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It’s Time to Combine

Integrating the U.S. Army Chemical Corps into the Engineer Regiment

Lt. Col. Eric G. Flood, U.S. Army

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Test participants from the Reconnaissance Platoon, Headquarters and Headquarters Company, 23rd Brigade Engineer Battalion, launch a small unmanned aircraft to conduct remote detection of biological warfare agents while conducting standoff scanning with the Sensor Suite Upgrade on an M1135 nuclear, biological, chemical reconnaissance vehicle 20 October 2023 at Yakima Training Center, Washington. (Photo by Tad Browning, U.S. Army)

It is in the Army’s best interests economically and organizationally to integrate the Chemical Corps into the much larger Engineer Regiment by tasking the engineers to take responsibility for CBRN (chemical, biological, radiological, and nuclear) soldiers and capabilities as a uniquely capable subset within the already diverse engineer formations. This reorganization would reflect future Army priorities, reduce unnecessary higher headquarters, retain key capabilities, offer more opportunities for soldiers, better align with key allied nations, and leverage the historic relationships between the engineers and the Army’s CBRN soldiers.

The Engineers: Already Diverse by Nature

The Engineer Regiment is one of the most diverse organizations in the U.S. Army. Its capabilities span from frontline sappers clearing obstacles for and fighting as infantry to facilities engineering in garrison ensuring that maintenance contracts are executed properly and in accordance with the statement of work. Army engineers build roads, airfields, and buildings in support of worldwide military efforts and provide technical geospatial expertise to commanders at multiple echelons.

The U.S. Army Corps of Engineers (USACE) districts maintain much of the Nation’s civil infrastructure. From dredging ports to maintaining hydroelectric dams, they are commanded by active-duty engineer officers.

Engineers serve as enabler integrators for maneuver commanders and are used to picking up unique units that lack a local higher headquarters and making them part of their team. It is due to this enabler integration culture that, within the brigade combat team (BCT) structure, it is the brigade engineer battalion that holds the brigade’s military intelligence company, signal company, and chemical platoon.¹

The Chemical Corps: Relevance in Modern Warfare

The Chemical Corps provides the Army with several niche capabilities, particularly in the realm of CBRN reconnaissance and decontamination. However, the consistent challenge for the Chemical Corps has been relevancy. Since the United States does not have nor plans to use chemical weapons, the U.S. Army Chemical Corps has no ability to provide maneuver commanders with an offensive capability.² The Corps is entirely reliant on its protection contributions to exist. That said, chemical weapons have not been used against U.S. forces since World War I. Even the massive and world-altering destruction that included nuclear weapons during World War II did not see their usage, despite many parties stockpiling vast quantities of these weapons.³ Iraq had more chemical weapons than just about anyone, and Saddam Hussein had a history of using them, yet he chose to watch the destruction of his military during Desert Storm rather than use them against the United States.⁴ The 2022 Russian invasion of Ukraine currently raging in Europe with hundreds of thousands of casualties has not seen the employment of chemical weapons on a significant scale, although Ukraine has accused Russia of using riot control agents outside of internationally recognized legal uses.⁵ With regard to U.S. decision-making, it is relevant to note that this usage has been against a nonnuclear power.

As a result of this relevance challenge, the Chemical Corps struggles to make its case as a maneuver support branch as maneuver commanders quite regularly ignore their chemical officers’ technical contributions. Those officers are usually relegated to roles that are general in nature such as preparing the monthly Unit Status Report. CBRN tasks are often at the bottom of most units’ training prioritization, and Army Regulation 350-1, Army Training and Leader Development, removed “mandatory” status from CBRN tasks in 2025, so this trend will likely continue.⁶ The few times that CBRN training input is indulged is to prepare a unit for chemical threats from highly artificial scenario injects during combined training center (CTC) rotations. Even then, those injects primarily involve individual soldier tasks such as donning a mask. A CBRN officer does not need to teach that, and it does not require a specialized CBRN NCO to inventory and conduct basic mask maintenance.

