A huge mansion under construction on the East Coast is making waves all the way to the shores of the Great Salt Lake. The house on New York's Long Island is so big, it dwarfs the much publicized home of billionaire Bill Gates. And its secretive owner also owns the Utah plant that is the nation's number one source of toxic air pollution.

Environment Specialist John Hollenhorst traveled to New York and begins a three-part series:

Critics of Utah's Magcorp plant say if Ira Rennert can afford to spend $100 million on his home, why can't he clean up his plant in Utah? Magcorp officials told us today they *can* afford to clean it up, and they're working on it.

Every year, Magcorp gets a dubious honor from E.P.A. 'The Nation's Number One Toxic Air Polluter." Latest output: 65 million pounds of toxic gas a year, mostly chlorine. Critics have been trying for two years to get the company and its secretive owner to the bargaining table.

Chip Ward, from the group Citizens Against Chlorine Contamination, says, "We were trying to use both a carrot and stick approach. It's hard to find carrots when you can't find the rabbit."

On the trail of that mysterious rabbit, we went to the buckle of America's money-belt, Wall Street. Some say Ira Rennert is America's most secretive billionaire.

On Wall Street, Rennert is Mr. Nobody, even though he owns the nation's 51st largest private company, Renco Group.

One veteran observer says, 'No one on Wall Street knows anything about Rennert'. As he put it, 'Rennert flies below everybody's radar.'

His business address is pure prestige: Rockefeller Center. On the 42nd floor there's a sign, a locked door, and no information. We asked for literature or brochures about the company, but were told, "Actually, we're a privately-held organization. And we don't have any annual reports. No brochures. We don't have anything like that."

Occasionally Rennert's picture turns up in connection with a charitable cause. In addition to Magcorp, he owns steel, lead and coal companies. And the company that makes Hummers and Humvees.

But now, suddenly, Rennert is big news in New York. Everybody is talking about the enormous house he's building in the exclusive Hamptons of Long Island.

Journalist and neighbor, Linda Bird Francke, told us, "Well, I think it's horrendous." The property is off-limits to outsiders. But we saw crews working in rain and dense Long Island fog. The mansion, with out-buildings, will be well over 100,000 square feet.

The $100-million behemoth will block Linda Bird Francke's million-dollar view of the ocean.

She says, "It's bigger than Fontainebleu, Versailles, bigger than Saddam Hussein's palaces. I mean it's so outrageous."

Angry neighbors have organized to fight city hall's approval. "It's incomprehensible and outrageous," according to stockbroker Joseph Dilworth.

And that $100-million price tag is a juicy target for Magcorp critics in Utah. Ward explains, "For years Magcorp has said, 'We can't afford to clean up our act'. And now we find that's clearly not so. It's just a matter of Mr. Rennert wanting to spend his money on himself, rather than on cleaning up the air that Magcorp's neighbors and their children have to breathe."

Magcorp says that whole premise is false. Until today they wouldn't return our calls.

But today a top official said, "Mr. Rennert has never constrained our spending on environmental controls."

In fact, Magcorp today revealed tentative plans for a very expensive technological upgrade that's expected to make a dramatic improvement.