Pueblo Chemical Agent-Destruction Pilot Plant

The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) is a chemical weapons destruction facility that has been built to destroy the chemical weapons stockpile at the Pueblo Chemical Depot, in southeastern Colorado. The depot contains munitions that are part of the U.S. national chemical weapons stockpile. Before chemical weapons disposal began at PCAPP, these munitions contained 2,613 U.S. tons of mustard agent. The weapons have been stored at the 23,000-acre (93 km²) depot since the 1950s.

PCAPP logo

Aerial view of the plant

Destruction of this stockpile is a requirement of the Chemical Weapons Convention, an international treaty to which the United States is a party. The Organisation for the Prohibition of Chemical Weapons is the implementing body of the Chemical Weapons Convention and monitors the progress of the nation's chemical weapons destruction programs.

The Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA) oversees the destruction of the Pueblo chemical weapons stockpile.

Bechtel Pueblo Team (BPT; consisting of Bechtel National, Inc., AECOM and Battelle Memorial Institute) will design, construct, pilot test, operate and close PCAPP.

Planning of activities

Destruction began in 2016 and the plant will operate until all the chemical weapons have been destroyed and closure activities (shut-down, dismantling, and restoration of site) have been completed. Elimination of chemical weapons/agent is slated for 2023.[1]

In 2010, the Pueblo Chemical Depot, in conjunction with the ACWA program, completed an environmental assessment (EA) to meet the requirements of the National Environmental Policy Act, or NEPA, and Title 32 Code of Federal Regulations Part 651[2] regarding the construction and operation of the U.S. Army’s Explosive Destruction System (EDS) and/or other explosive destruction technologies (EDT), at the U.S. Army Pueblo Chemical Depot in Colorado.[3] The EA was withdrawn and a new EA was completed in 2012.[4] The new EA focused on the use of EDT for destroying overpacked and reject munitions.[5] In April 2013, Program Executive Officer Conrad F. Whyne announced his selection of EDS to augment the Pueblo Chemical Agent-Destruction Pilot Plant for the safe destruction of chemical munitions unsuited for processing by the main plant’s automated equipment.[6] In spring 2018, the decision was made to end EDS and utilize three Static Detonation Chamber units to augment the site.