Soldiers from the 36th Engineer Brigade train for a defense support of civil authorities mission as members of the Defense Chemical, Biological, Radiological, Nuclear Response Force on 18 February 2019 at Fort Hood, Texas. (Photo by 2nd Lt. Corey Maisch, U.S. Army)

Decontamination is reliant upon massive amounts of water in theater, which is often difficult to find in many operational environments, and even so, it does not require a specialized chemical officer to find a spot on the map where the main supply route intersects a stream as a potential decontamination location.⁷ Of course, any military operation requires thorough planning, but an entire specialized Army CBRN battalion headquarters is not required to plan, execute, and oversee spraying trucks with an M26 decontamination apparatus. Regarding CBRN reconnaissance, the future of chemical threat detection is becoming more and more unmanned and autonomous, and the technology will likely not require specialized soldiers for operation. Will we really need a specialized CBRN soldier managed by a unique Army branch to fly a drone that happens to carry a chemical sensor?⁸

Additionally, the American corporate and industrial base has a massive amount of expertise, equipment, education and experience that could be made available to the military should a future threat require; simply input “chemical suits for sale” into the nearest internet search engine to see the tip of the iceberg.

All of this said, there is value in maintaining aspects of the core competencies of the Chemical Corps within the Army’s force structure. There is institutional knowledge and equipment that should be maintained in the event they are needed. The issue at hand is not whether the Army should have a CBRN military occupational specialty (MOS) to do certain CBRN tasks; the issue is whether an entire Army branch is needed to manage one officer MOS, one warrant officer MOS, and only one enlisted MOS. The Army should retain a small CBRN nucleus around which more could be built if the threat dictated. However, in the increasingly cost-conscious culture of the Department of Defense and the constant battle for billets, the existence of a separate and sovereign Chemical Branch with its administrative overhead to manage and oversee a separate Chemical Corps is no longer necessary. The overhead costs in money and positions to maintain a branch whose assigned capabilities are consistently sidelined by maneuver commanders, who we all ultimately work for, are not justifiable.

The best way forward for the Army is for the Chemical Branch apparatus to be deconstructed, with key elements of the Chemical Corps being absorbed by the Engineer Regiment. When this happens, our former Chemical Branch CBRN soldiers will become CBRN engineers, managed by the Engineer Branch as full-fledged members of the Engineer Regiment. There are many reasons why this action would be in everyone’s best interests.

Upward Mobility and Talent Retention

If CBRN officers and NCOs were engineer officers and NCOs, they would have access to all the same opportunities as current engineers, up to the forty active-duty O-6-level commands that are exclusively for engineer officers. For comparison, there are only five enduring active-duty CBRN O-6-level commands. Former CBRN officers and soldiers would benefit from increased advocacy, a larger voice with the other branches and the Army writ large, and a massively wider range of career progression options if they simply became engineer soldiers. For the engineers, the inclusion of the former CBRN officers would expand the talent pool from which to eventually select its O-6-level commanders, most of whom serve in the USACE districts, which can be difficult to fill due to the sheer quantity.

Location, Location, Location

Fort Leonard Wood, Missouri, is already home to both the Engineer and Chemical Regiments. Their shared center of excellence, Maneuver Support, is in the same building as their respective schoolhouse commandants. They both have their basic training and Advanced Individual Training at Fort Leonard Wood. The integration of the Chemical Regiment and its assets into the Engineer Regiment would be relatively simple from a logistical and cost-effective perspective.

A History of Collaboration

As stated earlier, the brigade engineer battalion design included the BCT’s only chemical unit, the chemical reconnaissance platoon. Going farther back in time, engineer battalions have often held chemical companies, such as the 71st Chemical Company within the 65th Engineer Battalion at Schofield Barracks, and the old brigade special troops battalion construct, which was often commanded by an engineer but included CBRN soldiers and capabilities. At CTC rotations, it is often the engineers who pick up operational control of whatever chemical units join the training.

Another example of the continued relationship between the CBRN and engineer communities exists in a high profile CBRN readiness priority: the Defense CBRN Response Force mission, which is often tasked to an engineer brigade to oversee and execute if called upon.⁹ Finally, some of our closest military allies, the United Kingdom and Australia, have already incorporated their chemical forces inside of the Corps of Royal Engineers and the Special Operations Engineer Regiment, respectively.¹⁰ If the U.S. Army were to do the same, we would simply be aligning our structure with that of our key partners.

