A $500 million project that New Jersey environmental officials say would radically reduce the air pollution spewing from a South Jersey power plant has drawn only angry boos from environmental groups.

The Department of Environmental Protection's recent issuance of a permit allowing the B.L. England electric generation plant in Cape May County to convert from coal-fired to gas-fired is "a sellout for clean air," the Sierra Club said last week.

"Another nail in the coffin for the Christie administration's denial of carbon pollution," said Doug O'Malley, the director of Environment New Jersey, who called the plant a "fossil fuel dinosaur."

"The plant isn't needed - and it's a terrible location," said the Pinelands Preservation Alliance.

Such blistering talk has irked officials at the DEP, who fired back at their critics.

Converting the 54-year-old plant - which has for decades burned coal, oil, and even rubber tires, pouring lead, arsenic, fine particulates, carbon monoxide, and much more into the air in gross violation of state and federal air quality standards - "will make it a modern, efficient plant," said Frank Steitz, director of DEP's air quality management, "and bring it into the 21st century."

What the DEP views as a glass nearly full appears all but empty, however, to environmentalists.

They allege that New Jersey has all the in-state electric generation it needs, and that a gas-fired plant would produce more harmful greenhouse gases.

"Their [DEP's] justifications for this are highly misleading," said Carleton Montgomery, executive director of the Pinelands Preservation Alliance.

Many speakers at the DEP's permit hearings in May also complained that much of the natural gas used at the converted plant would likely come from the mining process known as fracking, which they allege pollutes groundwater and emits methane, another greenhouse gas.

Steitz said the gas would come from many sources, including Mexico.

Two environmental groups are suing the state to block the estimated $400 million conversion, which B.L. England's owners had hoped to start this year.

In their joint lawsuit filed in January with the Appellate Division, the Sierra Club and Environment New Jersey asserted that the New Jersey Pinelands Commission violated its own bylaws in December when it gave South Jersey Gas permission to run 10 miles of gas pipeline to the plant - part of a 22-mile, $100 million project - through legally protected forest.

Three former governors - Democrats Brendan Byrne and Jim Florio and Republican Christine Todd Whitman - have lent support to the environmental groups' lawsuit.

Russ Arlotta, vice president of RC Cape May Holdings L.L.C., which owns B.L. England, has said the coal-to-gas conversion, will wait until the appeal is resolved.

The converted plant, with a capacity of 447 megawatts, would sell electricity to the 11-state PJM grid, which resells it to utilities.

"They're holding up the process," Steitz said in an interview last week. "They're preventing residents of South Jersey from getting healthier air."

The environmental groups concede that converting the plant to gas-fired will reduce certain hazardous emissions. But they allege that the DEP has greatly exaggerated those numbers in order to win public support for a plant consumers do not need.

DEP is "using [emissions] numbers from 20 years ago" - when the plant was running on all three boilers - to compare the health benefits of the converted plant, said Jeff Tittel, Sierra Club's acerbic executive director.

But Steitz and his DEP colleagues countered that Tittel has greatly exaggerated in news releases the quantity of lead the converted plant would generate. "Those lead numbers" in the permit "are for coal-fired," said Steitz.

"Jeff knows what he's doing," said Bob Considine, DEP's communications director.

Considine also defended the project on grounds that closing the plant, which sits on Little Egg Harbor in Upper Township, would increase the risk of brownouts in South Jersey.

Just who has the upper hand in this feud appears uncertain.

The Appellate Division could rule that the Pinelands Commission's executive director acted improperly when she circumvented her board of directors last year to allow the pipeline, which they had previously rejected.

South Jersey Gas would have to decide whether to seek an alternative route outside protected Pinelands.

In the past South Jersey Gas has said those alternative routes would be prohibitively expensive and more damaging to the environment than its preferred route.

The cost of the pipeline would be borne by the utility's ratepayers and by RC Cape May Holdings.