Diesel fuel has spilled onto the National Mall at least twice in the past two weeks during preparations for an event celebrating the country’s 250th birthday, according to a government document and a spokeswoman for the Interior Department.
The first spill occurred on May 20 and contaminated a cistern that provides water for irrigating the grass on the Mall in the heart of Washington, according to the document and the spokeswoman. The second incident happened Wednesday night, and its environmental impact remains unclear.
The total amount of diesel released on the Mall is not certain. The federal government said the first spill involved 30 gallons of fuel, while the nonprofit organizing the event said it was between 2 gallons and 2.5 gallons. Neither party said how much fuel leaked in the second incident.
In both cases, the fuel came from supply lines connected to diesel-powered lighting systems installed for the Great American State Fair, a 16-day event that is set to kick off on June 25 and transform the Mall into a sprawling festival ground.
Event Strategies Inc., a Virginia-based firm with close ties to the Trump administration, was overseeing the installation of the lighting systems. The same firm helped organize a rally at the White House Ellipse on Jan. 6, 2021, where President Trump addressed a crowd about the 2020 election before some of his supporters stormed the Capitol.
Event Strategies was hired by Freedom 250, a nonprofit established by the administration to oversee a number of events celebrating America’s 250th birthday. In addition to the fair, Freedom 250 is planning an IndyCar race around the Mall and an Ultimate Fighting Championship match on the White House lawn.
The cause of the spills is contested.
According to Katie Martin, a spokeswoman for the Interior Department, both incidents resulted from vandalism. She said the fuel lines were intentionally slashed, possibly by a critic of Mr. Trump’s efforts to remodel parts of Washington ahead of the semiquincentennial.
“Just last night an individual cut a fuel line to a light tower in an attempt to stop the great work being done to celebrate our nation’s 250th,” Ms. Martin said in an email on Thursday. “This is unhinged behavior that will not be tolerated. To be crystal clear: We will not be stopped. This administration continues to revitalize the city at record speed.”
Rachel Reisner, a spokeswoman for Freedom 250, said the spills were a “direct result” of tampering.
“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,” Ms. Reisner said in a statement.
A U.S. Park Police report on the second incident said that a “preliminary investigation revealed that an unknown individual intentionally cut the diesel fuel line to a light pole, resulting in a fuel spill.” The report did not indicate how much fuel spilled Wednesday night.
The U.S. Park Police did not respond to a request for any existing report for the May 20 spill.
A government document about the first spill that was reviewed by The Times said a supply line had “failed” and that “the spill originated from event-related equipment that lacked required secondary and tertiary containment measures.” It made no mention of vandalism.
The document said approximately 30 gallons of diesel fuel had spilled in that incident, contaminating gravel surfaces, storm drains and the cistern that supplies water for irrigating grass on the Mall. (The cistern does not provide Washington’s drinking water, which comes from the Potomac River.)
It indicated that the National Park Service was seeking a contractor to remediate the May 20 spill at a cost of about $1.1 million, although Ms. Martin said the cleanup could end up costing far less.
It was unclear how vandals would have reached the fuel lines, which were located inside a fenced area on the Mall and were not visible from the streets.
On Thursday afternoon, a security guard sat in a folding chair behind a break in the fences, near a sign that said “This site is under 24-hour surveillance.” The guard declined to speak to a reporter.
When spilled, diesel can seep into soil and cling to asphalt and concrete. A toxic petroleum product, diesel evaporates more slowly than gasoline, meaning it can remain in the environment for extended periods.
Both Event Strategies and the Interior Department said the company would reimburse the government for cleanup costs.
The spills do not appear to have been disclosed to the public or to District of Columbia authorities. Ed Stierli, the senior director for the Mid-Atlantic region at the National Parks Conservation Association, an advocacy group, said he was disappointed to learn of the incidents.
“We hope that the organizers and the National Park Service ensure that all of the Freedom 250 activities leave the National Mall exactly as they found it,” Mr. Stierli said. “This is an irreplaceable public space.”
The Great American State Fair will feature a 110-foot Ferris wheel, military demonstrations and pavilions serving food from all 50 states and six U.S. territories. Performers will include the country music star Martina McBride and the rappers Flo Rida and Vanilla Ice, Freedom 250 announced on Wednesday.
Event Strategies, based in Northern Virginia, is staffed by veterans of Mr. Trump’s campaigns and first administration. It has received government contracts worth $22 million in Mr. Trump’s second term. The firm has planned celebrations of the Navy’s 250th birthday and a Treasury Department event to tout new investment accounts for children called “Trump accounts.”
The Mall has recently seen a spike in vandalism, Ms. Martin said. She also provided a copy of a police report from May 17 in which officers reported graffiti that said “86 47” in two locations, including on temporary fencing near a subway entrance.
“86 47” is a phrase sometimes used by Mr. Trump’s critics at protests. The Justice Department last month indicted James B. Comey, the former F.B.I. director, over a photo he posted on social media last year of seashells on a beach that formed the numbers, calling it a threat against the president.
