Japan Ground Self-Defense Force’s CBRN Response


By Col. Takao Yoshizawa

Col. Takao Yoshizawa recalls historical CBRN events in Japan and discusses the structure and work of the country’s main CBRN response organ, the Central NBC Weapon Defense Unit.

The transfer and proliferation of weapons of mass destruction such as CBRN weapons, as well as ballistic missiles that deliver such weapons, have been recognized as significant threats since the end of the Cold War. In addition, in recent years competition and confrontation among states has sharpened and the international security environment has become more complex and fractured. As a result, the international community faces ever-greater difficulties in working together to tackle common challenges such as arms control, disarmament, and non-proliferation.

Within this global security environment, there has been a strong and growing recognition of the danger of CBRN weapons proliferation, which can cause indiscriminate mass casualties and extensive contamination. Transporting these weapons, related equipment, and materials to terrorists and countries under suspicion of proliferating such weapons is also of concern.

The threat of terrorist attacks by weapons of mass destruction in urban areas in Japan was laid bare by incidents such as the series of sarin gas attacks carried out by the Aum Shinrikyo cult in 1994, and 1995 marked the world’s first chemical terrorism incident by a non-state actor.

In Japan, should CBRN weapons be used in a way that corresponds to an armed attack, the Self-Defense Forces (SDF) will conduct defense operations to repel the armed attack and rescue victims. Additionally, should CBRN weapons be used in a way that does not correspond to an armed attack but against which the general police alone cannot maintain public security, the SDF will conduct public security operations to suppress the armed group and rescue victims in cooperation with related agencies.

This article focuses on the activities of the Ground Self-Defense Force’s (GSDF) CBRN response, particularly emphasizing disaster relief operations and introducing a key unit in Japan’s CBRN response, the Central NBC Weapon Defense Unit.

The GSDF’s CBRN Response

The GSDF is the largest defense organization in our country, comprising various units and institutions. It is divided into five regional armies covering Japan, with approximately 160 camps strategically located nationwide for swift responses. Among the CBRN response units are the Central NBC Weapon Defense Unit, the Medical Countermeasure Unit under the Ground Component Command, NBC Weapon Defense Units in divisions and brigades, and medical units within logistic support regiments. Additionally, institutions like the Chemical School contribute to educating about and researching CBRN response.

Strategically positioned in major cities across the country is the largest NBC weapon defense unit with nationwide deployment capabilities, the Central NBC Weapon Defense Unit. This is in addition to smaller NBC weapon defense units in 15 divisions and brigades. These are responsible for conducting CBRN response, surveillance, reconnaissance, and decontamination to support operations.

Locations of GSDFs and NBC Weapon Defense Units, © JGSDF

The Central NBC Weapon Defense Unit

The Central NBC Weapon Defense Unit specializes in CBRN response operations such as surveillance, reconnaissance, and decontamination. It also supports operational units by deploying smoke screens and conducting firefighting. It consists of approximately 200 personnel comprising the headquarters, a headquarters’ company, and two NBC weapon defense units. It is equipped with CBRN response gear such as chemical agent monitoring devices, CBRN reconnaissance vehicles, and decontamination vehicles.

The unit collaborates with the Maritime and Air Self-Defense Forces, as well as with allied and like-minded countries, to conduct CBRN training. The unit also participates in civil protection exercises organized by local authorities to enhance and maintain the necessary CBRN response capabilities. Over the years, the unit has been involved in various operations including security support for national events such as the Tokyo Olympics, Paralympics, and responding to natural disasters.

In March 1995, during the Tokyo subway sarin incident, the unit received a disaster relief order and conducted the decontamination of subway station facilities and subway cars. In March 2011, following the Fukushima Daiichi Nuclear Power Plant accident resulting from the Great East Japan Earthquake, the unit conducted the first-ever dispatch for a nuclear disaster. In this deployment, serving as a core unit of the nationwide chemical units, they carried out tasks such as water cooling of the nuclear fuel pool, monitoring radiation levels in surrounding areas, and decontamination activities. In September 2014, during the disaster relief operation after the eruption of Mt. Ontake, the unit used chemical agent monitoring devices to monitor the flow of volcanic gases, ensuring the safety of search teams.

