Safe, environmentally sound destruction of chemical weapons

Though never used by the United States, chemical weapons were stockpiled by the U.S. Army at a number of bases during and after World War II. In 1985, Congress decided to turn the aging weapons into a harmless part of history. Today, a Bechtel-led team is destroying chemical weapons under contract to the Program Executive Office - Assembled Chemical Weapons Alternatives and supporting national commitments under the Chemical Weapons Convention.

The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) is a state-of-the-art facility built to safely and efficiently destroy the chemical weapons stockpile currently in storage at the U.S. Army Pueblo Chemical Depot near Pueblo, Colorado.

The Bechtel Pueblo Team, which includes Bechtel, URS, Battelle Memorial Institute, and Parsons Infrastructure and Technology, won the competition in 2002 to design, build, test, operate, and ultimately close PCAPP after destroying the stockpile. 

More than 2,600 tons of mustard agent in artillery projectiles and mortar rounds stored here. After the chemical weapons have been eliminated, the plant will be closed in an environmentally responsible manner. Unlike other demilitarization facilities, this one dismantles munitions using a first-of-a-kind robotic process.

Bechtel also built and is operating the Blue Grass Chemical Agent-Destruction Pilot Plant in Richmond, Kentucky.

Image gallery

Over 2,600 tons of mustard agent in artillery projectiles and mortar rounds stored at Pueblo will be destroyed
Unlike other demilitarization facilities, Pueblo dismantles munitions using a first-of-a-kind robotic process
The Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) was built to safely destroy the weapons stockpile at the US Army’s Chemical Depot
After the weapons have been eliminated, the plant will be closed in an environmentally responsible manner
Engineers review progress at the plant
Engineers inspect the plant
Bechtel’s team has earned numerous honors, including exceptional achievement or Star level, in OSHA’s Voluntary Protection Program
Management reviews the mortar disassembly machine
A view of the concentrator feed tank
Project members inside the plant
The beginning construction of the Sprung structures
PCAPP crews work to begin the placement of the Sprung structures
Progress of the Sprung structures with the tension fabric to cover the three chambers
Local utility electrical power is connected to the Static Detonation Chamber site
The pilot plant began initial operations in September 2016, destroying its first-ever chemical weapons
The plant utilizes a safe technology—neutralization followed by bio treatment—to destroy weapons stored at the Pueblo Chemical Depot
Aerial view of the Static Detonation Chambers.

Achievements to date

As of early 2022, the Pueblo Chemical-Agent Destruction Pilot Plant had destroyed more than 80% of the stored mustard agent awaiting destruction. That equates to more than 2,100 tons of agent that has been destroyed and eliminated from the U.S. Army stockpile.

The Bechtel Pueblo Team has earned a number of honors, including exceptional achievement, or Star level, in the U.S. Occupational Safety and Health Administration’s Voluntary Protection Program. This program recognizes U.S. worksites that have exemplary records and demonstrate commitment to workplace safety and health.

Initial operations achieved in 2016

PCAPP began initial operations in September of 2016, destroying its first-ever chemical weapons. The milestone brought the U.S. one step closer to meeting treaty obligations to destroy its remaining chemical weapons stockpile. The construction phase of the Pueblo Chemical Agent-Destruction Pilot Plant was completed in 2013. During construction, craft workers hired from the Colorado Building & Construction Trades Council, installed more than $200 million worth of underground utilities, redundant electrical and control systems, titanium piping and storage systems, and specialized first-of-a-kind equipment.

PCAPP completed its systemization phase in 2016, a period during which more than 300 associated subsystems, spread over an 85-acre site, were tested to make sure they work and function together properly.

Static Detonation Chambers

Three new Static Detonation Chambers will be used to destroy  4.2-inch mortar rounds and any projectiles not suitable for the automated processing in the main plant. These chambers safely destroy chemical munitions, energetics, and associated waste items using indirect heat.      

Learn more

Visit the Pueblo Chemical Agent-Destruction Pilot Plant website.

How it works

The Department of Defense’s Assembled Chemical Weapons Alternatives program worked together with the community to select a safe technology—neutralization followed by bio treatment—to destroy the chemical weapons stored at the Pueblo Chemical Depot. The five steps:

  1. Robotic equipment removes explosives from the weapon.
  2. The system remotely accesses the weapon’s interior and washes out the mustard agent with water under high pressure.
  3. Next the facility neutralizes mustard agent with caustic solution and hot water. The byproduct is hydrolysate.
  4. Microbes treat the hydrolysate, breaking it down into brine. The brine is separated and the water recycled. Staff ship the resulting salt cakes for disposal at a permitted facility.
  5. After heating metal parts to 1,000 degrees Fahrenheit (nearly 538 degrees Celsius) for 15 minutes, crews send them out for recycling.