ATCHISON, KANSAS, U.S. — A chemical incident at MGP Ingredients in Atchison that led to a gaseous plume covering parts of the city on Oct. 21 was the result of two commonly used chemicals — sulfuric acid and sodium hypochlorite (bleach) — being inadvertently mixed during a routine chemical delivery by a MGP supplier, the company said on Oct. 27.

Providing an update on the accident, MGP said the reaction resulted in emissions venting into the air over an area north and west of the Atchison plant. As of 11 a.m. that morning, based on observations by local officials, the emissions had dispersed.

“MGP employees took immediate action, as outlined in our safety protocols, by shutting down plant operations,” the company said. “Our employees also assisted first responders with evacuation procedures in the immediate vicinity of the plant.”

MGP said it reported the chemical release to the Environmental Protection Agency (EPA) and to state and local authorities. The EPA, as well as the Center for Toxicology and Environmental Health, conducted monitoring at the plant and in the community following the incident.

According to MGP, local officials issued an “all clear” for residents and local employees within three hours of the incident occurring.

MGP said approximately 100 people, including 3 of its employees, sought medical treatment related to respiratory concerns as a result of the incident. All individuals who required treatment at local hospitals have been released, the company said.

“MGP has and will continue to closely cooperate to investigate and to fully understand the cause and ensure that all appropriate response actions were taken,” the company said.

The Chemical Safety Board (CSB) is in the process of conducting its own investigation, results of which are expected to be released at a later date per that agency’s schedule and procedural practices. The U.S. Food and Drug Administration (FDA) and the Occupational Safety and Health Administration (OSHA) also have investigated.

Plant operations are fully functional in Atchison, though MGP did indicate that the plant underwent previously planned, regularly-scheduled annual maintenance last week.

“Based on testing and analysis, we are confident our inventories of protein and starch ingredients, as well as distilled spirits, were unaffected and are safe for consumption,” the company said.