Economy of Scale

While the Army does need some tactical-level CBRN knowledge and capabilities on standby, it does not need the bureaucratic overhead of a unique branch to provide them. Every Army branch has its necessary bureaucracy to fulfill the full range of doctrine, organization, training, materiel, leadership and education, personnel, facilities, and policy requirements, but we would gain efficiencies if we combined a small branch with a larger one and simply added the traditional CBRN tasks and responsibilities to the engineer repertoire. A reduction in the number of branches would also streamline the adoption and integration of the new formation-based layered protection concept that the Maneuver Support Center of Excellence has recently undertaken.¹¹

Overlap of Technical Expertise

There are many kinds of academic engineering fields including civil engineering, mechanical engineering, electrical engineering, environmental engineering, and even chemical engineering. Many officers who pursue the Engineer Branch in the Army have a science, technology, engineering, or math (STEM) educational background. This STEM background is often what tilts an officer toward the branch in the first place. Chemical officers often choose their branch for similar reasons. Degrees in chemistry, biology, and chemical engineering are common among these officers and often have significant crossover with engineer officers. For example, the author of this article has a biology undergraduate degree. While the Engineer Corps and Medical Service Corps were his first and second choices respectively, the Chemical Corps was his third because of his education. Most newly commissioned lieutenants who are branched engineer or chemical could easily swap branches with a minimal loss in capability to the Army. While equal in the beginning, however, the engineers have a clear advantage in career potential due to the factors already discussed. We need to change that.

Integration at the Soldier Level

The engineers could easily absorb the CBRN soldiers and capabilities if we focus on the soldiers and organize their capabilities appropriately with the needs of the Army.

Australian soldiers from the 2nd Combat Engineer Regiment decontaminate infantry soldiers from the 8/9th Battalion, Royal Australian Regiment, during chemical, biological, radiological and nuclear weapons training on 25 June 2018 as part of Exercise Hamel at the Shoalwater Bay Military Training Area, Australia. The Australian Army has incorporated its chemical forces inside of their Special Operations Engineer Regiment. (Photo by Cpl. Tristan Kennedy, Australian Defence Force)

The Engineer Regiment and its culture have a proven history of respecting a variety of engineering niches. Every engineer lieutenant begins his or her career with multiple career track options, with the ability to switch between those options to find something they are good at and enjoy. A combat engineer platoon leader may later be a company commander of a construction company and choose to specialize in military construction. Later, that officer may seek time in USACE to serve as a project or program manager and ultimately command a USACE district at the O-5 or O-6 level. As an opposite example, an officer may be a construction platoon leader and then a sapper company commander, leading the officer to then choose to pursue all things combat and ultimately become a tactical engineer brigade commander working for an armored division. The engineers also have niche professions that officers choose such as the geospatial and engineer diver communities. CBRN engineers could be one more niche. Engineer officers could serve as a chemical reconnaissance platoon leader, but that officer could later command a sapper company. Similarly, if a former construction platoon leader wants to command a different kind of unit, a newly branded CBRN engineer company that focuses on decontamination could be available as a later option. The Engineer Branch is used to facilitating career tracks that are varied and range from generalists to specialists, with all being equally respected and encouraged.

There are myriad possible courses of action to facilitate such an integration, and there will be much argument as to the best way. Generally speaking, the big moves would be a transformation of the 74A CBRN officers into 12A engineer officers with all of the opportunities and responsibilities therein. The 74D soldiers and 740A warrant officers could be rebranded as CBRN engineers and CBRN engineer warrant officers, respectively, and within the 12-series. The high-end CBRN technical expertise could be retained in the warrant officer population and would form the primary nucleus of CBRN-specific knowledge and experience around which the Army could rapidly expand should a future threat require.

The establishment of a CBRN additional skill identifier (ASI) could be created and indicated by a wearable badge that would be earned through the completion of a rigorous CBRN curriculum, training an engineer soldier of any MOS in the most militarily relevant and mission-critical elements of the CBRN mission. Specifically, the use of CBRN equipment, techniques for operating in CBRN environments, decontamination, reconnaissance, and some field tactical application of these elements would be the focus of this ASI. Other elements of current CBRN training such as hazardous materials, disease identification, and nuclear mapping could be reduced or excluded as there are already civilian schools that provide certification in these topics that could be leveraged on a case-by-case basis.