Unilateral changes or attempts to change to the status quo by force, as well as invasion, are not the only situations that Japan needs to prepare for. Large-scale terrorism and accompanying attacks on critical infrastructure such as nuclear power plants are serious threats to the lives, health, and property of Japanese citizens, and would require Japan to respond with all-out efforts.

To respond to such cases effectively, the SDF would utilize its fundamentally reinforced defense capabilities and closely cooperate with the police, fire departments, local governments, and other related organizations.

Examples of major CBRN equipment, © JGSDF

Preparedness for Disaster Relief Operations

In principle, a disaster relief operation is conducted as follows. Prefectural governors or other officials request the Minister of Defense, or an officer designated by the Minister, to dispatch SDF and other units in the event of a natural disaster. The Minister or the designated officer will make a judgment based on a comprehensive evaluation of three conditions (urgency, non-substitutability, and threat to the public) and dispatch SDF response units if deemed necessary.

Upon receiving notification from prefectural governors or equivalent authorities, the Minister of Defense or a designated individual can dispatch units if there is an urgent need and no time to wait for an official request. In CBRN situations, where identifying the specific substance may take time and the situation develops continuously, the SDF maintains 24-hour standby, known as “Fast Force”, to ensure rapid deployment in case of disasters.

Series of CBRN trainings, © JGSDF

Major Operations in CBRN Situations

The CBRN disaster response policy outlined in the Ministry of Defense Disaster Response Action Plan emphasizes the swift understanding of the situation, prompt unit preparation, deployment, standby, and ensures the health and safety of personnel.

In peacetime, coordination with relevant agencies, planning, and education are prioritized. Through participation in various disaster preparedness exercises, collaboration is strengthened with related agencies to share awareness of potential damages and response procedures. Local governments, police, fire departments, and others collaborate to conduct training based on initial response plans and regularly review them.

In the initial response stage, considerations include assessing the situation, deploying units, transporting specialists, providing monitoring support, supporting the evacuation of residents, offering emergency medical assistance, decontamination, and preventing the spread of damage. Coordination at the local level, such as at incident coordination centers, is crucial due to potential overlaps with ongoing functions of the police, fire departments, and other bodies.

In subsequent stages following the initial response, cooperation with local authorities is maintained to respond appropriately to ongoing decontamination efforts or other requests. If the response prolongs, rotation of deployed units and personnel is considered, considering morale, fatigue, and ensuring the continuation of activities.

Response to disasters, © JGSDF


The response to CBRN situations spans a broad spectrum, ranging from armed attack situations involving CBRN weapons, to terrorism, diseases, natural disasters, and accidents. The Japanese Self-Defense Forces possess and maintain the Central NBC Weapon Defense Unit and the Medical Countermeasure Unit, and are also increasing the number of chemical and medical unit personnel to improve their capabilities in responding to CBRN weapon attacks. The GSDF has also designated initial response personnel who remain ready to mobilize quickly in the event of extraordinary disasters. The Maritime SDF and the Air SDF have also acquired protective equipment and materials to be used on vessels and at bases.

Within the deteriorating global security environment, there has been increased attention paid to collaboration and cooperation among partner countries in addressing CBRN response. Japan, with a record of countering CBRN incidents, is also addressing the challenge of sharing expertise in CBRN response with allied and like-minded countries. Exchanging knowledge and experiences and addressing common challenges in CBRN response will likely be crucial for our collective security in the future.

Col. Takao Yoshizawa is the Commander of the Central Nuclear Biological Chemical Defense Unit of the Japanese Ground Self-Defense Force (JGSDF). He was previously the Director at the Education Department of the JGSDF’s CBRN School. He has a Master’s degree in Aerospace Engineering from the National Defense Academy.

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