History of chemical demilitarization in Colorado

Decade	Milestones
1950s [7]	Pueblo Ordnance Depot (later redesignated as the U.S. Army Pueblo Chemical Depot) begins storage of chemical weapons containing mustard agent.
1980s[8]	Public Law 99-145 designates the U.S. Army responsible for the destruction of the U.S. chemical weapons stockpile.
1990s[9]	The United States Congress establishes the ACWA program under the Department of Defense to identify and demonstrate alternatives to incineration. Congress ratifies the Chemical Weapons Convention treaty, which directs all member nations to destroy their chemical weapons and production facilities.
2000s	Department of Defense selects neutralization followed by biotreatment as the destruction method for the Colorado stockpile. The Bechtel Pueblo Team is awarded a contract to design, build and operate PCAPP. PCAPP Groundbreaking is held. Design work and preliminary construction is suspended pending evaluation of cost reduction measures. PCAPP redesign is approved by the Department of Defense and construction work resumes. The Secretary of Defense affirms to Congress that there are no options by which the U.S. can destroy 100 percent of its chemical stockpile by the extended Chemical Weapons Convention treaty deadline of April 29, 2012. The Department of Defense accepts the final design for the Pueblo Chemical Agent-Destruction Pilot Plant. Above ground vertical construction begins with erection of the Multipurpose Building. Public Laws 110-116 and 110-181 are enacted, mandating destruction of the chemical stockpile by April 2012 or in no case later than December 31, 2017. PCAPP receives the U.S. Department of Labor Occupational Safety and Health Administration Voluntary Protection Program Star Status award in recognition of safety excellence. PCAPP construction is more than halfway complete, with interior and exterior work ongoing in multiple buildings, including the Agent Processing Building, Control and Support Building, Enhanced Reconfiguration Building, Biotreatment Electrical Building, Entry Control Facility, Immobilized Cell Bioreactor and Off-gas Foundation Pads and Munitions and Energetic Service Magazines[10].
2010s	Construction continues with interior and exterior work ongoing in multiple buildings, including the Agent Processing Building, Control and Support Building, Enhanced Reconfiguration Building, Biotreatment Electrical Building, Multipurpose Building, Filter Press Building, PCAPP Medical Clinic, Entry Control Facility, Laboratory Facility, Immobilized Cell Bioreactor, Brine Reduction System, Off Gas Foundation Pads and Munitions and Energetics Service Magazines. The systemization phase begins at the PCAPP. Construction teams turn over the first subsystems to the start-up groups for systemization testing and commissioning to begin to prepare the facilities for chemical weapons destruction operations. To meet the requirements of the NEPA and Title 32 Code of Federal Regulations Part 651, ACWA, in conjunction with the U.S. Army Pueblo Chemical Depot, completes an environmental assessment regarding the possible use of explosive destruction technologies in Pueblo. Following a public comment period and extensive review by Department of Defense leadership, the environment assessment is withdrawn. As part of systematizing the facility, Assembled Chemical Weapons Alternatives Test Equipment, or ATE, arrives for practice and training use. PCAPP is formally notified by the U.S. Department of Labor's Occupational Safety and Health Administration (OSHA) that the PCAPP project was re-certified as a Star Worksite under OSHA's Voluntary Protection Program. In April 2012, Pueblo Chemical Depot and ACWA completed an environmental assessment to meet the requirements of the NEPA, and Title 32 Code of Federal Regulations Part 651, to address any potential impacts of the installation and operation of explosive destruction technology at the depot. The environmental assessment concluded that the installation and operation of an explosive destruction technology will have no significant environmental impacts. A draft Finding of No Significant Impact was prepared and provided for public comment for a 60-day period. It was concluded that no additional analysis was necessary for the proposed action under NEPA. On December 12, 2012, PCAPP declares construction complete and moves into the systemization phase of the project.[11] On April 18, 2013, Program Executive Officer Conrad F. Whyne announces his selection of the U.S. Army’s Explosive Destruction System (EDS) to augment PCAPP. The decision followed a lengthy review of several explosive destruction technologies designed for the safe destruction of chemical munitions unsuited for processing by the main plant’s automated equipment.[6] Construction began and was completed on the PCAPP EDS site, located at the U.S. Army Pueblo Chemical Depot in 2014. The first of two EDS units arrived on site, aligning with the completion of specially-designed environmental enclosures that will house the EDS units for added protection. Provisional Operations, a two-month period in which operations and maintenance staff practice training with simulated munitions and agent, began at the PCAPP in 2014. This extensive training is conducted on a large-scale to ensure employees are better prepared for plant operations. Chemical stockpile destruction in Colorado was initiated on March 18, 2015, by the EDS, located on the U.S. Army Pueblo Chemical Depot near the PCAPP. This event marked the first step towards eliminating the final 10 percent of the U.S. chemical weapons stockpile. In 2015, the Bechtel Pueblo Team earns recertification of Star Status in the OSHA's Voluntary Protection Program.[12] On Feb. 11, 2016, the EDS successfully completed its first destruction campaign, eliminating 265 105 mm projectiles, 196 155 mm projectiles, 88 4.2-inch mortar rounds and 11 Department of Transportation bottles for a total of 560 munitions.[13] Systemization was completed and operations began on Sept. 7, 2016. On Sept. 7, 2016, operations began at the PCAPP. The plant began destroying the stockpile of chemical weapons at the U.S. Army Pueblo Chemical Depot in Colorado. The plant is utilizing neutralization followed by biotreatment as the technology to destroy munitions containing more than 2,600 tons of mustard agent. Additionally, the Army’s EDS, is on stand-by to augment the main plant to destroy problematic chemical munitions that cannot be easily processed using its automated equipment.[14] PCAPP operations were paused on Nov. 20, 2016 due to an industrial hazardous waste spill of approximately 450 gallons of hydrolysate. The spill was associated with a seal failure of one of the agitators located on the side of a hydrolysate storage tank. On Nov. 23, an unrelated, second issue was discovered; rainwater had leaked through the liner of the secondary containment system surrounding the Brine Concentrator Feed Tanks. These tanks hold the effluent produced in the Immobilized Cell Bioreactors and are essential to the operation of the biotreatment process.[15] PCAPP operations resumed on Jan.12, 2017. Under the purview of the Colorado Department of Public Health and Environment, the agitators were removed from one of the hydrolysate storage tanks, and the openings were sealed with blind flanges. Additionally, the liners, from the floor and part way up the walls of the secondary containment system around Brine Concentrator Feed Tanks were removed.[16] On April 27, 2017, the Biotreatment Area at the Pueblo plant began processing hydrolysate, which is the product of the neutralization of mustard agent. From July to September 2017, PCAPP temporarily shipped wastewater off site for treatment and disposal at the Veolia Environmental Services Hazardous Waste Incinerator, in Port Arthur, Texas. The wastewater, known as hydrolysate, is the product of the neutralization of chemical agent at the plant. A total of 52 truckloads safely transported 236,473 gallons to Veolia for disposal.[17] In September 2017, PCAPP marked its first full year of the pilot testing phase in which the plant destroyed 253 U.S. tons of mustard agent and 42,897 155mm projectiles. On Sept. 8, 2017, agent destruction operations were paused at PCAPP due to higher than anticipated amounts of solids being washed out of munitions and clogging agent neutralization systems. On Feb. 15, 2018, PCAPP ordnance technicians reached a plant milestone[18] when the last of more than 28,000 105mm projectiles went through Baseline Reconfiguration. On April 12, 2018, PCAPP ordnance technicians started the Baseline Reconfiguration process for the 4.2-inch mortar rounds[19]. At the end of this campaign, more than 97,000 of these rounds will have undergone this process. On June 12, 2018, agent destruction operations resumed[20] after required modification to the Agent Neutralization Reactors were completed. On Nov. 13, 2018, PCAPP moved one step closer to full operations when the staff initiated Integrated Facility Demonstrations. Within the first 24 hours, the plant experienced its highest throughput, the rate at which munitions are processed, to date. [21] IFDs successfully concluded on May 3, 2019. On April 1, 2019, PCAPP announced the achievement of a significant milestone - the elimination of a quarter (25%) of the mustard agent stockpiled in chemical weapons in the Pueblo Chemical Depot[22]. In May 2019, PCAPP successfully completed the third and final round of background sampling for pilot testing.[23] In July 2019, PCAPP exceeded destruction of half the 155mm projectiles in the Pueblo Chemical Depot stockpile. [24]
2020s	In February 2020, PCAPP exceeded destruction of half of the agent stored at the Pueblo Chemical Depot stockpile.[25] On June 23, 2020, PCAPP ordnance technicians completed the Baseline Reconfiguration process for the 4.2-inch mortar rounds.[26]

