The US Department of Defence (DoD), along with Bechtel and its partners, has completed construction of the Blue Grass chemical agent-destruction pilot plant in Richmond, Kentucky, US.
The new plant has been built to safely eliminate the remaining 10% of the nation's decades-old stockpile of chemical weapons.
The Bechtel-led project will undergo a multi-year testing phase to confirm all systems are checked, and simulated chemical weapons are taken apart and emptied.
Bechtel nuclear, security and environmental business unit president Craig Albert said: "This is such an important facility from a global safety and security perspective.
"This is an important achievement but there's more work to do, and we look forward to the day when the plant starts actual operations."
The destruction is being carried out under the Chemical Weapons Convention, a treaty signed by 190 countries in 1997.
The DoD's Program Executive Office, Assembled Chemical Weapons Alternatives, was responsible for the construction of the plant, which will destroy 523t of mustard and nerve agent in rockets and artillery shells stored at the Blue Grass Army Depot.
The plant will use chemicals to neutralise the agents, followed by supercritical water oxidation to break down hazardous chemicals into non-hazardous ingredients.
Responsible for processing weapons containing mustard agent, construction on the explosive destruction technology facility will run until early 2017.
The company is also leading the team that has completed a sister plant in Pueblo, Colorado, to destroy mustard agent. That plant is successfully progressing towards the end of its testing phase.