UPPER TOWNSHIP, N.J. A group of environmental advocates marked Earth Day on Tuesday by demonstrating against a plan to convert the B.L. England coal-fired electrical generation plant to gas, saying a new plant was unneeded and would be a new source of pollution.

Jeff Tittel, director of the New Jersey Sierra Club, called the site "ground zero" and "the most important location in New Jersey when it comes to protecting the future of the environment."

Tittel and other speakers described the existing plant, which has been in violation of state and federal emissions regulations for decades, as an example of the kind of fossil fuel-based plants they want to see replaced with renewable energy sources, such as wind or solar power.

In January, the New Jersey Pinelands Commission rejected a waiver sought by South Jersey Gas Co. to build a 22-inch natural gas pipeline to the plant through 15 miles of the Pinelands, including about 10 miles of protected forest.

Tittel, who along with most of the others here Tuesday fought the pipeline proposal, told about 20 people at the demonstration that "we'll never have a more important Earth Day" that this.

Most of the demonstrators wore small signs reading "Pines Not Pipes" and larger signs that read "Environmental Disaster" or "B.L. England No, Solar Yes."

Various speakers asserted that while a gas plant would produce less particulate pollution than the existing plant, which burns bunker oil and rubber tires in addition to coal, a gas plant would generate methane and even finer particulates than coal soot, and would continue to discharge "scalding" cooling water into Great Egg Harbor River, depleting its oxygen.

"On Earth Day, B.L. England needs to retire a dinosaur," said Doug O'Malley, director of Environment New Jersey, as he pointed to the plant's towering stack, which was sending a long, white plume out over the river.

O'Malley noted that the plant, which has been in place since the 1960s, operates only at times of peak demand, and as such is online about 30 or 40 days a year. When fully operational, it generates 447 megawatts of power.

If converted, the gas-fired plant would operate year-round and sell the electricity generated to a 13-state cooperative energy grid.

In 2007, the plant was acquired by Rockland Capital, based in Woodlands, Texas. The company did not respond to a request for comment about the demonstration.

The Christie administration supported the pipeline route, and the state Board of Public Utilities controversially petitioned the Pinelands Commission for a waiver on behalf of South Jersey Gas.

BPU representatives said that the state needed the electrical power the gas plant would generate, and that the pipeline would serve as a needed backup for the residents of Cape May County in the event that the main line serving them was out of commission.

Larry Hajna, spokesman for the New Jersey Department of Environmental Protection, said Tuesday the DEP had endorsed the plant's conversion to gas.

"Natural gas is the cleanest-burning fossil fuel by far," said Hajna, adding that converting the plant would "reduce the emission of nitrogen oxide by 98 percent, and sulfur dioxide by 99 percent."

He also said that the state needed the electricity the plant would generate. "If it shuts down, we would probably have to get the energy we need from coal-powered plants in Pennsylvania or Virginia or out west.

"It's not like you can shut down a power plant," Hajna said, "and demand [for energy] just goes away."

He noted that the Oyster Creek nuclear generating plant, a few miles from B.L. England, is scheduled to shut down in 2019.