Technology

The Department of Defense conducted studies[27] to evaluate potential impacts of the elimination of these weapons using incineration and non-incineration methods. Four technologies were considered:

• incineration
• chemical neutralization followed by supercritical water oxidation
• chemical neutralization followed by supercritical water oxidation and gas phase chemical reduction
• electrochemical oxidation

Neutralization followed by biotreatment was selected for the destruction of the Colorado stockpile.

The technology comprises the following steps:[28]

• Robotic equipment removes energetics (explosives) from the weapon, including the fuze and the burster. The energetics are disposed of at a permitted facility off site.
• The inside of the weapon is remotely accessed and mustard agent is washed out with high-pressure water.
• The mustard agent is mixed with hot water. The resulting mixture is neutralized with a caustic solution. The byproduct is called hydrolysate. The hydrolysate is treated biologically.
• The water is recovered for reuse in the destruction process and the excess activated sludge is secured in containers for disposal at an off-site permitted facility.
• Metal parts are heated to 1,000 °F (538 °C) for 15 minutes and are then recycled.

Explosive Destruction Technology (EDT)

After an assessment of problem munitions showed that their destruction would be difficult using neutralization and biotreatment, ACWA decided to explore use of Explosive Destruction Technology (aka Explosive Demolition Technology, Explosive Detonation Technology, EDT) for these projectiles.