Similar models for this ASI-based approach already exist. One is the Engineer Explosive Ordnance Clearance Agent (EEOCA) course. Although it is not as specialized or technically rigorous as the explosive ordnance disposal certifications, it provides a 90 percent solution for many explosive hazards a unit may face. When a unit needs the real expert, they call explosive ordnance disposal, but the EEOCA ASI can get them to the objective. In a CBRN scenario, if a unit needs the real expert, they could call the CBRN engineer warrant officer, but the CBRN engineer ASI could get them to the objective.

Integration at the Unit Level

Regarding force structure realignment options, the newly branded engineer CBRN companies and detachments could become organic to tactical units in the operational Army as part of the engineer force and therefore directly report to and work for a maneuver echelon like the engineers already do. Currently, the one operational active-duty CBRN brigade, 48th CBRN Brigade, leads four CBRN battalions spread across the country without a direct linkage to maneuver, further relegating them to the sidelines.¹² Even worse, the companies in each battalion are further scattered across the country, leaving a third of the 48th’s companies as direct reporting units to higher headquarters that are not collocated while residing on installations whose primary corps or division maneuver command doesn’t have a direct relationship to the CBRN companies. This is why CBRN companies often end up looking for a higher headquarters to pick them up at CTC rotations, and that headquarters is often an engineer unit. The question becomes, What is the purpose of a CBRN battalion or a CBRN brigade at all? The official answer via their mission essential task list in the Army Training Network is primarily to coordinate various CBRN responses.¹³ However, the real answer is probably, at least partially, to have CBRN command and key development billets available to keep the Chemical Corps alive as a separate institution.

These CBRN battalion and brigade headquarters are unnecessary to ensure the operational capabilities of the Army; the echelons of action for CBRN capabilities are the platoon and company. An engineer battalion or brigade would be perfectly capable of coordinating a CBRN response if the soldiers and materiel in CBRN companies were organic units. The fact that the Defense CBRN Response Force mission is consistently tasked to engineer brigades validates this assessment. The new engineer CBRN companies should permanently be assigned to an engineer headquarters at the appropriate echelon for the capability. With this, clear habitual relationships for training integration could be developed with the maneuver formations. For example, a newly branded engineer hazard response CBRN company could be assigned to the 36th Engineer Brigade, which will soon be the engineer brigade for the 1st Cavalry Division. That company could have its subordinate platoons develop habitual training relationships with the maneuver BCTs. Maneuver units can be finicky about incorporating nonmaneuver into training, but if there are local, organic relationships with these niche units, they are much more likely to involve others, benefiting everyone. In addition, if all current CBRN soldiers became engineers by branch, then any career progression concerns caused by eliminating the CBRN battalion and brigade headquarters would become irrelevant due to the many O-5 and O-6 engineer commands that would become newly available to the former CBRN soldiers.

A Call for Action

Understanding that the proposition presented here will meet resistance from both the chemical and engineer communities, it is important to focus on the desired end state: an efficient, capable and future-aligned Army. All organizations are inherently resistant to change, and this would be no different. However, the status quo is suboptimal. With the omnipresent reality of Army force reductions, we must find efficiencies wherever we can while still retaining capabilities the Army will need. We have many good CBRN officers and soldiers who are limited by the siloed structure they operate within and by the low prioritization of their trained tasks. Those tasks will be prioritized even lower as the new Army Regulation 350-1 guidance is implemented. The engineers are the most logical home for the Army’s CBRN capabilities with opportunities for all if integration is pursued. The Army has modified its organizational structure many times through the years when it made sense and when efficiencies could be found. Welcoming the “Dragon” soldiers into the engineer family meets these criteria and the sooner, the better for everyone.

