Updated at 12:40 p.m. on Nov. 6, 2015

GLEN COVE, N.Y. (CBSNewYork) — From a Superfund site to a glittering waterfront destination — that was the plan for one of Long Island’s most scenic locations.

But that $1 billion plan has changed, and now some residents are rallying against it.

As CBS2’s Carolyn Gusoff reported, the shores of Glen Cove have been an untapped jewel for decades.

“It was supposed to be marina, waterfront restaurants, shops, retail,” said resident Grace Sleyzak.

Now, residents claim they’ve been blindsided by an 11th hour change.

“We never expected a huge monstrosity,” said Sleyzak.

“It’s just too big,” said Amy Peters.

“I think it’s going to be a worst-case scenario,” said Marie Rummo.

New plans for Garvies Point now include two residential towers at 12 stories each, with 1,100 units.

Opponents dubbed it an urban-scaled giant that they fear will tap out roads and services and mar waterfront views for miles.

“It’s completely out of character with what exists here. There is nothing like it on Long Island anywhere,” said Peters.

Size comparisons include massive RXR Plaza in Uniondale, which is home to the project’s developer, who said building up rather than out offers more public green space.

“Use the playground, use the parks, walk along the new boardwalk. There will be a new amphitheater. In scenario, we believe it will be a cultural center and a destination,” said Frank Haftel, vice president of development with RXR.

Glen Cove’s mayor cited years of studios and hearings. He called it a vast improvement compared to decades of crumbling industry.

“This project, I believe, is going to transform Glen Cove. It will bring us baby boomers, young professionals, and we’ll get people in the city with disposable income,” said Mayor Reginald Spinello.

But now a lawsuit has been filed by dozens of residents from Glen Cove, Sea Cliff and Glen Head, 1010 WINS’ Mona Rivera reported.

Sea Cliff’s mayor claims Glen Cove broke a 15-year-old agreement that the waterfront project would be half the size.

“This redevelopment is a regional issue,” said Sea Cliff Mayor Bruce Kennedy. “What they are looking to create is the largest building in Nassau and Suffolk county right on the waterfront.”

With shovels planned to hit the ground this spring, does opposition come 20 years too late? Opponents don’t think so, and they’re lobbying to dump the deal, Gusoff reported.

There are dueling renderings of what the 12-story building would look like. The developer said it’s drawings are not yet complete.