Chemical Weapon Stockpile Destruction: Pueblo, CO
In May 2006, “US Chemical Demilitarization: Expansion and Update” explained the underlying structure of the U.S. Army Chemical Materials Agency’s programs to safely store and dispose of chemical weapons. The CMA is responsible for a number of locations, each of which has its own prime contractor. Prime contractors hold the design, build, operation and closure portions of the contract, while subcontractors to the prime contractors vary by site. “Nerve Gas Stockpile Destruction at NECD in Newport, IN” shone a spotlight on one site’s efforts and contracts.
The U.S. Army’s Pueblo Chemical Depot in Colorado is another such site, which currently stores 2,611 tons of mustard agent contained in 155mm and 105mm artillery shells, and 4.5″ mortar shells. Decontamination is supervised by the PM Assembled Chemical Weapons Alternatives (ACWA), using a biochemical process rather than incineration; the CMA is still responsible for safe storage until the munitions can be decontaminated. This article discusses mustard agent’s effects and place in the history of warfare, and takes a look at the efforts underway to destroy the Pueblo stockpile between 2015-2023. An effort that recently featured a contract worth over half a billion dollars…
- Mustard Gas: A Quick Primer
- The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP)
- Contracts and Key Events
- Additional Readings
Mustard Gas: A Quick Primer
Mustard gas gained infamy in World War 1, when it was fired by German artillery during the battle of Ypres. This heavier-than-air “gas” is actually a finely-dispersed liquid that settles on people caught within it or falls to the ground, where it can remain active for days to months depending on conditions. Within 6 to 24 hours of exposure, victims experience intense itching and skin irritation. This gradually turns into painful, slow-healing chemical burns, characterized by large blisters filled with yellow fluid wherever the mustard agent contacted the skin. Eye irritation can be severe enough to cause temporary blindness, and vomiting is noted as a common symptom. Severe exposure can strip the mucous membranes from one’s bronchial tubes, causing respiratory system bleeding and blistering.
Though it was not designed as a killing agent, the respiratory effects of a high enough dose will result in a painful, lingering, choking death that could take 4-6 weeks to run its ghastly course. Even less-than-lethal doses generally require long periods of treatment, which effectively remove the affected soldier from the battle or even the war. Nor do the effects stop there. Mustard agent is strongly mutagenic, which makes it a potent trigger for cancer (carcinogen) in later life.
Mustard agent stockpiles were high on all sides as World War 2 broke out, and it is believed that it would have been used if Hitler’s Germany had invaded Britain. During that war, US President Franklin Delano Roosevelt’s June 8, 1943 speech informed Hitler that any use of chemical weapons on the battlefield would be followed by the chemical bombing of German cities. With a stockpile of over 77,000 tons on hand, mustard agent would have comprised the bulk of any American retaliation.
Unlike nerve gas, which was developed by Germany during World War 2 and refined during the Cold War, mustard agent has no known antidotes.
Early chemical weapons use was part of Soviet military doctrine, but the Soviet Empire’s defeat without a major war prevented either its chemical stockpiles, or NATO retaliation, from being put to the test on the battlefields of Europe.
That did not entirely prevent the use of mustard agents in warfare. After World War 2, it has been used in wars fought by Egypt against North Yemen (1963-1967) and Saddam Hussein’s Iraq against Iran (1983-1988). There are also reports of internal use by Sudan in the 1990s, during its civil war against the black and largely Christian south of the country. As yet, there are no similar reports from the government’s war against the black and largely Muslim population of Darfur, in Sudan’s west.
The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP)

As the map above shows, the plant will consist of 11 principal buildings spread across an 80-acre site. It is estimated that it will cost somewhere in the neighborhood of $3.5 billion over its projected 20-year life span. The plant’s engineering design package contains more than 5,000 individual documents in notebooks occupying 20 feet of shelf space, alongside a stack of drawings 4 feet high.
Fortunately, its basic concept is easier to describe. After being robotically drained from its munitions casing, the viscous mustard agent will be chemically neutralized by vigorous mixing with hot water and a caustic solution. This produces a biodegradable liquid byproduct known as hydrolysate. the hydrolysate then undergoes biotreatment by microbes that “digest” the organics in the solution, breaking them down into carbon dioxide and wet solids called biosludge. Says Bechtel Pueblo project manager Paul Henry:
“The engineering challenge is not in neutralizing the mustard; it’s in the mechanics of removing the explosives and draining the mustard out of more than half a million individual artillery and mortar shells.”
