Rep. Edward Markey, D-Mass., said he will send a letter to BP and ask federal agencies for more details about how they analyze the oil leak, CNN reported Friday.
"I am concerned that an underestimation of the oil spill's flow may be impeding the ability to solve the leak and handle the management of the disaster," Markey said in a statement Thursday. "If you don't understand the scope of the problem, the capacity to find the answer is severely compromised."
BP officials have said 5,000 barrels -- or 210,000 gallons -- of crude have been leaking into the gulf every day since the Deepwater Horizon oil rig exploded April 20, killing 11 workers. However, a researcher at Purdue University said about 70,000 barrels of oil per day may be gushing into the gulf after analyzing videos of the spill.
Associate Professor Steve Wereley said there is a 20 percent margin of error, which means between 56,000 and 84,000 barrels could be leaking daily, CNN reported.
"You can't say with precision, but you can see there's definitely more coming out of that pipe than people thought. It's definitely not 5,000 barrels a day," Wereley said.
Ian R. MacDonald, an oceanographer at Florida State University and an expert in analyzing oil slicks, told The New York Times his calculations suggested the leak could "easily be four or five times" the publicized estimate.
BP spokesman Mark Proegler said the company stands behind its 5,000-barrel estimate. he said the company used data, satellite imagery and consultations with the U.S. Coast Guard and the National Oceanic and Atmospheric Administration to draw its conclusion.
"We are focused on stopping the leak and not measuring it," he said.
Meanwhile, work to deploy a second containment box designed to staunch the oil flow continues, BP officials said on the company's Web site.
Because a system like that hasn't been used at a water depth of 5,000 feet, its success was uncertain, officials said. Crews are expected to begin deployment within the next few days.