An employee with the governor&#39;s office collects oil for research purposes in Bay Jimmy on June 15, 2010 off of Grand Isle, Louisiana. The BP spill has been called the largest environmental disaster in American history. U.S. government scientists have estimated that the flow rate of oil gushing out of a ruptured Gulf of Mexico oil well may be as high 40,000 barrels per day. Following his fourth trip to the Gulf on Monday, President Barack Obama will address the nation in an Oval Office speech today on the situation in the Gulf.