What does one do to reduce the potential exposure of workers to low-level hydrogen cyanide when destroying chemical weapons? Turn up the heat.
That's the answer John Barton, chief scientist for Bechtel Parsons Blue Grass, suggested for the pilot plant that will eventually rid Madison County of World War II-era nerve gas and mustard munitions stockpiled at Blue Grass Army Depot. Bechtel Parsons is the contractor for the plant's construction and operations.
Barton spoke Wednesday at a quarterly meeting of groups that discuss the plant's construction progress and other issues surrounding weapons destruction.
Hydrogen cyanide will form as a gas during a step in the plant's neutralization process that will render the rocket warheads and propellents harmless, Barton said. Under the current timeline, the plant isn't scheduled to actually begin destroying weapons until 2020.
Hydrogen cyanide is potentially deadly to humans. It is the active ingredient that the Nazis used to kill Jews in the gas chambers during World War II. It's also present in secondhand cigarette smoke and in certain industrial workplaces. Exposure at lower concentrations can result in nausea, vomiting, headaches, dizziness and other unpleasant symptoms.
Hydrogen cyanide poses no threat to the general public around the depot. Barton and others focused on treating the potential hazard now to protect plant workers in the future.
"If they're breathing this gas in and they experience any health effect, that is not acceptable," Barton said in an interview.
Barton and others confirmed late last year that hydrogen cyanide forms during a step in the neutralization process in which rocket warheads and propellants are "cooked" in a confined space for a number of hours before moving to the next step.
After performing lab and small-scale tests, they settled on this solution: Increase the temperature in a neutralization reactor from 240 degrees Fahrenheit to 300 degrees Fahrenheit.
That change significantly reduces any hazards through contact, inhalation or ingestion. Furthermore, no new chemicals would have to be introduced and it would minimize changes downstream in the neutralization process.
Nevertheless, even with this fix, Bechtel Parsons plans to install air-monitoring equipment to further protect workers, Barton said.
Craig Williams, executive director of the Chemical Weapons Working Group, a Berea-based watchdog organization, said he is satisfied with the measures taken so far to protect workers.
"Their diligence was enough to identify this problem," Williams said. "They've made significant progress in eliminating the problem. We'll be working with them to see what other measures might be necessary to ensure the safety of the workforce associated with this project."
Bechtel Parsons announced this week that the plant's construction is 75 percent complete. However, system installation and the testing of those systems will mean the plant won't begin actual destruction of weapons until 2020. Final destruction of the weapons is scheduled in 2023.
Greg Kocher: (859) 231-3305. Twitter: @HLpublicsafety