After a decades-long battle by residents and officials in Alexandria, the GenOn Power Plant, one of the region's largest producers of air pollution, finally went offline Monday.

The 63-year-old coal-fired power plant along the Potomac River was ultimately shuttered not only because of environmental concerns but for economic reasons: It couldn't compete against cheaper, cleaner power producers.

Still, Rep. Jim Moran, D-Va., called the former Mirant plant's closing "a long-fought but well-won victory" for the city, joining others who fought against the plant's continued operation and hailed its passing.

"Today is something we've worked towards for a very long time," said Elizabeth Chimento, one of two Alexandria residents to first study the health impacts of the plant on the local population. "I think we're all a lot happier now that there's not any pollution in the air."

A Harvard School of Public Health study concluded that the plant, opened in 1949 and producing energy for Pepco, was responsible for about 59 deaths, 66 hospitalizations, 870 emergency room visits and more than 3,000 annual asthma attacks in the area. Opponents also charged that the plant was pumping contaminants across the river to some of the poorest areas of the District, affecting the air, water and health of those outside of Alexandria as well.

Local officials collected similar evidence against the plant each year since 2001, but it wasn't until August 2011 that an agreement was struck that would permanently close the plant. In the deal, the city returned $32 million that was supposed to pay for new pollution controls at the plant to GenOn.

Alexandria Mayor Bill Euille said the plant's closure was "truly a success story" and a model for how cities and residents could work together to rid themselves of harmful businesses.

The city plans to demolish the plant, located at the corner of Bashford Lane and North Royal Street, after conducting environmental studies of the area.

Euille said the site could be for a mix of developments that would expand the city's historic waterfront. No potential developers have been identified, and it could take another five years for the city to fully develop plans for the site, Euille said.