Millions of gallons of oil have leaked into the Gulf of Mexico from a blown-out well at the site of the Deepwater Horizon, which exploded on April 20 and sank two days later.
Federal officials say they plan to investigate every possible cause of last week's massive explosion on the Deepwater Horizon oil rig in the Gulf of Mexico -- including the possibility of criminal acts or negligence.
In the aftermath of the blast, an uncapped underwater oil well continues to leak an estimated 200,000 gallons of oil into the Gulf every day -- creating a monstrous oil slick that made landfall in Louisiana's wetlands Thursday night and could become the nation's worst environmental disaster in decades.
President Obama said Friday that his administration is doing "everything possible" to respond to the explosion of the BP PLC-operated rig.
A top adviser to Obama -- who last month lifted a drilling moratorium for many offshore areas, including the Atlantic Ocean and Gulf of Mexico -- said no new drilling will be authorized until the cause of the explosion, which killed 11 people, is determined. Obama also ordered Interior Secretary Ken Salazar to report within 30 days on what new technologies will be needed to prevent future oil spills.
The Department of Homeland Security and the Department of the Interior are conducting a joint investigation into the explosion. "Investigations are ongoing and everything will be examined," a DOI official told FoxNews.com in an e-mail Friday when asked if any evidence points to acts of criminality or negligence. "It's obviously too early to know."
Salazar has ordered immediate inspections of all 30 deep-water drilling rigs and 47 platforms in the Gulf of Mexico.
"This operation is underway and will be targeted inspections ensuring that [blowout preventer] tests have been completed and those records are available for inspection," the e-mail continued. "We are also verifying that emergency well control exercises are taking place. [U.S. Minerals Management Services] inspectors should complete these inspections within seven days. Once drilling rig inspections are complete, we will start immediately on inspecting all deep-water production platforms."
Along with Homeland Security Secretary Janet Napolitano and Environmental Protection Agency Administrator Lisa Jackson, Salazar was traveling to the Gulf Coast on Friday to inspect ongoing operations and to evaluate the environmental impact of the April 20 explosion.
The officials will conduct an aerial tour of the affected area and meet with federal, state and local officials leading the response effort.
DHS officials declined to comment on the cause of the blast and referred to DOI's statement.
But Elmer Danenberger, who retired in January as the head of offshore regulatory affairs for the U.S. Minerals Management Service, said the investigation into one of the biggest oil spills in U.S. history will center around what happened just before the blast, as workers finished pumping cement between the well pipe and a hole bored into the ocean floor. The process is intended to prevent oil and natural gas from escaping, he said.
"That's what [investigators] said the operation was just prior to the blast," Danenberger said. "Now, how much prior we don't know. Investigators will be all over those issues."
Danenberger said it appears "to be the consensus" among drilling experts that a poor cementing job probably led to the blowout -- when oil and natural gas exit a well with extreme force.
"They're going to be focusing on the root cause, how the oil and gas were able to enter the [well] that should've been secured," he said. "That will be the primary focus, how the influx got in to the [well]."
Cementing operations could benefit from additional inspection standards, Danenberger said, adding that cementing incidents remain too common.
According to a 2007 study by three U.S. Minerals Management Service officials, cementing was a factor in 18 of 39 well blowouts in the Gulf during a 14-year period, making it the single largest factor, the Wall Street Journal reported. Equipment failure and pipe failure were the next leading factors.
"There has been a history of gas influxes during cementing operations, so that is an area of concern, but nothing is confirmed," Danenberger said. "But perhaps additional standards are necessary for cementing operations."
Meanwhile, critics of British Petroleum say that cost-cutting measures by the London-based oil giant helped to contribute to the rig explosion.
Tom Bower, author of the 2009 book "The Squeeze, Oil, Money and Greed in the 21st Century," told Fox News that British Petroleum's economizing led to a lack of engineers, an overdependence on outsourcing and a lack of supervisors to keep an eye on subcontractors.
Transocean Ltd., which operated the rig on lease from BP, has said Halliburton Co. had finished cementing the 18,000-foot well shortly before the explosion. BP has said while it assumes responsibility for the incident, the company is still waiting for an investigation to show Transocean's role in the matter.
In a statement released late Thursday, BP Group Chief Executive Tony Hayward said the company was increasing cleaning efforts along the shorelines of Louisiana, Mississippi, Alabama and Florida. In addition to 180,000 feet of boom already in the coastal waters, an additional 300,000 feet is staged or in the process of being deployed.
"We are doing absolutely everything in our power to eliminate the source of the leak and contain the environmental impact of the spill," Heyward's statement read. "We are determined to fight this spill on all fronts, in the deep waters of the Gulf, in the shallow waters and, should it be necessary, on the shore."
In a statement released Friday, Halliburton confirmed it performed a variety of services on the rig and had four employees stationed there at the time of the accident.
"Halliburton had completed the cementing of the final production casing string in accordance with the well design approximately 20 hours prior to the incident," the statement read. "The cement slurry design was consistent with that utilized in other similar applications."
Halliburton said tests demonstrating the integrity of the production casing string were completed in accordance with accepted industry practices. At the time of the incident, its statement read, well operations had not yet reached the point requiring the placement of the final cement plug that would enable the planned temporary abandonment of the well, consistent with normal oilfield practice.