Oil from the ruptured well in the Gulf of Mexico is seeping into Lake Pontchartrain north of New Orleans, threatening another environmental disaster for the huge body of water that was rescued from pollution in the 1990s.

The lake rebounded then to once again become a bountiful fishing ground and a popular spot for boating and swimming.

"Even the people involved in the restoration didn't believe it could be restored. It was completely written off. It was thought to be an impossible task," said John Lopez, a scientist with the Lake Pontchartrain Basin Foundation, which led the restoration effort. "It has been a dramatic turnabout."

It is threatened again after a weekend when tar balls and an oil sheen pushed by strong winds from faraway Hurricane Alex slipped past lines of barges that were supposed to block the passes connecting the Gulf of Mexico to the lake.

"Our universe is getting very small," said Pete Gerica, president of the Lake Pontchartrain Fishermen's Association.

The oil could be the second setback in five years. Hurricane Katrina knocked out seafood docks and lakeside restaurants in 2005. The lake's water quality also took a hit when the Army Corps of Engineers drained New Orleans' contaminated floodwaters into the lake.

"So far, this stuff has been offshore for the majority of the population in the southeastern portion of Louisiana," Anne Rheams, executive director of the Lake Pontchartrain Basin Foundation, said of the oil spill. "This is bringing it closer to home."

State authorities closed the lake's eastern reaches to fishing Monday, though most of it remained open. Barges were lined up at bayous and passes to stop the oil from coming in, and cleanup crews Tuesday used nets to collect tar balls from marinas and docks.

They also planned to lay 9,000 feet of special permeable booms, but the lake was too choppy for skimmer vessels to operate.

About 1,700 pounds of oily waste has been collected, said Suzanne Parsons Stymiest, a spokeswoman for St. Tammany Parish.

The amount of oil infiltrating 600-square-mile Lake Pontchartrain (pronounced PAHN-chuh-trayn) appears small so far. And tests on seafood have not turned up any oil contamination, said Brian Lezina, a state biologist. But the pollution is distressing to the many people in Louisiana who have a deep attachment to the lake.

"You won't hear songs about a lot of the marshes in south Louisiana, but you will hear songs about Lake Pontchartrain," Lezina said.

Out in the Gulf, meanwhile, stormy weather kept skimmers from working offshore Tuesday for yet another day and delayed the hookup of a big new ship intended to suck more crude from the gushing blown-out well a mile underwater. Also, the arrival of a Navy blimp intended to hover above the relief effort was delayed until Friday.

Tar balls from the spill also washed up on Texas beaches over the holiday weekend, meaning the disaster now touches all five Gulf Coast states, spanning more than 500 miles of coastline.

Lake Pontchartrain, named for the French count of Pontchartrain during the reign of Louis XIV, is on the northern edge of the city. It is connected to the Gulf of Mexico by two main passes: the Rigolets, a winding passage of about 10 miles, and the Chef Menteur, around nine miles long.

For centuries, it has been a playground, a source of seafood and a backdoor route to New Orleans for invading British troops and hurricane storm surge.

Until the 1970s, its shores were a top destination for city folks who took streetcars and buses to the lake to swim and to dine at restaurants that cooked up the lake's crabs and other seafood. They played in penny arcades and rode the Zephyr roller coaster at the Pontchartrain Beach amusement park.

But pollution shut down the swimming and chased away marine life, and the amusement park closed in the early 1980s.

Slowly, the lake revived. In recent years, sightings of dolphins and manatees have delighted locals, and commercial and recreational fishing is thriving.

Anthony Montalbano Jr., the chef and owner of II Tony's, an Italian seafood restaurant next to the lake, said it has been a struggle to stay open. Katrina swamped his restaurant at Bucktown, a lakeside community in New Orleans that has the feel of a bayou town.

"This was going to be our best year since Katrina for sure, but not now," Montalbano said as the TV in the bar showed an ad for a law firm suing BP.

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Associated Press writers Michael Kunzelman and Tom Breen in New Orleans contributed to this report.