Countering Weapons of Mass Destruction Office — 6 U.S.C. §§ 591-597a

6 U.S.C. Subchapter XIV (§§ 590-597a) establishes the Countering Weapons of Mass Destruction (CWMD) Office within the Department of Homeland Security. The CWMD Office is the lead DHS organization for detecting, preventing, and defending against attacks or incidents involving nuclear, radiological, biological, and chemical threats — the four categories of weapons capable of causing mass casualties. Originally created as the Domestic Nuclear Detection Office (DNDO), the office was expanded and renamed by the Countering Weapons of Mass Destruction Act of 2018 to address biological and chemical threats alongside the original nuclear/radiological mission. The CWMD Office coordinates federal detection and response programs, operates the Global Nuclear Detection Architecture (GNDA) — the worldwide network of sensors and systems for detecting illicit movement of nuclear and radiological materials — and administers the Securing the Cities (STC) program, which provides detection equipment and training to high-density urban areas most at risk of a radiological or nuclear terrorist attack. It also houses the Chief Medical Officer responsible for DHS's medical countermeasures programs. For the Department of Energy's parallel nuclear security mission, see the National Nuclear Security Administration (NNSA). For the catastrophic risk management framework that coordinates CWMD and other existential risks, see global catastrophic risk management.

Current Law (2026)

Office Structure and Mission — §§ 590-591h

Establishment — § 591

Section 591 creates the CWMD Office within DHS, led by an Assistant Secretary for the Countering Weapons of Mass Destruction Office, appointed by the President and confirmed by the Senate. The Assistant Secretary reports to the Secretary of Homeland Security.

Mission — § 591g

The CWMD Office must coordinate federal efforts and develop DHS strategy to:

• Detect nuclear, radiological, biological, and chemical threats — both state-sponsored and terrorist
• Prevent the unauthorized importation, possession, storage, transportation, development, or use of WMD
• Defend against such threats through layered detection, deterrence, and consequence management
• Coordinate DHS WMD programs to eliminate gaps and prevent duplication
• Advise the Secretary and inter-agency bodies on WMD threats and policy

Relationship to Other Components — § 591h

Section 591h includes a non-derogation provision: the Assistant Secretary may not override or diminish the authority of any other DHS component (CBP, ICE, FEMA, Coast Guard, Secret Service) or any other federal agency over their own programs and personnel. The CWMD Office coordinates — it does not command other agencies' operational units.

Core Responsibilities — § 592

Section 592 establishes the operational responsibilities of the CWMD Office:

Nuclear and radiological detection:

• Lead and coordinate federal efforts to detect unauthorized nuclear explosive devices, fissile material, and radiological weapons
• Develop and maintain the Global Nuclear Detection Architecture
• Conduct or sponsor research and development of detection technologies
• Deploy detection systems at ports, borders, and other high-risk locations

Architecture development:

• Design, integrate, and continuously improve a layered global detection architecture
• Coordinate detection systems operated by DHS, DOE, DoD, the intelligence community, and foreign partners
• Identify gaps in detection coverage and develop strategies to address them

Interagency coordination:

• Chair interagency bodies on nuclear and radiological detection
• Coordinate with the Department of Energy's National Nuclear Security Administration (NNSA), DoD, and the Director of National Intelligence

Technology Research and Development — § 592a

Section 592a requires a multi-agency technology research and development investment strategy for nuclear and radiological detection. The strategy is developed jointly by DHS (CWMD Office), the Secretary of Energy, the Secretary of Defense, and the Director of National Intelligence.

The strategy must:

• Identify current detection capability gaps
• Prioritize R&D investment to address the highest-consequence gaps
• Coordinate agency R&D efforts to avoid duplication
• Establish milestones and metrics for detection capability improvements

This provision reflects the inter-agency nature of WMD detection: DOE's national laboratories (Los Alamos, Lawrence Livermore, Oak Ridge, Pacific Northwest) are the primary developers of nuclear detection technology; DoD operates detection systems in military theaters; the intelligence community provides threat warning. The CWMD Office integrates these streams.

Testing Authority — § 594

Section 594 gives the CWMD Office (and its contractors) access to federal laboratories, ranges, and test sites operated by other agencies — including DOE national labs and DoD test ranges — for testing detection technologies. This prevents the CWMD Office from needing to build its own full testing infrastructure and leverages existing federal investment in specialized facilities.

Global Nuclear Detection Architecture — § 596a

Section 596a requires the joint annual interagency review of the Global Nuclear Detection Architecture (GNDA). The Secretary of Homeland Security, jointly with the Attorney General, Secretary of State, Secretary of Defense, Secretary of Energy, and the Director of National Intelligence, must conduct this annual review.

