Greenpeace said it disagreed with official statements that most of the oil from the BP spill is gone from the Gulf of Mexico and added that it has a laboratory test to confirm crude from the catastrophe still sits on the seafloor.

"We're still seeing a lot of oil out there," John Hocevar, a marine biologist with Greenpeace, said during a news conference to mark the end of a three-month expedition by the group's Arctic Sunrise vessel. "It's on the surface, it's in the sediment, it's in the water column and it's hundreds of miles away from the spill site."

Federal agencies have said that most of the oil spilled into the Gulf has evaporated, dissipated, been dispersed or been burned and skimmed. As early as Aug. 4, U.S. officials said only 52.7 million gallons of oil were left in the Gulf, about 31 percent of the 172 million gallons that spewed into the water from the broken BP well. Government scientists also say they have not found any visible oil on the sea floor so far.

"They have often made it appear that everything is fine when it wasn't," Hocevar said.

He said the White House should have waited before lifting the moratorium on drilling in the Gulf because "there's an awful lot that we need to understand (about the spill) still."

Officials with the Coast Guard and the National Oceanic and Atmospheric Administration did not immediately return telephone calls seeking comment.

Hocevar said Greenpeace recently received test results from a single oiled sediment sample taken in late September from 1 mile deep and about 4½ miles from the spill site. He said the tests confirmed that the oil in the sediment was from the BP spill.

Hocevar said Greenpeace wanted to take one sample and prove that the oil was from the BP spill. University scientists have said they have found oil on the sea floor, but it has taken far longer for them to get results for their large batches of samples, he said.

Samantha Joye, a marine scientist with the University of Georgia, said by e-mail that she has been waiting for five weeks to get lab results "fingerprinting" oil she found on the sea floor in early September. Only a few labs are able to do the detailed analysis to determine if oil found in the Gulf is the same oil that came out of BP's busted well.

The Arctic Sunrise spent three months looking for oil and marine life in trouble after it arrived in the Gulf following the April 20 explosion of the Deepwater Horizon drilling rig. Over that period, the Greenpeace vessel also helped about 20 scientists conduct a variety of oil spill research, Hocevar said.

One of those scientists, Caz Taylor, a population biologist and blue crab researcher at Tulane University, said that she was concerned about blue crab populations. On journeys aboard the Arctic Sunrise, she pulled in blue crab larvae across the Gulf - from Galveston, Texas, to the Florida Panhandle - and found "mysterious orange droplets" on them, she said at the news conference.

Extensive lab testing would help determine if the orange blobs on the larvae were caused by the oil spill, she said.

The Arctic Sunrise departs New Orleans on Wednesday for Mexico. Greenpeace officials did not say whether the ship would be back in the Gulf any time soon. The environmental group uses the vessel around the world. The 164-foot long ship is capable of breaking ice and includes a helipad.