Wednesday’s Kentucky Derby Festival Great Steamboat race may be the last for the Delta Queen riverboat.For the last 45 years the Delta Queen has raced the Belle of Louisville as part of the festival. For 42 of those years, it’s been illegal to operate boats with wooden structures like the Queen’s, because of a Coast Guard fire safety rule.The paddlewheeler has typically received an exemption from Congress, but that’s about to expire and an effort to extend it has been held up in a congressional committee.Mark Shallcross with the Kentucky Derby Festival says representatives from Kentucky, Indiana and Ohio tried to expedite the exemption to no avail.“There was an attempt to attach it to a Coast Guard bill in Congress earlier this week and that did not succeed," says Shallcross. "Unless they get another exemption to keep making overnight cruises, the Delta Queen will no longer be able to participate in the Great Steamboat Race”Shallcross says if the Delta Queen is grounded next year, the festival will find another competitor for the Belle.