NEW ORLEANS (AP) — BP made a series of money-saving shortcuts and blunders that dramatically increased the danger of a destructive oil spill in a well that an engineer ominously described as a “nightmare” just six days before the blowout, according to documents released Monday that provide new insight into the causes of the disaster.

The House Energy and Commerce Committee released dozens of internal documents that outline several problems on the deepsea rig in the days and weeks before the April 20 explosion that set in motion the largest environmental disaster in U.S. history. The committee has been investigating the explosion and its aftermath.

“Time after time, it appears that BP made decisions that increased the risk of a blowout to save the company time or expense. If this is what happened, BP’s carelessness and complacency have inflicted a heavy toll on the Gulf, its inhabitants, and the workers on the rig,” said Democratic Reps. Henry A. Waxman and Bart Stupak.

The missteps emerged on the same day that President Barack Obama made his fourth visit to the Gulf, where he sought to assure beleaguered residents that the government will “leave the Gulf Coast in better shape than it was before.”

Obama’s two-day trip to Mississippi, Alabama and Florida represents his latest attempt to persevere through a crisis that has served as an important early test of his presidency. The visit coincides with a national address from the Oval Office on Tuesday night in which he will announce new steps to restore the Gulf Coast ecosystem, according to a senior administration official who spoke on condition of anonymity so as not to upstage the president’s announcements.

“I can’t promise folks … that the oil will be cleaned up overnight. It will not be,” Obama said after encouraging workers in hard hats as they hosed off and repaired oil-blocking boom. “It’s going to be painful for a lot of folks.”

But, he said, “things are going to return to normal.”

The breached well has dumped as much as 114 million gallons of oil into the Gulf under the worst-case scenario described by scientists — a rate of more than 2 million a day. BP has collected 5.6 million gallons of oil through its latest containment cap on top of the well, or about 630,000 gallons per day.

But BP believes it will see considerable improvements in the next two weeks. The company said Monday that it could trap a maximum of roughly 2.2 million gallons of oil each day by the end of June as it deploys additional containment efforts, including a system that could start burning off vast quantities as early as Tuesday. That would more than triple the amount of oil it is currently capturing — and be a huge relief for those trying to keep it from hitting the shore.

“It would be a game changer,” said Coast Guard Chief Petty Officer Mark Boivin, deputy director for near-shore operations at a command center in Mobile. He works with a team that coordinates the efforts of roughly 80 skimming boats gathering oil off the coast.

Still, BP warned its containment efforts could face problems if hoses or pipes clog and engineers struggle to run the complicated collection system. Early efforts at the bottom of the Gulf failed to capture oil.

Meanwhile, congressional investigators have identified several mistakes by BP in the weeks leading up to the disaster as it fell way behind on drilling the well.

BP started drilling in October, only to have the rig damaged by Hurricane Ida a month later. The company switched to the Deepwater Horizon rig and resumed drilling on Feb. 6. The rig was 43 days late for its next drilling location by the time it exploded April 20, costing BP at least $500,000 each day it was overdue, congressional documents show.

As BP found itself in a frantic race against time to get the job done, engineers cut corners in the well design, cementing and drilling mud efforts and the installation of safety devices known as “lockdown sleeves” and “centralizers,” according to congressional investigators.

In the design of the well, the company apparently chose a riskier option among two possibilities to provide a barrier to the flow of gas in space surrounding steel tubes in the well, documents and internal e-mails show. The decision saved BP $7 million to $10 million; the original cost estimate for the well was about $96 million.

In an e-mail, BP engineer Brian Morel told a fellow employee that the company is likely to make last-minute changes in the well.

“We could be running it in 2-3 days, so need a relative quick response. Sorry for the late notice, this has been nightmare well which has everyone all over the place,” Morel wrote.

The e-mail chain culminated with the following message by another worker: “This has been a crazy well for sure.”

BP also apparently rejected advice of a subcontractor, Halliburton Inc., in preparing for a cementing job to close up the well. BP rejected Halliburton’s recommendation to use 21 “centralizers” to make sure the casing ran down the center of the well bore. Instead, BP used six centralizers.

In an e-mail on April 16, a BP official involved in the decision explained: “It will take 10 hours to install them. I do not like this.” Later that day, another official recognized the risks of proceeding with insufficient centralizers but commented: “Who cares, it’s done, end of story, will probably be fine.”

The lawmakers also said BP also decided against a nine- to 12-hour procedure known as a “cement bond log” that would have tested the integrity of the cement. A team from Schlumberger, an oil services firm, was on board the rig, but BP sent the team home on a regularly scheduled helicopter flight the morning of April 20.

Less than 12 hours later, the rig exploded.

BP also failed to fully circulate drilling mud, a 12-hour procedure that could have helped detect gas pockets that later shot up the well and exploded on the drilling rig.

Asked about the details disclosed from the investigation, BP spokesman Mark Proegler said the company’s main focus right now is on the response and stopping the flow of oil. “It would be inappropriate for us to comment while an investigation is ongoing,” Proegler told AP. BP executives including CEO Tony Hayward will be questioned by Congress on Thursday.

The letter from Waxman and Stupak noted at least five questionable decisions BP made before the explosion, and was supplemented by 61 footnotes and dozens of documents.

“The common feature of these five decisions is that they posed a trade-off between cost and well safety,” said Waxman and Stupak. Waxman chairs the energy panel while Stupak heads a subcommittee on oversight and investigations.