EDT uses heat and pressure from explosion or just heat to destroy the munitions; it is not considered incineration and does not require disassembly of the weapons.[29] There are three general types of technologies that can destroy chemical weapons:

• Detonation technology – destroys the majority of the agent and explosive in the munition by detonating donor explosives wrapped around the munition. The resulting off-gasses are processed through secondary treatment to ensure agent destruction. Examples of detonation technology include the Transportable Detonation Chamber, or TDC, and the DAVINCH (Detonation of Ammunition in a Vacuum-Integrated Chamber).
• Neutralization technology – uses small explosive shaped charges to open the munition and consume the explosive in the burster and fuze. The agent is destroyed by subsequent neutralization. The U.S. Army’s EDS, is an example.
• Thermal destruction – uses the heat of the electrically heated containment vessel to deflagrate the munition and destroy the agent and energetics. The resulting gases are treated in an off-gas treatment system. The Static Detonation Chamber, or SDC, is an example of thermal destruction technology.

In April 2013, Program Executive Officer Conrad F. Whyne announced his selection of the U.S. Army’s EDS to augment the PCAPP for the safe destruction of chemical munitions unsuited for processing by the main plant’s automated equipment.[30]

The PCAPP EDS started processing on March 18 with the elimination of Department of Transportation (DOT) bottles which contain chemical agent drained from selected munitions over the years to assess the condition of the stockpile. On April 8, the first munitions were successfully processed. In June, operators at the PCAPP EDS took things up a notch with the introduction of 4.2-inch mortars into the destruction process. The first three mortars were joined by three 105 mm projectiles. All were safely detonated in the vessel on June 18. On July 16, the first 155 mm projectiles from Pueblo’s stockpile were safely destroyed in the PCAPP EDS. The PCAPP EDS completed its first campaign in February 2016, destroying 549 munitions that leaked or were sampled in the past and 11 bottles containing mustard agent. The second and final campaign ran from June 25 to Dec. 5, 2018 [31].  

Static Detonation Chamber (SDC)

In spring 2018, PCAPP announced a proposal to procure three Static Detonation Chambers (SDC).

Due to performance issues identified during the first year of pilot testing, and in order to complete destruction of the stockpile by 2023, this technology was chosen to augment the main plant under a proposal by the Assembled Chemical Weapons Alternatives program.[32] To meet the requirements of the National Environmental Policy Act and federal regulations, an Environmental Assessment was conducted. A Finding of No Significant Impact resulted from the assessment.[33]

Preparations at the SDC site began in June 2019.[34] The first Static Detonation Chamber components arrived at the depot on Aug. 6, 2019, in a convoy of more than a dozen flatbed trucks.[35] Assembly began Oct. 31, 2019. Protective, tension fabric coverings were erected around each unit, with construction beginning in September 2019. They were completed in June 2020.[36]

Public outreach

The Pueblo Chemical Stockpile Outreach Office was established in 1997 to serve as the community’s primary information resource on chemical weapons destruction in Colorado. The office responds to inquiries, provides information materials and coordinates guest speakers for a variety of different civic groups and organizations and interfaces with the governor-appointed Colorado Chemical Demilitarization Citizens’ Advisory Commission.

