After reviewing the model's first five years, the U.S. Government Accountability Office concluded it remains unclear if the approach is an improvement over DOE's previous contracting model.

The audit examined 57 task orders worth nearly $20 billion awarded through March 31, 2025, across nine cleanup contracts at eight U.S. sites formerly used for nuclear weapons production. About half—29 task orders—included defined end states, while the remainder covered transition, support or cleanup work that had not yet established them.

Among 18 selected task orders, GAO found more than $500 million in increased contract values after award, largely because DOE expanded work scopes, extended schedules or otherwise changed requirements during execution.

The largest dollar increases occurred at Oak Ridge Reservation in Tennessee, where an End States Phase-In order increased by $216.7 million, or 45%, and work to construct and commission the Outfall 200 Mercury Treatment Facility increased by $25.8 million, or nearly 139%.

At the Nevada National Security Site, an environmental operations order covering groundwater testing and facility closure cost grew by nearly 150%, largely through planned extensions rather than new task orders.

Looking for quick answers on construction and engineering topics?
Try Ask ENR, our new smart AI search tool. Ask ENR →

GAO also found contract type appeared to influence performance. The firm-fixed-price and cost-plus-incentive-fee task orders it reviewed averaged slightly more than 2% growth, while cost-plus-fixed-fee and cost-plus-award-fee task orders averaged roughly 50%, reflecting the greater financial risk retained by the government under those structures.

Higher contract values did not consistently produce the cleanup outcomes DOE intended. Of six completed task orders with defined end states that GAO reviewed, only two achieved those outcomes as originally planned. One fell short of its cleanup target, while three others had work reduced or transferred to subsequent task orders after award.

At the Hanford site in Washington, GAO found DOE modified the required scope for 12 of 22 completed end states under a $1.8-billion task order performed by Central Plateau Cleanup Co., transferred about $19 million of work into a later task order and lacked sufficient documentation to determine whether three additional end states had been completed.

GAO said the performance problems coincided with weak headquarters oversight. Six selected task orders at Hanford, Oak Ridge and Nevada began before DOE and contractors had finalized scope, cost, schedule and fee negotiations, and four exceeded the generally required 180-day deadline for definitization.

The audit also found "headquarters did not provide adequate oversight" to ensure task orders achieved their defined end states. Contractors played a significant role in developing end states and planning work after master contracts were awarded, making federal oversight more important because task-order work proceeded without further competition.

GAO recommended that the Energy Dept. strengthen headquarters oversight, improve procurement reporting and cost estimating, identify the causes of increased task-order values and ensure undefined task orders are finalized on time. DOE concurred with five of the six recommendations and partially concurred with the one addressing cost growth.

In its response, the Energy Dept. argued that increased task-order values do not necessarily represent uncontrolled overruns because "the complexity of [the] mission can often result in requirement changes" that reduce environmental risk or improve long-term efficiency.

GAO disagreed, saying DOE still needs to identify and address the underlying causes of increased task-order values, including government decisions affecting scope and estimating. Without stronger oversight, the department "cannot assess how well it is meeting program goals," the audit concluded.