About 20,000 employees of Mittal Steel USA will take the Energy Star Change a Light Pledge to use energy-efficient lighting in an effort to protect the environment.

The company helped employees fulfill the goal of the campaign by exchanging each pledge for a compact fluorescent light bulb and a fact sheet on the amount of energy that's saved by replacing an incandescent bulb with a CFL.

The Energy Star Change a Light, Change the World Campaign is a national challenge sponsored by Environmental Protection Agency and the US Department of Energy to encourage Americans to switch to light bulbs and fixtures that have earned the Energy Star for energy efficiency.

Mittal conducted the campaign as part of its overall energy-awareness initiative, which seeks to reduce the use of energy in its operations as well as in employees' homes.

Lighting accounts for about 20 per cent of a home's electricity use, and Energy Star touts the switch to energy-efficient lights as a significant way to reduce greenhouse gases, save energy and protect the environment.

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According to EPA estimates, Mittal employees' 20,000 pledges have the potential to save more than 5.5 million kilowatt hours of energy and nearly 9 million pounds of greenhouse gas emissions.

"These are the savings from each employee changing just one bulb," said Larry Fabina, coordinator of the company's energy-conservation initiative.

Mittal Steel USA is a subsidiary of Arcelor-Mittal, the world's leading steel company.

Energy Star was introduced by the EPA in 1992 as a voluntary, market-based partnership to reduce air pollution through increased energy efficiency.