LOUISIANA, United States – AN oil spill that was previously a problem for coastal Louisiana was trickling deeper inland yesterday and toward the shores of New Orleans.

Oil sheen and tar balls from the Deepwater Horizon gusher have been spotted in Lake Pontchartrain, the huge lake forming the northern boundary of the city that was rescued in the 1990s from rampant pollution.

The oil’s spread deeper into Louisiana came the same day that tar balls from the spill were confirmed on a beach in Texas. There’s a question of whether five gallons (19 litres) of the stuff came naturally on the currents or was dragged by a passing ship from elsewhere, but crews combed the beach and pledged to collect the damages from BP.

Meanwhile out in the Gulf, stormy conditions have delayed the hook-up of a new containment vessel, the Helix Producer, to the cap collecting oil from the gushing well head on the seafloor. Officials had originally hoped to connect it today. A new target date hasn’t been announced.

The weather also delayed the arrival of a Navy airship that will serve as a floating observation post above the Gulf. It is now expected to arrive in Mobile, Alabama, on Friday.

The spill’s Joint Incident Command announced Monday that sheen and tar balls had been spotted in the Rigolets, one of the waterways connecting the lake to the Gulf, and in parts of the 630-square-mile (1,630-square-kilometre) lake itself.

Crews placed boom at a natural choke point with hopes of stopping more from entering the lake. Nineteen skimmers and four containment vessels were sent to the affected areas. As of 7:30 pm Monday, they had collected half a tonne of tar balls and waste.

The main part of the lake remained open to fishing, but a chunk southeast of an old car bridge across the lake was closed.

Oil spilling from the BP well would be the most significant environmental challenge since a massive recovery effort lifted Lake Pontchartrain from near death by pollution.

The lake had been a playground for boating and fishing for many decades, until urban run-off and dredging chased away many species by the 1970s. Swimmers were warned of high counts of bacteria. After years of efforts by lake boosters, pollution was stemmed by new regulations and dredging was halted.

The oil could have been pushed deeper into southeastern Louisiana by the tropical weather that began last week with the far-off Hurricane Alex and continued into this week with a low-level tropical system that brought high winds and heavy rain to the state.

The weather has essentially stopped offshore skimming off Mississippi, Alabama and Florida, and curtailed it off Louisiana.

Skimming across the Gulf has scooped up about 23.5 million gallons (89 million litres) of oil-fouled water so far, but officials say it’s impossible to know how much crude could have been sucked up in good weather because of the fluctuating number of boats and other variables.

The oil’s arrival in Texas was predicted Friday by an analysis from the National Oceanic and Atmospheric Administration, which gave a 40 per cent chance of crude reaching the area.

“It was just a matter of time that some of the oil would find its way to Texas,” said Hans Graber, a marine physicist at the University of Miami and co-director of the Center for Southeastern Tropical Advanced Remote Sensing.

About five gallons of tar balls were found Saturday on the Bolivar Peninsula, northeast of Galveston, said Capt Marcus Woodring, the Coast Guard commander for the Houston/Galveston sector. Two gallons (7 1/2 litres) were found Sunday on the peninsula and Galveston Island, though tests have not yet confirmed the oil’s origin.

Woodring said the consistency of the tar balls indicates they could have been spread to Texas water by ships that have worked out in the spill. But there’s no way to confirm how they got there.

Galveston Mayor Joe Jaworski said he believed the tar balls were a fluke, rather than a sign of what’s to come.

“This is good news,” he said. “The water looks good. We’re cautiously optimistic, this is an anomaly.”