It was apparently the EPA, not the Jones Act, that blocked Dutch skimmers from cleaning up the oil spill in Louisiana in late April:
Three days after the BP oil spill in the Gulf of Mexico began on April 20, the Netherlands offered the U.S. government ships equipped to handle a major spill, one much larger than the BP spill that then appeared to be underway. "Our system can handle 400 cubic metres per hour," Weird Koops, the chairman of Spill Response Group Holland, told Radio Netherlands Worldwide, giving each Dutch ship more cleanup capacity than all the ships that the U.S. was then employing in the Gulf to combat the spill. The U.S. government responded with "Thanks but no thanks," remarked Visser, despite BP's desire to bring in the Dutch equipment and despite the no-lose nature of the Dutch offer--the Dutch government offered the use of its equipment at no charge. Even after the U.S. refused, the Dutch kept their vessels on standby, hoping the Americans would come round. By May 5, the U.S. had not come round. To the contrary, the U.S. had also turned down offers of help from 12 other governments, most of them with superior expertise and equipment--unlike the U.S., Europe has robust fleets of Oil Spill Response Vessels that sail circles around their make-shift U.S. counterparts. Ironically, the superior European technology runs afoul of U.S. environmental rules. The voracious Dutch vessels, for example, continuously suck up vast quantities of oily water, extract most of the oil and then spit overboard vast quantities of nearly oil-free water. Nearly oil-free isn't good enough for the U.S. regulators, who have a standard of 15 parts per million--if water isn't at least 99.9985% pure, it may not be returned to the Gulf of Mexico.I earlier cited a news report that attributed this rejection to the Jones Act. That is contradicted by the article found above, which was published later. I regret the likely error.