ABC News' Matt Gutman (@mattgutmanABC) and Seni Tienabeso (@senijr_abc) report:

Myrtle Grove, La. - Less than 24 hours before the environmental "trail of the century" was set to begin, the presiding judge, BP and lawyers representing a coalition of plaintiffs agreed to postpone the start a week in order to allow room for a possible settlement, which is a tricky proposition for the oil giant.

"This is the biggest liability suit in the history of the world," New Orleans environmental litigation attorney Stuart Smith said. "Just writing a check for this is not that easy. The damages are still occurring, and the oil is still washing up on the shores. The challenge for BP to settle now is there are too many moving parts."

MOEX, one of the minority partners in the doomed Deepwater Horizon well, settled out of court with the federal government last week for $90 million, after a $220 million settlement that rig operator Transocean made with the government.

If the case against BP goes to court, the total estimated payout for BP in punitive damages and government fines is predicted to be the tens of billions of dollars.

BP's Deepwater Horizon well exploded April 20, 2010, killing 11 rig workers and spilling nearly 200 millions of gallons of crude into the Gulf of Mexico for 86 days.

Officials from BP and the coalition of plaintiffs' attorneys calling itself the Plaintiffs' Steering Committee would not comment on the details of any possible settlement being negotiated. But they agreed Sunday to postpone the trial for a week to March 5.

Emails released by the federal government show BP apparently knew that its initial estimates of the leak, officially at 42,000 gallons a day, were likely far higher.

The emails apparently show that BP actively tried to hide that information from the Coast Guard. Government data later showed the spill to be a near open-hole situation, with 2.6 million gallons leaking every day.

Some Gulf residents like third generation shrimper Darla Rooks were disappointed., "It's a shame, this way we'll never know the truth, what they really did," noting that a trial would likely uncover secrets BP is trying to bury.

The first witness slated was subpoenaed Bob Bea, a noted Berkeley engineer. The second witness was to be BP America CEO Lamar McKay.

Recent reports show that the vast majority of the oil in the Gulf of Mexico has dissipated. But black syrupy oil continues to mar Louisiana marshes. Looking out over a withered swath of marshland, layered with salt grass and cane, Plaquemines Parish President Billy Nungesser said, "I just can't understand how [BP] can say we have done the best we could, we are not going to clean up anymore. That's unacceptable."

Nungesser took ABC News on a tour of several at risk barrier islands. When the tide recedes in the area, which had been some of the Gulf's most fertile fishing grounds, oil blackens the clay-like marsh land closest to the water on some of the islands.

When oil remnants hit the shore line, it kills the grass, making the land beneath it susceptible to erosion. Nungesser claims the oil is accelerating Louisiana marsh erosion.

"This is happening across the whole bay," Nungesser said. "Whether you got to rake it up, shovel it up or put it in garbage bags. It's happening underneath the surface. It just takes the right wind and tide and [the oil] washes it up the bottom and dumps it in the marsh."

Cat Island, a nesting ground for the pelican - the Louisiana state bird was more than twice the size before the spill. Today it's a single acre and many environmentalist fear by next year it will be gone.