Hackensack, N.J. ? If a light bulb can be hip, compact fluorescents are “it” these days. The corkscrew-shaped bulbs last six times as long as conventional incandescent lights, use 75 percent less electricity and are a simple way to reduce global-warming pollution.

But each bulb also contains a tiny bead of mercury, a toxic metal blamed for poisoning waters and fish around the country. Here’s a primer on how you may handle the problem:

Q. How much mercury is in a bulb?

The average compact fluorescent bulb (CFL) contains 5 milligrams of mercury. When the bulb’s turned on, electricity zaps the liquid, starting a chain reaction that eventually lights your home.

Used properly, CFLs are safe, the Environmental Protection Agency says. But experts worry about the accumulated effect of tossing tens of thousands of bulbs in the trash every year. Mercury can impair neurological development, especially among children, and can also damage the kidneys and liver. Most people are exposed by eating seafood from contaminated waters.

Q. So how do I dispose of a bulb safely?

CFLs are considered hazardous waste, making them costly for towns to handle. Home Depot collects used bulbs from consumers in Canada, but so far the option isn’t available in the United States. It’s expensive for retailers to handle the bulbs, too. The EPA says it’s working with manufacturers and retailers to expand disposal options.

Q. If I break a bulb, am I in danger?

The EPA’s advice if you break a CFL: Open nearby windows to disperse any vapor that may escape, carefully sweep up the fragments (not using your hands) and wipe the area clean with a paper towel. Don’t use a vacuum. The agency recommends placing all fragments in a sealed plastic bag and putting it in the trash.

Q. So what’s so green about CFLs?

The bulbs prevent more mercury pollution than they might cause, the EPA says. Most mercury in the air comes from burning coal to produce energy, and fluorescent bulbs use a lot less energy than traditional lighting. A power plant emits 10 milligrams of mercury to operate an incandescent bulb compared with 2.4 milligrams to run a CFL for the same time, the agency says.