Notes

1. Army Techniques Publication (ATP) 3-34.22, Engineer Operations—Brigade Combat Team and Below (U.S. Government Publishing Office [GPO], April 2021), chap. 2, https://armypubs.army.mil/epubs/DR_pubs/DR_a/ARN32097-ATP_3-34.22-000-WEB-1.pdf.
2. Joseph Clark, “Defense Official Says U.S. Will Continue to Lead in Chemical Weapons Disarmament,” DOD News, 29 September 2023, https://www.defense.gov/News/News-Stories/Article/Article/3543452/defense-official-says-us-will-continue-to-lead-in-chemical-weapons-disarmament/.
3. “History of United States’ Involvement in Chemical Warfare,” DOD Environment, Safety & Occupational Health Network and Information Exchange, updated 7 October 2024, https://www.denix.osd.mil/rcwmprogram/history/.
4. W. Andrew Terrill, “Chemical Warfare and ‘Desert Storm’: The Disaster That Never Came,” Small Wars & Insurgencies 4, no. 2 (1993): 263–79, https://doi.org/10.1080/09592319308423050.
5. John C. Tramazzo, “Ukraine Symposium – Russia’s Use of Riot Control Agents in Ukraine,” Lieber Institute, 17 May 2024, https://lieber.westpoint.edu/russias-use-riot-control-agents-ukraine/.
6. Todd South, “Army Slashes Mandatory Training Requirements with Regulation Update,” Army Times, 3 April 2025, https://www.armytimes.com/news/your-army/2025/04/03/army-slashes-mandatory-training-requirements-with-regulation-update/; Army Regulation 350-1, Army Training and Leader Development (U.S. GPO, 1 June 2025), 97–98, https://armypubs.army.mil/epubs/DR_pubs/DR_a/ARN44161-AR_350-1-001-WEB-2.pdf.
7. ATP 3-11.74, Chemical, Biological, Radiological, and Nuclear Platoons (U.S. GPO, 15 April 2021), 6-2–6-3, https://armypubs.army.mil/epubs/DR_pubs/DR_a/ARN32065-ATP_3-11.74-000-WEB-1.pdf.
8. Brian Feeney, “Army Researchers Work to Enable Chemical Threat Scanning on the Fly,” U.S. Army, 27 February 2025, https://www.army.mil/article/283396/army_researchers_work_to_enable_chemical_threat_scanning_on_the_fly.
9. Corey Maisch, “Soldiers Conduct Training for DCRF Mission,” Defense Visual Information Distribution Service, 18 February 2019, https://www.dvidshub.net/image/5177633/soldiers-conduct-training-dcrf-mission.
10. “Corps of Royal Engineers,” U.K. Army, accessed 7 July 2025, https://www.army.mod.uk/learn-and-explore/about-the-army/corps-regiments-and-units/engineering/corps-of-royal-engineers/; “RAF Honington,” Royal Air Force, accessed 22 July 2025, https://www.raf.mod.uk/our-organisation/stations/raf-honington/; Belinda Culley and Dominic Williams, “Sappers Share Their Specialist Skills,” Australian Defence Force, 15 November 2023, https://www.defence.gov.au/news-events/news/2023-11-15/sappers-share-their-specialist-skills.
11. Mark Pomereau, “Project Convergence Headed to Indo-Pacific Command in April,” Defense Scoop, 11 March 2025, https://defensescoop.com/2025/03/11/project-convergence-capstone-5-indo-pacific-command-army/; Ashley Roque, “Army Chief Mulls Project Convergence’s Future, with Industry Mixed on Event’s Value,” Breaking Defense, 24 March 2025, https://breakingdefense.com/2025/03/army-chief-mulls-project-convergences-future-with-industry-mixed-on-events-value/; “Formation Based Layered Protection (FBLP),” SAM.gov, 24 January 2025, https://sam.gov/opp/16bf69fc00fb4d55bf92702e68902a4f/view.
12. “48th Chemical Brigade,” U.S. Army Fort Hood, accessed 7 July 2025, https://home.army.mil/hood/units-tenants/48th-chemical-brigade.
13. Training and Evaluation Outline Report, Task Number 03-BN-0008, “Coordinate CBRN Response Operations” (Army Training Network, 18 July 2024 [CAC required]), https://atn.army.mil/ATNPortalUI/task/.

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