Oil  slick spreads from sunken rig
By  the CNN Wire Staff 
April  22, 2010 6:11 p.m. EDT
                                                                Environmental  impact after rig sinks
  (CNN) -- A 1-by-5-mile sheen of crude oil mix has spread  across the Gulf of Mexico's surface around the area where an oil rig  exploded and sank, a Coast Guard lieutenant said Thursday.
 "This  is a rainbow sheen with a dark center," Coast Guard Rear Adm. Mary  Landry told reporters Thursday afternoon.
 Officials do not know  whether oil or fuel are leaking form the sunken Deepwater Horizon rig  and the well below, but BP Vice President David Rainey said "it  certainly has the potential to be a major spill." BP PLC operates the  license on which the rig was drilling.
 A remotely-operated  vehicle is surveying the area and cleanup efforts are already under way,  Landry said. The sheen "probably is residual from the fire and the  activity that was going on on this rig before it sank below the  surface," she said.
 Meanwhile, the Coast Guard continued to  search for 11 people missing after an explosion late Tuesday set the rig  ablaze forcing workers to be evacuated from the vessel. Officials are  still unsure what caused the blast.
 "We do continue with search  and rescue," Landry said. "As time passes, however, the probability of  success in locating the 11 missing persons decreases."
                                                                                                                                                                                                                                          
Video:  Search for missing oil rig workers                                                                                                                                                                        
Video:  Captain describes rescue efforts                                                                                                                                                                        
Video:  Exec: No indication of problems                                                                                                                                         
Location  of oil rig blast                                                                                                                                               Adrian Rose, a vice president for rig  owner Transocean Ltd, told reporters that the missing workers may not  have been able to get off the rig.
 "Based upon our reports from  crew workers we met as they came in last night, they believe that they  [the missing workers] may have been on board the rig and not able to  evacuate. We have not confirmed that yet," he said.
 The company  is still investigating the incident, but Rose said conversations with  evacuated workers when they arrived onshore revealed "really quite  heroic stories of how people looked after each other."
 The mobile  rig was about 52 miles southeast of Venice, Louisiana, when the  explosion occurred Tuesday night. There were no indications it was a  terrorist incident, the Coast Guard said.
 Officials said 126  people were on board at the time of the explosion. Of the 115  accounted-for workers, 17 injured were evacuated by helicopter from the  rig. Another 94 people were taken to shore with no major injuries, and  four more were transferred to another vessel, according to the Coast  Guard.
 iReport:  Work boat captain captures explosion on film
 It was not known  whether the missing workers were able to make it to one of the rig's  lifeboats -- fully enclosed, fire-resistant vessels designed to evacuate  people quickly.
 The Coast Guardsaid calm weather conditions and  warm Gulf waters increase the likelihood of survival for the missing  workers.
 "We're still searching and there's still a probability  that those crew members are alive," Senior Chief Petty Officer Michael  O'Berry told CNN on Thursday afternoon.
 Carrol Moss told  CNN-affiliate WWL that her husband had been rescued from the rig. But  before she got the call, there were some anxious moments, she said. "The  only thing I was thinking is how am I going to tell my kids that their  dad is not coming home," Moss told the affiliate. "The worst goes  through your mind. We were just blessed we got the call."
 As  rescue crews continued searching for survivors, a federal lawsuit was  filed Wednesday on behalf of one of the 11 missing workers.
 The  lawsuit claims negligence by companies connected to the oil rigs that  caused the explosion. Transocean and BP are named as defendants.
 BP  spokesman Tom Mueller declined to comment on the suit, and a spokesman  for Transocean did not immediately return a call requesting comment.
  The suit does not provide specific details about the blast, but says  one man, Shane Roshto of Amite County, Mississippi, "was thrown  overboard as a result of the drilling explosion, and his body has not  yet been located." His wife, Natalie Roshto, is also named as a  plaintiff.
 Rose, the Transocean vice president, said Thursday  that the company was "deeply saddened" by the incident. "Our thoughts  and prayers remain with the family members and our employees."
 Transocean's  website describes the company as the "world's largest offshore drilling  contractor and the leading provider of drilling management services  worldwide," with 140 offshore drilling units.
 The rig involved in  the explosion -- a mobile unit which moves to different locations in  the Gulf of Mexico -- had been drilling for oil in its current location  since January, said Eileen Angelico, a spokeswoman for Minerals  Management Service, the agency that regulates the oil industry in  federal waters.
 BP spokesman Mueller said dozens of vessels and  aircraft were on the way to the scene Thursday afternoon, including  equipment to minimize the environmental impact of any spilled oil.
 "This  is the kind of thing we drill for every year and plan for it, but hope  we never have to use it. Today is the day we are going to use it. We are  prepared and are moving," he said.
 Up to 336,000 gallons could  spill into the Gulf, based on the amount of oil the rig  pulled out daily, O'Berry told CNN. And up to 700,000 gallons of diesel  fuel could also leak, Coast Guard Petty Officer Ashley Butler said.
 As  cleanup efforts ramped up, government and company officials said they  planned to get to the bottom of what caused the explosion.
 "It's in our national interest, obviously, to know  exactly what went wrong and to make sure something like this never  happens again," Deputy Secretary of the Interior David J. Hayes told  reporters Thursday afternoon.