Bechtel’s project partners include Battelle Memorial Institute, Parsons, and Washington Group International subsidiary Washington Demilitarization Company.
Contracts and Key Events

Oct 17/08: Bechtel National Inc in San Francisco, CA received a $563.5 million cost plus incentive fee contract. “This modification is for the balance of construction of the Pueblo Chemical Agent Destruction Pilot Plant.”
Work will be performed in Pueblo, CO, with an estimated and completion date of Dec 31/23. Bids solicited were via the Web and 2 bids were received by the U.S. Army Sustainment Command in Rock Island, IL (DAAA09-02-D-0025).
May 22/07: ACWA announces [PDF] that the Pueblo Chemical Agent-Destruction Pilot Plant’s (PCAPP) final design has been accepted by the Us DoD, placing the program back on track.
Nov 1/04: The US DoD Inspector General issues “Pueblo Chemical-Agent-Destruction Pilot Plant Project – Report No. D-2005-009( – Project No. D2004AM-0180.000.” An excerpt from the summary:
“In September 2002, the Program Manager, through the contracting officer, awarded a $166.8 million contract to Bechtel National, Inc., San Francisco (Bechtel), to design the PCAPP facility. In January 2003, the Under Secretary certified to Congress that the neutralization of the assembled chemical munitions followed by biological-treatment was as safe and cost-effective as incineration and that the entire stockpile could be destroyed by 2010 for $1.5 billion in FY 2002 constant dollars. In May 2004, the Program Manager informed the Acting Under Secretary that, based on Bechtel’s 30 percent design submission, the life-cycle cost estimate had escalated to $2.65 billion, the estimated completion of operations to August 2011, the square footage of main processing buildings to 273,000 square feet, and the number of employees to approximately 890.”
The report is sharply critical of the project’s management, and makes a number of recommendations.
September 2004: The US DoD temporarily suspends design activities at Pueblo, and looks at ways to reduce the project’s cost. Some of Bechtel’s team members leave for other projects.

October 2002: ACWA is assigned responsibility for the destruction of chemical weapons stockpiles at Pueblo, and at Bluegrass, KY. The US Army’s Chemical Materials Agency remains responsible for safe munitions storage and care at those locations.
September 2002: Bechtel Pueblo is selected as the systems contractor to design, construct, systemize, pilot test, operate, and close the Pueblo Chemical Agent-Destruction Pilot Plant.
July 2002: ACWA chooses to destroy the Pueblo mustard agent stockpile using an approach of neutralization, followed by biotreatment.
June 2002: ACWA shifts its focus from assessing chemical weapons disposal technologies to implementing full-scale pilot testing of alternative technologies at these sites. As a result, the program changed its name from Assembled Chemical Weapons Assessment to Assembled Chemical Weapons Alternatives (still ACWA).
2000: ACWA tests 3 more technologies, and determines that 4 of them are viable for pilot testing. That year, a law requires the US Department of Defense (DoD) to consider incineration and any demonstrated ACWA technologies for disposal of the Pueblo, CO stockpile.
1999: Congress authorizes ACWA to manage the development and pilot-scale testing of these technologies. ACWA successfully demonstrates 3 technologies in 1999.
1997: Congress establishes the Assembled Chemical Weapons Alternatives program (ACWA) to safely test and demonstrate at least 2 alternative chemical weapon disposal technologies, which might supplement or replace the standard incineration process.
Aug 5/96: Booz-Allen & Hamilton, Inc. in Mclean, VA wins an indefinite-delivery/ indefinite-quantity contract with firm-fixed-price/ cost plus fixed fee elements with a base period and 4 option periods. The contract has an estimated cumulative total of up to $30 million. The firm will provide program and integration support for the program manager for chemical demilitarization. They will prepare, review, revise, and validate public outreach documentation, public outreach tools, public outreach studies; and establish and maintain public outreach offices in the vicinity of chemical demilitarization sites.
