Some big retailers are promoting compact fluorescent light bulbs as a way to save energy. But improper disposal of the bulbs creates a hazard, because they contain small amounts of mercury.

Recycling them is about to get easier. Home Depot, the nation’s second-largest retailer, will announce on Tuesday that it will take back old compact fluorescents in all 1,973 of its stores in the United States, creating the nation’s most widespread recycling program for the bulbs.

“We kept hearing from the community that there was a little bit of concern about mercury in the C.F.L.’s,” said Ron Jarvis, Home Depot’s senior vice president for environmental innovation, using the industry abbreviation for the bulbs. “And if the C.F.L.’s were in their house, how could they dispose of them?”

Until now, consumers had to seek out local hazardous waste programs or smaller retail chains willing to collect the bulbs for recycling, like Ikea and True Value. Some consumers have waited for retailers like Wal-Mart to have a designated recycling day. Others bought kits to mail the bulbs to a recycling facility.