The GNDA is the comprehensive, layered system of sensors, intelligence, and procedures for detecting illicit nuclear and radiological material anywhere in the world before it can reach the United States. It includes:

Overseas layers:

• Detection systems at foreign ports with U.S. Megaports Initiative equipment (operated in cooperation with the International Atomic Energy Agency and host countries)
• Container scanning and radiation portal monitors at foreign seaports
• Intelligence collection on nuclear material smuggling networks

At-border layers:

• Radiation portal monitors at all U.S. ports of entry (seaports, land border crossings, airports) — operated by CBP in coordination with CWMD
• Cargo screening systems integrated with ATS (Automated Targeting System)

Interior layers:

• Mobile detection capabilities deployed in high-risk urban areas
• Securing the Cities program assets (see § 596b)
• Law enforcement detection protocols

Securing the Cities — § 596b

Section 596b directs the Secretary to establish the Securing the Cities (STC) program, which provides radiological and nuclear detection equipment, training, and technical assistance to high-density urban areas — cities identified as priority targets for radiological or nuclear terrorism based on population, critical infrastructure, and threat assessments.

STC program components:

• Equipment grants — radiation detection devices (personal radiation detectors, handheld identifiers, vehicle-mounted systems) to police, fire, and emergency management agencies in participating cities
• Training — detection protocols, alarm adjudication procedures, and response exercises
• Exercises — multi-agency drills simulating radiological incidents
• Information sharing — integration of city-level detection data with national threat picture

STC currently operates in a set of designated high-risk urban areas including New York City/New Jersey, Los Angeles, Chicago, Washington D.C., and others. The program is explicitly modeled on the recognition that a radiological dispersal device ("dirty bomb") is among the most credible near-term WMD threats because radiological materials are more widely available than weapons-grade nuclear material.

Chief Medical Officer — § 597

Section 597 creates the position of Chief Medical Officer (CMO) within the CWMD Office, appointed by the President and confirmed by the Senate. The CMO:

• Advises the Assistant Secretary on medical and public health aspects of WMD threats
• Coordinates DHS's medical preparedness programs
• Oversees the Medical Countermeasures Program (§ 597a)
• Coordinates with the Department of Health and Human Services (HHS), including BARDA (Biomedical Advanced Research and Development Authority) and CDC

Medical Countermeasures — § 597a

Section 597a authorizes a Medical Countermeasures Program within the CWMD Office. The program protects DHS personnel — including CBP officers, TSA officers, Coast Guard, Secret Service, and other DHS employees — who are at elevated risk of WMD exposure due to their front-line roles at borders, ports, and security assignments.

The program coordinates with HHS on:

• Stockpiling and pre-positioning of antidotes, antitoxins, and post-exposure prophylactics
• Medical response protocols for DHS personnel following a WMD incident
• Training for DHS medical personnel and first receivers

How It Affects You

If you work at a U.S. port of entry (CBP officer, port worker, maritime professional): Radiation portal monitors at your port of entry are operated under the CWMD/CBP coordination framework. If a container or vehicle triggers an alarm, CBP officers follow protocols developed with the CWMD Office for alarm adjudication — determining whether the radiation signature is dangerous (special nuclear material) or benign (medical isotopes in shipped cargo, naturally occurring radioactive materials in certain ores). False alarms from legitimate shipments (medical equipment, fertilizers, ceramics) are a routine challenge at ports.

If you are in emergency management or public safety in a major city: The Securing the Cities program is a direct source of detection equipment and training for your jurisdiction. Participation requires coordination with DHS and integration of city detection capabilities into the national GNDA picture. Designated STC cities receive equipment and training at no cost; non-STC cities may still access equipment through FEMA Homeland Security Grant Program funds.

If you work in nuclear energy, medicine, or research: Shipments of radioactive materials (reactor fuel, medical radioisotopes, research sources) are routinely flagged by CBP radiation portal monitors. The CWMD Office maintains protocols for rapidly clearing legitimate shipments after alarm adjudication — time matters for short-half-life medical isotopes. Contact CBP or CWMD through your compliance attorney if you repeatedly experience delays.

If you are in the defense or detection technology industry: The CWMD Office is a significant R&D and procurement customer for radiation detection technology, biological threat detection systems, and chemical agent sensors. The § 592a investment strategy shapes federal R&D priorities and procurement programs.

State Variations

The CWMD Office is a federal program; there is no state-level analog. However:

• States and localities are the end-users of most CWMD detection equipment through STC grants and other programs
• State emergency management agencies coordinate with CWMD on WMD response planning under FEMA's Emergency Support Function #10 (hazardous materials/CBRN)
• Some states maintain their own WMD civil support teams — National Guard units trained and equipped for WMD incidents — which coordinate with the federal CWMD/GNDA architecture

Recent Developments

The CWMD Office's scope expanded significantly after the 2018 legislation that added biological and chemical threats to the original nuclear/radiological mission:

• COVID-19 provided an involuntary stress test of DHS's biological threat detection and response capabilities; the CWMD Office's biological mission area has received increased attention and resources since 2020
• Nuclear smuggling threats — the threat of radiological and nuclear material theft from post-Soviet states, and the potential for non-state actors to acquire radiological materials, continues to drive GNDA investment
• Ukraine conflict — Russian nuclear threats and the security of Ukrainian nuclear facilities increased congressional and executive focus on GNDA coverage in Europe and domestic preparedness
• Fentanyl/chemical nexus — while fentanyl is not a WMD, its detection at ports of entry has created coordination points between CWMD detection infrastructure and CBP's drug interdiction mission; some detection technologies serve dual purposes
• Technology modernization — next-generation radiation detection (advanced spectroscopic portal monitors, standoff detection, AI-assisted alarm adjudication) is an active area of CWMD R&D investment