In 1961, engineers completed an 85-mile section of dike around Lake Okeechobee, and the public was assured it could rest easy — there would be no more disasters like the two 1920s hurricanes that swamped the lake and killed thousands of people.

"This dike has cured the bad habit of tropical hurricanes of using this lake as a weapon of destruction," 86-year-old former President Herbert Hoover said at the ceremony dedicating the first portion of the 143-mile Herbert Hoover Dike.

Today, the fear is back.

The dike is in a state of disrepair, and engineers are laboring to fix the aging earthen wall in a huge, decades-long project that began in December.

The anxiety has been stoked in part by what Hurricane Katrina did to New Orleans last year. But the repair project took on even more urgency in May, when a state-hired panel of experts issued a study that found the dike bears "a striking resemblance to Swiss cheese" and is in imminent danger of failing in another major hurricane — a catastrophe that could threaten as many as 60,000 residents.

Lake Okeechobee sits in the heart of Florida's Everglades and is surrounded by some of the richest farming soil in the state. At 730 square miles, it is the second-largest freshwater lake in the contiguous United States. Dike construction began in 1932, and by 1970 the corps had reinforced the entire shoreline with muck, sand and shell fragments piled up to 35 feet high.

The new job of shoring up the dike could take 25 years at a cost of more $300 million, said the Army Corps' Steve Duba, chief engineer in charge of the project.

"It's 75 years old. It's got problems. It's got a history of seepage," Duba said. "It wasn't built anything close to current design standards."

Still, the corps insists the dike will hold in a hurricane. Water is pumped out to lower the lake level ahead of an approaching storm, reducing pressure on the wall. Moreover, earlier this month the lake was at less than 12.5 feet — its lowest level in about four years, and well below the 17 feet at which the study suggested the dike is in danger of falling.

In some places, the corps will simply replace flood gates and culverts, while in other sections the dike will be practically dismantled and rebuilt.

The first portion of the project involves a 22 1/2-mile segment near the farming town of Pahokee, where about 5,000 people live. Engineers were working to sink a wall made of a concrete mixture 36 feet deep and two feet thick, but the project was recently halted after officials encountered problems with sand and soil filling the trench. It is unclear when work will resume.

The project brings little solace to some who live in the dike's shadow.

Larry Wright, 58, has lived in Pahokee nearly all his life and was there when Hoover proclaimed the dike "proof of alertness."

"They dedicated it as this fantastic new thing. I remember being amazed," Wright recalled. "What's on most people's minds much more now is how the heck are they going to get all of us out of here if it does breach."

About 10 miles south along the lake in Belle Glade, Mayor Ray Sanchez is also nervous. "We just want them to get the work done as quick as possible," he said. "We're in hurricane season now, so we're worried."

However, not everyone is concerned.

"I am in no way in panic mode," said Pahokee Mayor J.P. Sasser. "The absolute strongest structure out here in the Glades is the Herbert Hoover levee. By the time that 100-year storm comes and the conditions exist for it to breach, there won't be any communities left to flood. We would have blown long, long away."

A 1926 hurricane killed more than 4,200 people in Florida, Mississippi and Alabama. Many of Florida's dead lived along Lake Okeechobee, which overflowed. An estimated 2,500 people were killed in Florida in a 1928 hurricane when the lake again broke its banks.

The recent study said a major failure of the dike could irreversibly damage the Everglades, contaminate South Florida's drinking water supply for millions of people, flood thousands of acres of farmland, cost millions in lost production and threaten up to 60,000 residents. People living nearby could see a huge wall of water sweep through their homes if a breach were to occur at the same time as a storm surge.

Because of the flat terrain, the water would probably spread quickly over miles of land, covering it perhaps chest high in places.

The Army Corps' Duba said such a scenario is impossible: "This cannot happen. It's like an apocalypse."

"But that's what we have to plan for," added Charles Tear, Palm Beach County's emergency management chief.