The U.S. Chemical Safety and Hazard Investigation Board (CSB) says Yenkin-Majestic/OPC Polymers has not responded substantively to five safety recommendations issued after a fatal 2021 explosion and fire at the company's resin manufacturing facility in Columbus, Ohio.

The CSB issued the recommendations in November 2023 following its investigation into the April 2021 incident. The agency says the company has not responded despite repeated attempts to secure action on the recommendations.

One employee died from burns and smoke inhalation. Eight others were hospitalized with injuries, including third-degree burns and fractures. One employee required a leg amputation after being trapped beneath collapsed debris.

Investigators determined that an improperly designed, constructed or tested reactor manway cover contributed to the explosion. The company also failed to follow basic quality assurance practices for pressure vessel integrity.

A mixture of flammable naphtha solvent vapors and resin liquid became pressurized and escaped through the manway seal. The resulting vapor cloud ignited, causing the explosion and fire.

The CSB also identified deficiencies in emergency preparedness and training. The facility lacked adequate audible and visual evacuation alarms, and the company did not require employees to wear flame-resistant uniforms.

The agency first sent its recommendations to the company in a December 4, 2023, letter addressed to then-President and Chief Executive Officer Andrew O. Smith. After repeated attempts to obtain a response, the CSB sent another letter to Smith on February 5, 2026. Smith had become executive chairman of OPC Polymers LLC in early 2023.

The company did not respond to either effort, according to the CSB. On September 1, 2026, Yenkin-Majestic pleaded guilty to federal criminal charges related to the 2021 incident. Nine days later, CSB Executive Director of Investigations and Recommendations Stephen Klejst sent another letter urging the company to engage with the agency and implement the recommendations. The company again did not respond.