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.

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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 gallons, are under the National Mall. The people familiar with the matter said efforts to clean up the spill are underway.

Representatives from Freedom 250 said the incident was the result of “vandalism.”

“Following the Freedom 250 team’s installation of temporary lighting on the National Mall, our equipment has been repeatedly targeted by vandals. The recent fuel leak was the direct result of that tampering,” Rachel Reisner, spokeswoman for Freedom 250, said in a statement provided to NBC News.

“Upon discovering damage to a generator fuel line, Freedom 250 and our vendors mobilized within minutes, coordinated an immediate cleanup response, and fully remediated the site in close partnership with the National Park Service,” Reisner said. “We take our responsibility as stewards of the National Mall seriously and are working closely with the appropriate law enforcement authorities regarding these acts of vandalism.”

The administration established Freedom 250 as a public-private partnership to fund and plan events celebrating the 250th anniversary of the adoption of the Declaration of Independence. It is separate from the nonprofit America250, which Congress established 10 years ago and is led by a bipartisan group of lawmakers and private citizens.

On Monday morning, NBC News observed a “Mobile Command Center” owned by Lewis Environmental, an environmental remediation company, on the Mall at the site where the Freedom 250 event took place, as well as more than a dozen “Rain for Rent” trailers.

The event on May 17, titled “Rededicate 250,” drew thousands of people to the Mall for a day of prayer, music and speeches from religious and political leaders, including Secretary of State Marco Rubio, Defense Secretary Pete Hegseth and House Speaker Mike Johnson, R-La.

One of the people familiar with the matter said the National Park Service would typically hold the permit holder liable for the environmental mitigation after a spill of such magnitude, but it is unclear whether Freedom 250 and Event Strategies Inc., which helped organize the events, are on the hook for the cleanup costs.

National Park Service guidelines indicate commercial liability insurance would be required as part of the permit for an event of such size and scope.

Another of the people familiar with the matter said the spill adds to doubt about the future of the grass on the National Mall, which was already vulnerable given the number of high-foot-traffic events planned there over the coming weeks. They include celebrations of the nation’s 250th anniversary, such as a Great American State Fair and a Fourth of July Salute to America, as well as an IndyCar race planned for August.

The National Park Service and Lewis Environmental have not responded to requests for comment. Washington police referred a request for comment to the National Park Service.