The 20-day U.S. Change a Light Bus Tour concluded Tuesday, with nearly 1 million citizens pledging to change light bulbs to help fight climate change.

The U.S. Environmental Protection Agency and the U.S. Energy Department, which co-sponsored the tour, said if all pledges are fulfilled, people will switch 2.5 million incandescent lights to fluorescent blubs. That, said EPA officials, would represent a potential savings of nearly $70 million in energy costs and prevent 1 billion pounds of greenhouse gas emissions.

EPA Administrator Stephen Johnson participated in the 10-city tour's ending ceremony at New York's Union Square.

"Some have said one person can't change the world," said Johnson. "Well, how about a million people? By teaching nearly a million Americans that protecting the environment and saving money is as easy as changing a light, we are brightening our country's future, one light -- and one person -- at a time."

Critics of the program claim fluorescent bulbs contain small amounts of mercury, a neurotoxin, and might break, possibly contaminating consumers or the soil.

Copyright 2007 by United Press International