WASHINGTON — More than 30 gallons of fuel spilled onto the National Mall from generators that were used during a recent event celebrating America’s 250th anniversary that was organized by Freedom 250, a group created by the Trump administration, according to three people familiar with the matter. The fuel from commercial generators at the May 17 event seeped into underground cisterns that collect rainwater to irrigate the Mall, these people said. Four of the cisterns, which hold up to 250,000