Q. I have seen that Hawaiian Electric Co. and others are promoting the replacement of old light bulbs with compact fluorescent bulbs. Do they realize that a compact fluorescent bulb has enough mercury in it to contaminate 6,000 gallons of water? I read a report that compact fluorescent light bulbs contaminate the environment with 30,000 pounds of mercury each year.

A. We know that there have been reports circulating about mercury contamination from these bulbs. So we went to the state Health Department for some answers and talked to Steve Chang, who serves as solid and hazardous waste branch chief there.

Chang said the amount of mercury in a compact fluorescent bulb is about 4 milligrams, "or the amount that would fit on the tip of a ballpoint pen."

He said these compact fluorescents are designed to be used in homes and replace incandescent bulbs. Other than the size and shape, he said they are similar to the fluorescent tubes that light up most offices.

"They have about the same mercury in them as a regular 4-foot tube," Chang said. And Chang said traditional electrical power generation — the kind that helps light up those bulbs — ends up as a source of mercury in the environment from burning of fossil fuels, primarily coal.

So, the compact bulbs can reduce mercury another way because they are intended to last five to six years, he said, rather than the year of life of most incandescent bulbs.

He said the compact bulbs reduce energy production because they're more efficient and the producers of electricity can reduce the amount of coal being burned. "We're promoting use; it reduces our dependence on imported fuel."

Q. If there's mercury in those new compact fluorescent bulbs, should I worry about breaking them around my family or how to dispose of them?

A. Chang said the trace amounts of mercury in each bulb would not be considered a safety hazard. "I don't think it's a threat. You just need to be careful when you use the bulbs in your home," he said.

If one breaks, most of the mercury would adhere to the glass, he said, so that amount of mercury wouldn't be a major concern "unless you went and broke every light bulb in your house," he said.

If a fluorescent bulb breaks, Chang suggests taking the precaution of opening windows, airing out the room and sweeping up the shards rather than vacuuming so they can be sealed up in a bag and thrown in the rubbish.

He said some experts have advocated the use of LED lights as a substitute but he said they remain very expensive, with a single 75-watt bulb retailing for about $80. "That's a pretty price to pay for one light bulb," he said.