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Mission Critical



There’s nothing that puts teeth in a completion deadline quite like an act of Congress. Even if the deadline is 20 years away, when it’s a federal law, blowing it is not an option. That is the background that set up a challenging project undertaken by Industrial Constructors/Managers, Inc. (ICM), an AGC of Colorado Building Chapter member, at the Pueblo Chemical Agent-Destruction Pilot Plant (PCAPP) in Pueblo, Colorado, where they had to build with a proprietary construction system they’d never seen before, on a tight schedule, to facilitate a mission that must not fail.

The three Static Detonation Chambers at Pueblo, Colorado, seen here enclosed in temporary buildings alongside their associated support structures, will destroy the U.S.’s remaining stockpile of mustard agent. PHOTO COURTESY OF ICM


The United States’ chemical weapons stockpile is being destroyed. It has taken decades. The act of Congress that established the current program mandates that all the munitions must be destroyed by Dec. 31, 2023. Accomplishing this task is the job of the U.S. Army Program Executive Office, Assembled Chemical Weapons Alternatives. The “alternatives” program began in the 1990s, identifying environmentally safer methods than incineration, which up until then had been the approved means of chemical weapons disposal (see sidebar, A Brief History of Chemical Weapons Destruction). New methods were identified, such as neutralization followed by biotreatment for destroying the mustard agent-filled munitions.
The alternative destruction program was initiated in 2002. Nineteen years later, the chemical weapons have been eliminated at six out of the original eight storage sites. The remaining two sites have purpose-built facilities that are destroying the last of these dangerous materials: nerve agent in Richmond, Kentucky, and mustard agent in Pueblo, Colo.

The original contract to design, construct, systemize, pilot test, operate and eventually close the Pueblo plant was awarded in September 2002. It began pilot testing in September 2016. The plant had succeeded in destroying the 155mm projectiles (nearly 300,000) by September 2020, and it began destroying 105mm projectiles before the end of that year.

However, some munitions could not be handled by the automated plant, and there is not much time left to complete the program. Those leaky or otherwise problematic munitions have been assigned to a different destruction technology, the Static Detonation Chamber (SDC). Three of these large, specially designed pieces of equipment were commissioned from Dynasafe, a Swedish company that specializes in eco-friendly systems to safely dispose of conventional and chemical munitions. The job of creating the structures to support and house the SDCs was taken on by ICM.

There were three major elements to the project: the foundation, process piping and the “temporary” buildings that enclose the three SDCs.
The SDCs themselves are essentially large tanks where the munitions can be destroyed by heat, with extensive controls and scrubbers to prevent environmentally hazardous products of the destruction from escaping. They are complex, expensive pieces of equipment that stand about 30 feet high on a footprint about 20’ x 20’. Each SDC is enclosed in a tent structure 60’ x 120’ and topping out at 46’ high.


The first challenge was a schedule change: The three SDC structures were supposed to be built sequentially, but because of permitting de-lays, they were rescheduled to construct simultaneously. Fortunately, ICM’s forte is its ability to field its own workforce to quickly respond to tight schedules. “We are carpenters, operators, laborers, millwrights,” explains ICM project manager David Rider. “ICM works on a lot of heavy industrial environments with tight schedules because we have all those trades that directly work for us. Putting them in place simultaneously enables us to stay on time and on budget.”

This situation, however, strained even that large capability. The time crunch forced them to bring in additional talent. The site presented another layer of hiring challenge. Situated on a military base, a remote location in the prairie about 20 miles outside the town, it is a restricted area, and everyone who enters needs a security clearance, limiting who could be hired. ICM worked closely with the unions to find extra workers with special skills and hired 24 extra team members from across the country who joined 66 existing workers for a total of 90 workers at peak construction.

