As the federal government tries to figure out what it will take to restore the Gulf of Mexico to its state before the massive oil spill, BP has become its most significant ally. To some, it simply represents a marriage of convenience, combining local expertise with federal oversight. But with BP well aware that it will be footing the bill for cleanup operations, voices in Congress are arguing that the relationship is too close for comfort. "I want this to be independent, for the credibility of the information," said Sen. Ben Cardin, chair of the Environment and Public Works Subcommittee on Water and Wildlife. Currently, BP has a say in every decision, which experts say is more productive than the approach after the Exxon Valdez spill, when Exxon hired its own experts to follow federal officials and replicate every test to have their own analysis.