The two types of dispersants British Petroleum is using to clean up the Gulf oil spill are approved by the U.S. Environmental Protection Agency but banned in the United Kingdom, ProPublica reports.

EPA data suggest these products, from the Corexit line of dispersants, are more toxic and less effective in handling southern Louisiana crude than those made by competitors, Greenwire reports. Dispersants work by breaking oil into droplets.

ProPublica learned of the U.K. ban from Rep. Edward J. Markey, D-Mass., who told the New York Times that the ban occurred because of "harmful effects" on sea life.

"The release of hundreds of thousands of gallons of chemicals into the Gulf of Mexico could be an unprecedented, large and aggressive experiment on our oceans," Markey, chairman of the House Subcommittee on Energy and the Environment, told the Times. "The information regarding the chemical composition, efficacy and toxicity of the dispersants currently being used is scarce." Read Markey's letter to the EPA, here.

ProPublica reported earlier that a compound in Corexit has been linked to headaches, vomiting and reproductive problems at high doses.

BP spokesman Jon Pack said Corexit was "pretty effective" and "rigorously tested," according to Greenwire.

EPA Administrator Lisa Jackson told a Senate panel that EPA is working with BP to get less toxic dispersants to the site as quickly as possible, reports Kate Sheppard of Mother Jones.

(Posted by Jessica Durando)