follow the guidelines of the Environmental Protection Agency:

Open the windows and leave the room for at least 15 minutes.

On hard floors, do NOT use a vacuum or broom to clean up the broken bulb.

Instead, scoop up the pieces with cardboard, wearing disposable gloves.

Wipe the area clean with damp paper towels.

To remove broken CFL pieces from a rug, use sticky tape.

Place all debris and cleaning materials in two sealed plastic bags.

Used CFLs that are not broken should be recycled. For recycling information, check with your local sanitation department or go online to epa.gov/bulbrecycling.