WASHINGTON (AFP)--More than 20 countries, from Canada to Japan, have offered assistance to the U.S. over the Gulf of Mexico oil disaster, very little of which has been accepted, the State Department said Thursday. Initially it turned down offers, but with workers locked in a race against time to stem the massive spill, the State Department is now playing an active role in the response effort and has appealed for certain boom and skimmers. Most offers are still "under consideration," some dating back to just weeks after the BP-run Deepwater Horizon rig sank on April 22, triggering the worst environmental disaster in American history. Only one offer, some dispersant from France, has been declined outright and that was only because the chemicals it was offering aren't approved for use in the U.S., the State Department said. Almost 10,000 feet (3 kilometers) of boom from Canada, 13,780 feet of boom from Mexico, skimmers and three sets of sweeping arm systems from the Netherlands, and eight skimmers and more boom from Norway, have been accepted. The U.S. has said it will pay for whatever foreign assistance it receives, although BP PLC (BP) has purchased much of the equipment accepted so far. The 22 countries offering assistance are: Belgium, the U.K., Canada, China, Croatia, France, Germany, Ireland, Japan, Kenya, Mexico, the Netherlands, Qatar, Norway, Romania, Russia, South Korea, Spain, Sweden, Tunisia, the United Arab Emirates and Vietnam. Many offered their help through the International Maritime Organization, which is also sending notifications about the spill to its 169 member states. Croatia's mysterious offer of a "proposed solution" has been shown to engineers and technical experts and will be incorporated into the response as needed, the State Department said, without providing further details. (END) Dow Jones Newswires June 17, 2010 21:32 ET (01:32 GMT)