See also

• Pueblo Chemical Depot
• Pueblo Depot Activity

References

1. "PEO ACWA – Frequently Asked Questions".
2. "Summary of the National Environmental Policy Act". Epa.gov. Retrieved April 3, 2017.
3. "Pueblo Chemical Depot completes environmental assessment" (PDF). Peoacwa.army.mil. Retrieved 21 May 2018.
4. "New Path Forward Charted for Explosive Destruction Technologies at Pueblo Chemical Depot" (PDF). Peoacwa.army.mil. Retrieved 21 May 2018.
5. Program Executive Office, Assembled Chemical Weapons Alternatives. "Program Timeline". Peoacwa.army.mil. Retrieved April 3, 2017.
6. "Destruction of WWII-era Chemical Stockpile Set to Begin". March 13, 2019.
7. "U.S. Army Pueblo Chemical Depot | U.S. Army Chemical Materials Activity". Cma.army.mil. Retrieved 2017-09-26.
8. Program Executive Office, Assembled Chemical Weapons Alternatives (December 15, 2016). "Facts: PEO ACWA Program Legislation". Peoacwa.army.mil. Retrieved April 3, 2017.
9. "Archived copy" (PDF). Archived from the original (PDF) on 2017-06-21. Retrieved 2018-09-19.CS1 maint: archived copy as title (link)
10. "Program Timeline | Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA)". www.peoacwa.army.mil. Retrieved 2018-09-19.
11. "Chemical Demilitarization-Assembled Chemical Weapons Alternatives" (PDF). March 18, 2015. Retrieved September 26, 2017.
12. Program Executive Office, Assembled Chemical Weapons Alternatives (February 10, 2015). "Reaching for the Stars: PCAPP Recommended for Top OSHA Award". peoacwa.army.mil. Retrieved April 3, 2017.
13. "Explosive Destruction System Completes First Campaign, Program Timeline". Krdo.com. Retrieved 17 July 2016.
14. "Army Begins Destroying Chemical Weapons in Colorado". Military.com. Retrieved 22 May 2018.
15. KKTV (December 10, 2017). "Two incidents pause chemical weapons destruction". kktv.com. Retrieved April 3, 2017.
16. Program Executive Office, Assembled Chemical Weapons Alternatives. "Pilot Testing Resumes at Colorado Chemical Demilitarization Plant". peoacwa.army.mil. Retrieved April 3, 2017.
17. "First Off-Site Shipment of Wastewater Successful | Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA)". Peoacwa.army.mil. Retrieved 2017-09-26.
18. "Reconfiguration of Boxed 105mm Munitions Complete | Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA)". Peoacwa.army.mil. Retrieved 2018-03-28.
19. "Training Begins for 4.2-inch Mortar Rounds | Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA)". www.peoacwa.army.mil. Retrieved 2018-06-18.
20. "Agent Operations Resume at Pueblo Destruction Facility | Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA)". www.peoacwa.army.mil. Retrieved 2018-06-18.
21. "Plant Processing Rate High During First Demonstration Day".
22. "Pueblo Plant Achieves Chemical Agent Destruction Milestone".
23. "PCAPP Monthly Recap May 2019".
24. "Pueblo Plant Destroys 50% of 155mm Munition Stockpile".
25. "Pueblo Plant Destroys Half of Chemical Stockpile in Colorado".
26. "Baseline Reconfiguration of 4.2-inch Mortar Rounds Complete".
27. Council, National Research (16 August 2006). "Review and Assessment of the Proposals for Design and Operation of Designated Chemical Agent Destruction Pilot Plants (DCAPP-Pueblo): Letter Report". Nap.edu. doi:10.17226/11714. Retrieved 17 July 2016.
28. Geuss, Megan (February 26, 2017). "In southeastern Colorado, robots carefully disarm WWII-era chemical weapons". Arstechnica.com/. Retrieved April 3, 2017.
29. Program Executive Office, Assembled Chemical Weapons Alternatives. "Explosive Destruction System". peoacwa.army.mil. Retrieved July 3, 2017.
30. "Explosive Destruction System Selected to Augment Pueblo Chemical Agent-Destruction Pilot Plant" (PDF). peoacwa.army.mil. April 18, 2013. Retrieved January 7, 2019.
31. "Explosive Destruction System Begins Second Campaign | Program Executive Office, Assembled Chemical Weapons Alternatives (PEO ACWA)". www.peoacwa.army.mil. Retrieved 2018-09-19.
32. "Two Static Detonation Chambers Proposed to Treat Problematic Rounds".
33. "Press Release: No Significant Environmental Impacts to Result from Installation and Operation of Static Detonation Chambers at Pueblo Chemical Depot".
34. "Static Detonation Chamber Construction Begins at Pueblo Plant".
35. "First Static Detonation Chamber Components Arrive at Pueblo Plant".
36. "Pueblo Static Detonation Chamber Units Covered, Energized".

• "Program Executive Office, Assembled Chemical Weapons Alternatives Website". Department of Defense; Program Executive Office, Assembled Chemical Weapons Alternatives. Retrieved 2009-06-01.

 This article incorporates public domain material from the United States Government document: "".

External links

• Centers for Disease Control – Chemical Demilitarization
• Chemical Stockpile Emergency Preparedness Program
• Pueblo County Sheriff’s Office CSEPP
• "Department of Public Health and Environment". Cdphe.state.co.us. Retrieved 22 May 2018.
• "United States Department of Defense". Defenselink.mil. Retrieved 22 May 2018.
• U.S. Department of Health and Human Services
• Federal Emergency Management Agency
• U.S. Army Chemical Materials Activity