A massive oil spill threatens to hit the southern U.S. coast with an environmental disaster, slap energy giant BP PLC with a huge cleanup bill and derail plans to open up more offshore drilling.


The spill — from a rig leased by BP that blew up in the Gulf of Mexico last week — is spewing five times more oil than previously estimated and raising fears of severe damage to fisheries, wildlife refuges and beaches in Louisiana, Mississippi, Alabama and Florida.


“This is a spill of national significance,” Janet Napolitano, the secretary of Homeland Security, told a news conference at the White House on Thursday. “We will continue to push BP to engage in the strongest response possible.”


The accident, which has pounded the share prices of BP and other companies involved in the rig project, may also have major ramifications for proposals in Congress and by President Barack Obama to issue new offshore drilling permits.

Bill Nelson, a Democratic senator from Florida, said he was filing a bill to temporarily prohibit the administration from expanding offshore drilling, citing the risk of a potential “environmental and economic disaster” from the spill.