HUDSON, N.Y. - There are two sides to Warren Street, the artery that divides Hudson in more ways than north and south.

On the seven-block strip that runs from the city square to the Hudson River, storefronts boarded up a decade ago have been transformed into antiques shops and cafes that look more like Greenwich Village in New York City than rural upstate New York.

But to the east, where the street turns into Route 9 and enters the town of Greenport, trendy stores give way to rolling hills scarred by quarries and dotted with old barns that need a paint job.

It is here that the remnants of two cement plants rise into view. For most of the last century, they were the community's economic lungs - supplying it with jobs and, as a result, a thriving downtown.

Now, history seems poised to repeat itself.

Along a thin ribbon of asphalt on the city's outskirts, a multinational corporation wants to rip the heart out of Becraft Mountain, one of the richest deposits of limestone in the Northeast, and produce 2 million tons of cement a year in what would be one of the largest cement plants in the nation.

If it gets to build the $320 million coal-fired plant, Montreal-based St. Lawrence Cement says it would shut down a dirtier, century-old facility in Catskill that it has operated since 1984.

Heart of debate

The proposal, first floated in 1998, has deepened the rift along Warren Street, a divide that has emerged largely along income lines and between the "newcomers" of the past decade and the region's longtime residents.

At its core, the argument is over whether the community needs to revive the past to plunge into the future, and whether the economic gains offered by cement production would be worth the costs to the environment, residents' health and the new arts-and-tourism economy.

"It feels like Storm King, which got so many people on so many levels thinking about what this land could be," said Sara Griffen, president of the Olana Partnership, referring to the battle begun in the 1960s that saved a mountain near in the Hudson Highlands from being ravaged by a power plant. It's widely regarded as the genesis of the environmental movement.

Griffen opposes the St. Lawrence project because its 406-foot-high smokestack will sully some of the views from Olana, a state historic site that was the home of the artist Frederic Edwin Church. The air pollution from the plant could destroy the 19th-century mansion's facade, she said.

17 permits needed

A total of 17 permits from the state and federal government are needed for the plant to become reality. So far, health and environmental concerns have bogged down the proposal in an environmental review process that has identified noise, fine particles and visual impacts among eight issues needing deeper analysis.

In the meantime, the federal government, the states of Connecticut and Massachusetts, a coalition of environmental groups, and three dozen local physicians have weighed in, questioning whether the plant is, as the company contends, a state-of-the-art and healthy alternative to its dirty ancestor.

St. Lawrence has filed an appeal with the state, trying to block the harder look that an administrative law judge ordered. But until the company gets a new plant operation, it plans to keep running the Catskill plant, sending many more tons of pollution into the air and sucking millions more gallons of Hudson River water.

Now, the decision on whether the competing views of the plant will be aired in a hearing rests with state Environmental Conservation Commissioner Erin Crotty, head of the agency that three years ago ruled that the facility would have a big enough impact on the environment to warrant a review.

"The end result will be the same plant, with the same controls. We don't see the appeal process serving any real purpose, but to give more time for opinions and to drag it out," said Phillip Lochbrunner, company's vice president of major capital projects, describing what will happen if the hearing goes forward, as opponents want.

Scenic Hudson, one of several advocacy groups participating in the review process, considers it absolutely critical that Crotty uphold the judge's decision. "We feel that this company has not done an adequate analysis to justify the relocation of the facility to Greenport," said Ned Sullivan, executive director of the Poughkeepsie-based group.

The line has been drawn in cement. But clearly, the battle is part of a broader conflict over the quality of the air the cement plant's neighbors will breathe. And the arguments there are both scientific and social.

Air quality critical

Half of the issues that the hearing officer wants to review in depth involve air pollution. Both sides in the controversy are focusing their arguments on air quality, the issue on which the battle could be won or lost.

In an aggressive local advertising and public relations campaign, the company claims that replacing an older plant with a modern one will reduce air pollution overall, a net environmental benefit.

A flier delivered to mailboxes on a recent day read: "No matter how you figure it, the answer is always the same: St. Lawrence Cement's new, replacement plant will mean fewer emissions, cleaner air and a better environment."

There is some doubt about that. The company's own numbers show that the new plant will emit more tons of seven of 13 different pollutants, diminishing air quality miles away from the site. Even some supporters of the new plant find the company's claims questionable.

"They have the advertisement in that paper that it will be cleaner air," said 81-year-old Andrew Wyda, whose family has owned a 65-acre farm for a half-century just south of the Universal Atlas cement plant, which St. Lawrence bought and shut down in 1976. "But how can it be? How can you purify the air?"

For the company, the issue is simple: Thousands of tons of nitrogen oxide, a primary component in smog, and sulfur dioxide, the main component of acid rain, will be cut. These two pollutants have long been the biggest problems for the Northeast.

St. Lawrence concedes that other pollution will increase and potentially lower air quality, but its analysis claims the pollution levels still will fall well below state and federal limits. Even if the plant polluted to the level its permits would allow, Lochbrunner said, "it's not going to affect human health and the environment."

Such claims perplex some independent air-quality experts.

"It's absolutely misleading," said James Schwab, a research professor with the department of atmospheric sciences at the State University of New York at Albany. "On the whole, they probably are going to improve the air. But it is clear that there are pollutants that are much more harmful than others," he said.

Further mistrust also is cast upon the company by its record in New York and elsewhere. Since St. Lawrence took over the Catskill plant, the state Department of Environmental Conservation has fined it $11,000 for two violations related to air pollution controls. Both penalties were suspended by the state after the company came into compliance. But opponents say the company's record is evidence that its numbers shouldn't be trusted now.

If approved, Greenport will replace Catskill as the third cement plant in New York and would be among 119 plants operated in 39 states. Still, the United States doesn't make enough cement to supply demand.

St. Lawrence imports 1.5 million tons of cement a year, said Richard Stoneman, a research analyst who covers the company for Dundee Securities Corp. in Toronto. The new plant would allow St. Lawrence to end its reliance on imports.