A Department of Homeland Security watchdog found that U.S. Customs and Border Protection may have violated the Antideficiency Act while building a prototype radiation-detection system, spending more than $5 million in appropriations authorized for other purposes over a six-year span without required departmental sign-off.
Background
CBP relies on mobile radiation portal monitors, known as mRPMs, to screen cargo and vehicles for nuclear and radiological threats at the 22 highest-volume seaports in the United States, a mission required under the Security and Accountability for Every Port Act. To keep that detection capability current, CBP set out to develop a "Next Generation" mRPM prototype through research and development work.
The DHS Office of Inspector General reviewed how CBP funded and managed that effort in report OIG-26-15, released July 22, 2026. Rather than opening the acquisition through DHS's normal research channels, CBP used an existing interagency agreement with a Federally Funded Research and Development Center operated by the Department of Energy to build the prototype. OIG found that approach let CBP sidestep coordination that was supposed to run through both DHS's Science and Technology Directorate and the department's Countering Weapons of Mass Destruction Office, which holds acquisition authority over radiological and nuclear detection programs.
Key Details
OIG's central finding is a violation of the purpose statute, 31 U.S.C. § 1301(a), which requires federal agencies to spend appropriated funds only on the purposes for which Congress authorized them. The inspector general determined that CBP spent more than $5 million in appropriations designated for other purposes to procure the Next Generation mRPM prototype across fiscal years 2019 through 2024. OIG classifies that spending as questioned costs and states that, as a result, "CBP may have violated the Antideficiency Act," the law that bars federal agencies from obligating or spending funds in excess of, or outside the scope of, what Congress has appropriated.
The report also documents a breakdown in internal awareness. According to OIG, the CWMD Component Acquisition Executive — the official responsible for overseeing acquisition of radiological and nuclear detection technology across DHS — did not know the prototype program existed until a field demonstration in May 2023, years after CBP began funding the work. That gap meant the office charged with acquisition oversight for this category of technology had no opportunity to review the program's funding structure or scope before it was well underway, and it meant CBP had already spent years and millions of dollars building the prototype before anyone with statutory acquisition authority over radiological and nuclear detection technology was even aware the effort existed.
OIG's review makes clear that the problem was not the choice to build a next-generation radiation-detection prototype itself, but how CBP chose to fund and route it. Using an interagency agreement with a Department of Energy-run FFRDC gave CBP a fast, flexible mechanism for getting technical work started. But that same mechanism let the program bypass the review gates DHS built specifically to catch funding and scope problems in radiological and nuclear detection research before they compound over multiple fiscal years, which is exactly what happened here.
OIG issued two recommendations in the report. The first directs CBP to identify and correct any Antideficiency Act violations tied to the prototype procurement. The second calls for improved research-and-development oversight specifically for radiological and nuclear detection programs, to prevent similar funding and coordination lapses going forward. CBP concurred with the second recommendation, and OIG has closed it as resolved. CBP did not concur with the first recommendation — the one requiring the agency to identify and correct potential Antideficiency Act violations — and OIG has left that recommendation open and unresolved, meaning the underlying funding question remains unsettled between the agency and its watchdog.
The Antideficiency Act carries real consequences beyond a paperwork citation. Confirmed violations typically trigger a formal reporting chain that runs from the agency to the Office of Management and Budget, the President, and Congress, and can expose responsible officials to administrative discipline. OIG's finding stops short of a confirmed violation — it uses "may have violated" language and frames the $5 million as questioned costs pending CBP's own review — but the report puts the question squarely in CBP's hands to resolve, and CBP has so far declined to do so.
What It Means for Contractors
Contractors working with CBP and DHS on research-and-development efforts, particularly through FFRDC or other-transaction and interagency-agreement vehicles, should read this report as a reminder that the funding source behind an R&D task order matters as much as the technical scope. An interagency agreement can move a program forward quickly, but OIG's findings show that speed came at the cost of routing the funding and the underlying technical scope through the offices with statutory authority to approve it. Contractors and FFRDC partners executing work under similar arrangements should confirm that the government customer's task orders and funding citations have been validated against the specific appropriation's authorized purpose, not just against the program's general research mission.
The report is also a signal that DHS's own acquisition oversight structure — specifically the CWMD Component Acquisition Executive's authority over radiological and nuclear detection technology — is being actively tested by OIG audits, and that gaps in that structure can surface only after a program has been running for years. Firms bidding on or performing radiological and nuclear detection work for CBP, the Transportation Security Administration, or other DHS components should expect closer scrutiny of how new prototype and pilot efforts get funded and approved going forward, given OIG's open recommendation on R&D oversight improvements.
Finally, because CBP has not concurred with the recommendation to identify and correct the potential Antideficiency Act violations, contractors involved in the Next Generation mRPM program specifically should anticipate continued OIG attention to this file. An open, unresolved recommendation on a questioned-costs finding of this size means the report is unlikely to be the last word from either OIG or CBP on how the prototype was funded, and any follow-on procurement tied to the program could face additional review before it proceeds.
