In the five months after jet fuel started leaking from Joint Base Andrews into Piscataway Creek, no agency tested the water or sediment some 20 miles downstream, where the creek empties into the Potomac River and the shoreline community and anglers gather to fish and boat along the riverbank.

The leak was detected on Dec. 11 at Joint Base Andrews in Prince George’s County. Of an estimated 32,000 gallons that spilled into the headwaters of the creek, only 10,000 gallons were recovered, while the remaining 22,000 entered the environment. Environmental leaders and activists have criticized the base for waiting more than three months before notifying state regulators.

From the headwaters, the creek runs 18.6 miles before slipping into the Potomac at Fort Washington Park. The public access point there, along the shoreline of the adjacent Piscataway Park, is known for drawing anglers from across the Washington region; the parkland around it is managed by the National Park Service.

The base said it has no plans to do sampling at Fort Washington Park. “We have not conducted water sampling in those specific locations,” said Matt Ebarb, Joint Base Andrew’s media operations chief, in emailed comments. “We have, however, completed multiple joint water-sampling events with the Maryland Department of the Environment at sites on and just off the installation.” The sampling was conducted on April 13, April 20, and May 18 in Piscataway Creek, Ebarb said, adding that the extent of contamination was decreasing over time.