CSB Probes Fatal Hydrogen Sulfide Release at Maine Pulp Mill

The U.S. Chemical Safety and Hazard Investigation Board (CSB) said it has opened an investigation into a fatal chemical release at the Woodland Pulp facility in Baileyville, Maine, that occurred Jan. 27, 2026.

According to the agency, the incident resulted in one fatality involving a 20-year-old college intern and injured nine other workers, two seriously, with one still hospitalized. Initial information submitted to the CSB indicated the event may have involved the mixing of concentrated sulfuric acid with sulfurous compounds in an enclosed process sewer, generating hydrogen sulfide gas in the bleach plant area.

The CSB said its investigation will examine the circumstances surrounding the release, including chemical handling practices, process safety systems and emergency response actions. Investigators have been deployed to the site and will gather evidence, conduct interviews and review relevant documents.

CSB Chairperson Steve Owens said the agency’s investigation will seek to determine the cause of the incident and identify steps to prevent similar events.

In other recent activity, the CSB released a safety video on the fatal 2017 combustible dust explosions at the Didion Milling facility in Wisconsin, where five employees were killed and 14 injured. The agency again called on the Occupational Safety and Health Administration to develop a comprehensive combustible dust standard for general industry.

The CSB also reported that St. Louis updated its Mechanical Code to strengthen in-service inspections of boilers and pressure vessels, following recommendations issued after the 2017 explosion at the Loy-Lange Box Company that killed four people. According to the agency, the revisions adopt national inspection standards and establish minimum qualifications for inspectors.