Environmental Management Los Alamos Field Office

EM-LA’s top environmental remediation project is the hexavalent chromium plume in Mortandad and Sandia Canyons at Los Alamos National Laboratory (LANL). The primary source of the plume was a non-nuclear power plant at LANL that periodically flushed coolant water containing potassium dichromate from the plant’s cooling towers into Sandia Canyon from 1956-1972. Potassium dichromate (the primary contaminant of concern is hexavalent chromium) was a permitted effluent used as a descaling agent in power plants worldwide during this time. Up to 160,000 lbs. of hexavalent chromium was released from the cooling towers, a small portion of which migrated into the regional aquifer.

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In March 2024, EM-LA and NMED convened a team of experts from the Network of National Laboratories for Environmental Management and Stewardship, industry, academia, and EPA Region 6 to perform a technical review and help facilitate a technical discussion and resolution of EM-LA and NMED’s differing professional opinions. 

Prior to finalization of the report, EM-LA worked together with NMED to resume partial operation of the Chromium IM on September 30, 2024. The IM is running 24/7 as expected with two extraction wells and three injection wells.

The Hexavalent Chromium Project Expert Technical Review Team has issued the Independent Review of the Chromium Interim Measures Remediation System in Mortandad Canyon Los Alamos, New Mexico, December 2024 report.

Final Chromium Project ITR Report (w/ Appendices)
Chromium Report Expert Technical Review Charge Letter
Chromium Project Expert Technical Review Team Members

The Environmental Management Los Alamos Field Office’s (EM-LA) Solid Waste Stabilization and Disposition Project Team is dedicated to packaging, shipping and disposing legacy waste – low-level, mixed low-level, and transuranic (TRU) waste – from Los Alamos National Laboratory (LANL). The most challenging legacy waste at LANL is TRU, which is currently stored at Area G, located on a mesa 1.3 miles north of the residential community of White Rock and about 600 feet west of the Pueblo de San Ildefonso boundary with LANL. Opened in the late 1950s, Area G is the primary facility at LANL that characterizes and remediates TRU waste.

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Technical Area 16 (TA-16), located in the southwestern corner of Los Alamos National Laboratory, was established to develop explosive formulations, cast and machine explosive charges, and assemble and test explosive components for the nuclear weapons program. Water was used in the process of casting and machining high explosives, including Royal Demolition Explosives (RDX). Process water containing RDX flowed into settling “ponds” and ultimately into Cañon de Valle between 1951 and 1996, resulting in contamination of nearby springs, surface water, and groundwater. Corrective Measures Implementation to address surface and shallow subsurface RDX contamination was completed in 2017. DOE's current focus is to complete the characterization of contamination in the perched and deeper groundwater and prepare a comprehensive investigation report.

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Technical Area 21 (TA-21) is among the earliest of the Technical Areas to be constructed at Los Alamos National Laboratory. It was originally called the Delta Prime (DP) Site and may have pre-dated the use of “Technical Areas” to describe sites. It was divided into two sections, with DP West being a former radioactive material processing area, and DP East containing tritium facilities that provided space for energy, environment and weapons defense research.

TA-21 is also the site of the laboratory’s oldest waste disposal area, Material Disposal Area (MDA) B. This MDA and the other MDAs at TA-21 received waste for disposal intermittently from 1945-1977.

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