Work will be performed in McLean, VA and the Unites States unitary chemical stockpile sites throughout the Continental United States (Aberdeen Proving Ground, MD; Anniston Army Depot, AL; Blue Grass Army Depot, KY; Newport Army Ammunition Plant, IN; Pine Bluff Arsenal, AK; Pueblo Depot Activity, CO; Tooele Army Depot, UT; and Umatilla Depot Activity, OR), and is expected to be complete by Aug 5/01. There was an announcement in the Commerce Business Daily on Sept 29/95, and 9 bids were received by the U.S. Army Chemical and Biological Defense Command at Aberdeen Proving Ground, MD (DAAM01-96-D-0011).
Aug 5/96: Science Applications International Corporation, Research and Development Company in San Diego, CA wins an indefinite-delivery/ indefinite-quantity contract with firm-fixed-price/ cost plus fixed fee elements with a base period and 4 option periods. The contract has an estimated cumulative total of up to $30 million.
In exchange, SAIC will provide program and integration support for the program manager for chemical demilitarization, program management, integration and site support services. They will review, prepare, revise and maintain program management documentation; and offer program monitoring and analyses; meetings and briefing support field offices services; site monitoring and analysis, site specific; documentation preparation and review; project management support, technical studies , testing services, quality assurance services; laboratory and monitoring services, and environmental compliance.
Work will be performed in San Diego, CA and Abingdon, MD and is expected to be complete by Aug 5/01. There was an announcement in the Commerce Business Daily on Sept 29/95, and 3 bids were received by the U.S. Army Chemical and Biological Defense Command at Aberdeen Proving Ground, MD (DAAM01-96-D-0012).
July 12/96: Science Applications International Corporation Research & Development Company in San Diego, CA wins an indefinite-delivery/ indefinite-quantity contract with firm-fixed-price/ cost plus fixed fee elements with an estimated cumulative total of up to $60 million. SAIC will provide program and integration support for the program manager for chemical demilitarization. They will analyze, investigate, review and validate demilitarization technologies, equipment and processes; perform risk analyses, quality assurance, audits, inspections, industrial chemical and pollutant monitoring services, reports and surveys; offer safety, security and chemical surety services; and develop and conduct training, plans, manuals, programs and operations, surveys and audits.
Work will be performed in San Diego, CA; Aberdeen Proving Ground, MD; and the United States military stockpile sites throughout the Continental United States (Aberdeen Proving Ground, MD; Anniston Army Depot, AL; Blue Grass Army Depot, KY; Newport Army Ammunition Plant, IN; Pine Bluff Arsenal, AK; Pueblo Depot Activity, CO; Tooele Army Depot, UT and Umatilla Depot Activity, OR), and in the Pacific (Johnston Atoll). Work is expected to be complete July 12/01. This was a broad agency announcement in the Commerce Business Daily on Sept 29/95, and 4 bids were received by the U.S. Army Chemical and Biological Defense Command at Aberdeen Proving Ground, MD (DAAMO1-96-D-0009).
Additional Readings
- US Center for Disease Control – Sulfur Mustard (Mustard Gas)
- US DoD ACWA – U.S. Chemical Agent and Munitions Stockpiles Map [PDF, 2.5MB]. Shows locations of stockpiles, with descriptions of the destruction technology chosen and agent type stored/destroyed at each site.
- US Army – Program Manager Assembled Chemical Weapons Alternatives.
- US DoD ACWA – Assembled Chemical Weapons Alternatives Program Legislation [PDF, 320k, as of May 2008]
- Colorado Department of Public Health and Environment, Hazardous Materials and Waste Management Division – Pueblo Chemical Depot Colorado Chemical Demilitarization Program. Includes extensive public records related to the project.
- Bechtel – Pueblo Chemical Agent Destruction Pilot Plant
- US DoD ACWA (June 18/08) – Pueblo: A Partnership for Safe Chemical Weapons Destruction” [PDF, 480k], which provides an overview of the chemical weapons destruction program in Pueblo including technology, the pilot plant and public outreach efforts.
- US DoD ACWA (Sept 24/07) – Pueblo Designs for success [PDF, 728k]. Offers a detailed description of the project approaches taken after the September 2004 suspension of design activities at Pueblo, leading up to the May 2007 PCAPP design approval.
- US DoD Inspector General (Nov 1/04) – Pueblo Chemical-Agent-Destruction Pilot Plant Project – Report No. D-2005-009 – Project No. D2004AM-0180.000.