A Brief History of Chemical Weapons Destruction
The United States stopped making chemical weapons in 1968, by which time it had an aging stockpile, much of it dating back to World War II. The Department of Defense (DoD) began to destroy the aging weapons in 1967. The initial program was called Operation CHASE – an acronym for Cut Holes and Sink ‘Em – which dealt with the munitions by packing them into junk ships, and then intentionally sinking them at sea.
In 1970, the environmental movement got a sudden injection of interest and energy with the declaration of the first Earth Day by Senator Gaylord Nelson and Congressman Pete McCloskey. One result was that Congress mandated the Department of Health and Human Services (HHS) and the Office of the Surgeon General (OSG) to review DoD’s plans to transport, test or dispose of lethal chemical agents, and recommend actions to protect the public’s health and safety during such activities. Congress outlawed dumping programs like Operation CHASE with the Marine Protection, Research, and Sanctuaries Act of 1972.
In 1986, Congress mandated the destruction of all US chemical weapons stockpiles. At that point, the only method was incineration. In 1997, we signed the United Nations International Chemical Weapons Convention treaty, committing to a timeline to destroy the weapons by April 29, 2007, a deadline later extended to April 29, 2012. Alternative destruction technologies were investigated in the late 1990s, resulting in the creation of plants that have destroyed the munitions at six of the eight original stockpiles sites.

Because of the environmentally sensitive nature of the materials being handled by the plant, there were very strict controls on any pollution, even from construction activities. “Anytime a piece of equipment would have a leak, you’d shut down and clean the soil,” Rider recalls. It was a project that demanded great attention to detail and extensive documentation of everything that was done.

“One of our taglines has always been that we love a challenge,” says Rick Goodmay, ICM director of client relations, “and this lived right up to it.”
The foundation pour was a particularly complex one. It was a monolithic pour involving continuous curbs around the perimeter and through the middle, four inches deep, to contain any water leakage. The curb was set two feet inside the formwork, and the pour had to be done on three elevations. To facilitate the concrete pour, ICM brought in a power screed and laser leveling. Foundation work took over 5,300 man-hours, with 30 concrete pourers on hand.

Complicating the pour even further, utilities were still being excavated and installed in the ground between the three foundations while the formwork was being built. “Normally you’d have all these utilities installed in the ground first,” Rider says, but because of the schedule ramp-up, ICM had to work around other trades. “We’re were literally installing handrails three feet down the side of the forms so they could dig utilities.”


One key to making the situation viable was daily meetings with all the contractors on-site, working out what each was going to do and what interferences would arise from that. “Communication was paramount,” Rider asserts. “It’s hard to overestimate the problems that were averted because of those daily meetings.”

When the foundation was ready, Dynasafe installed the three SDCs, and ICM moved on to the process piping and racks. There were 12,000 feet of process piping, including copper for water and compressed air, carbon steel for chilled water, and stainless steel for vent gas, which was 100% X-ray to ensure it was leak free and EPA compliant. ICM was able to speed up this phase of the project by fabricating 75% of the piping offsite. They also had to set 50 associated components for each SDC, carbon filtration systems, air compressors and monitoring equipment.

Over all of that, they built the temporary buildings.

“We’d built a lot of buildings,” Rider says, “but the tent was a new challenge.” They are temporary only in the sense that they are intended to be taken down after the mission’s completion in 2023, but they will protect the SDCs for the life of the plant. Made by Sprung Structures, they are comprised of fabric walls erected on massive, extruded aluminum arch frames. Two 60’ x 60’ structures are married together, slightly offset, for each SDC. The arch frames have a channel that allows the exterior membrane and insulation layers to be fed through from one side of the building to the other, utilizing a special winch mechanism.

The manufacturer supplied a rep to assist and, perhaps of even greater impact, a 3D model that could be installed on tablets on-site. “We put four tablets in the field to be able to zoom in and see details,” Rider recalls. Use of the 3D model significantly enhanced their ability to construct the buildings.

From ICM’s point of view, one of the best aspects of the project was how well the team worked together, widely sourced and varied though it was. One member, a cleaner, even received a handwritten letter from the general contractor recognizing his extraordinary work at keeping the site clean and safe.

“It’s important to trust your team and encourage everyone to support each other,” Rider says, “because that produces the best work de-spite pressure from above.”