"Based on current information, USEPA has determined that free oil product, which includes ignitable substances, remains in the groundwater and presents a threat of discharge to navigable waters and to human health and the environment," the EPA said in an amended order to BP issued Wednesday.

"Continued pumping of such free product is the most effective way to abate the threat."

BP has sucked up more than 377,000 gallons of oily liquids from groundwater and recovered 18,500 gallons of oil near the spill site by 175th and White Oak Avenue.

EPA initially ordered BP to remove all contaminated soils by Wednesday.

EPA has not given BP a new deadline, but merely said BP has to "remediate the oil and contaminated soil without delay" and must continue to extract oil "to avoid risks posed by ignitable substances."

BP also has to remediate any potentially affected areas along the Little Calumet River and the Grand Calumet River.