Despite recent mediation efforts, state officials say the U.S. Department of Energy is still delaying an agreement that would update the plans and timelines to clean up the hexavalent chromium plume that has lingered beneath Los Alamos National Laboratory for decades.
No cleanup work has been underway since November 2025.
The plume, a byproduct of LANL activities between 1956 and 1972 that led to chromium-contaminated water seeping beneath Sandia and Mortandad canyons, is a mile long and over 2,000 feet wide — and it has moved.
State and federal officials drafted updated settlement documents for the federal agency after a meeting in August, but as of Thursday they had not been signed.
“The fact that it’s been nine weeks on the chromium cleanup settlement … it’s hard for me to say that they’re acting in good faith any longer,” state Environment Secretary James Kenney said.
Repeated delays
The plume was first detected in 2004. A 2016 consent order began the official process of dictating its cleanup, spearheaded by the Department of Energy’s Environmental Management office in Los Alamos and legacy waste cleanup contractor N3B.
But that process has faltered several times as state officials’ concerns grew over the method of cleanup and its potential impacts.
The Energy Department’s primary method of remediation was to pump, treat and reinject the treated water into the plume. In 2023, that work was paused after state officials found elevated levels of the contaminant in nearby monitoring wells.
The work resumed in 2024 with modifications, according to the Department of Energy. About one year later, in November 2025, those measures were halted again after state regulators realized the plume had spread below San Ildefonso Pueblo. Prevented from reinjecting treated water into the plume, the DOE also stopped pumping and treating, too.
“What we told the Department of Energy to do is you can’t inject anymore because you’re pushing the plume around,” Kenney told The New Mexican. “We didn’t say you can’t pump it up or treat it” to discharge into the Rio Grande, Kenney said.
By February 2026, the Environment Department had issued a compliance order for DOE’s failure to meet cleanup obligations. In August, state and federal representatives met in Washington, D.C., to discuss the compliance order and develop a plan for continued cleanup.
The meeting was “productive” and established a framework for remediation, according to a recent letter from Kenney to San Ildefonso Pueblo officials.
But federal officials still haven’t signed the settlement documents that resulted from that meeting, and Kenney indicated he might take more drastic steps if they don’t.
“If DOE declines to formalize our agreement, NMED must protect the public and the Pueblo through active enforcement litigation,” he wrote.
Kenney noted that while many Energy Department employees on the ground are eager to resolve the issue, a legally binding framework is necessary.
“We work off milestones and deadlines, and that’s what the settlement agreement puts in place,” he said. “They just need to execute it, “ he said. Once that happens, real cleanup work can begin “as opposed to again this aspirational way of treating the chromium plume.”
‘No immediate threat’
During Thursday’s meeting of the state Legislature’s Radioactive and Hazardous Materials Committee, federal representatives offered “takeaways” regarding their cleanup efforts.
Stanley Pyram, acting manager of the Environmental Management Los Alamos Field Office, said they’re paying $400,000 to maintain a treatment system that has ceased operations since the 2025 order to stop all injections.
Pyram also said the plume poses “no immediate threat” to public or private drinking water. “However, it is still moving slowly. Doing nothing is not a solution to the challenge we have,” he said.
Kenney saw it differently.
“It’s uncontained,” he said. “It’s been uncontained for 50-plus years, so the fact that it’s not in people’s drinking water is both surprising already, but the fact that it’s still migrating is entirely a threat.”
Lawmakers weigh action
Sen. Jeff Steinborn, D-Las Cruces, the committee chair, asked Pyram and N3B President Brad Smith why there has been a delay in finalizing the settlement agreement.
“We’re working on some of the terms of that settlement,” Pyram said. “There were some parts of it where there was some disagreement to a certain extent.”
Pyram said he is moving forward with technical work where possible to be prepared when the settlement is finalized. Steinborn said the state needs to see more.
“I think not having an agreement means we do not have a commitment,” Steinborn said. “One thing I’m exploring is the possibility of the … Legislature actually getting involved in statutorily, legally dictating the chromium cleanup case, which I would rather the parties resolve.”
The state began the process of revising the federal government’s plan for disposing of legacy waste at the Waste Isolation Pilot Plant in Carslbad earlier this year, citing a “retreat” of obligations. While state officials expected the permitting revisions to be finalized this fall, no final agreement has been announced.
The Department of Energy also recently came under scrutiny by state legislators for handicapping the U.S. Defense Nuclear Facilities Safety Board, which monitors safety conditions and procedures.
Lawmakers on the Radioactive and Hazardous Materials Committee signed a letter in September calling on federal officials to “bring the [Department of Energy] back into compliance with federal law” and to restore access to the oversight agency.
The Department of Energy did not respond to questions by deadline Thursday.
Victoria Traxler is an environment and national labs reporter for The New Mexican.
