Chlorine gas released in Kansas distillery chemical mix-up

An accident at a distillery in Atchison, Kan., that released a cloud of chlorine gas was apparently caused by a chemical safety textbook example of what not to do: mixing sulfuric acid with sodium hypochlorite.

The U.S. Chemical Safety & Hazard Investigation Board is probing the incident and is expected to make a final determination of the cause.

The accident occurred on Oct. 21 at MGP, which describes itself as a leading supplier of premium distilled spirits and specialty wheat proteins and starches. It produces alcohol used for vodkas, gins, bourbons, and whiskeys. The company employs approximately 270 people.

A supplier was delivering sulfuric acid to the facility, explains Trey Cocking, Atchison city manager, “and instead of putting the acid into the sulfuric acid tank, it went into the sodium hypochlorite tank. That led to a reaction.” When sodium hypochlorite is mixed with acid, chlorine gas is produced.

Residents near the distillery began to smell a strong odor of chlorine and a thick fog emanated from the plant, sweeping over the town of 11,000, according to news accounts. Those living north of the plant in the area of the plume were told to shelter in place. At one point, authorities considered evacuating the entire city. More than 135 people complained of burning lungs and difficulty in breathing and were treated at area hospitals, Cocking says. Only one person was admitted and has been released, he adds.

Three company employees plus the truck driver delivering the acid required medical attention. In addition, 27 city employees have sought medical attention, including police, fire, and public works city staff.

“We are a small community with only five firefighters, and maybe 15 emergency responders came in from nearby jurisdictions,” Cocking says. “We went through hazmat procedures and put water in the tank, and the reaction slowed and stopped.”

The plant is now shut down. MPG would not comment on the incident.