BAILEYVILLE, Maine — Federal investigators are looking into a chemical release at the Woodland Pulp mill in Baileyville that killed one worker and injured nine others. The US Chemical Safety and Hazard Investigation Board said Monday it has opened an investigation into the January 27 incident at the facility. One of the injured workers remains hospitalized. The person who died was a 20-year-old University of Maine student taking part in an internship at the mill. According to the company, the release may have occurred when concentrated sulfuric acid mixed with sulfurous compounds within an enclosed sewer. The reaction can generate toxic hydrogen sulfide gas. The release occurred in the mill’s bleach plant area. Investigators will examine chemical handling practices, process safety systems, and the company’s emergency response. A team has already been sent to the site to collect evidence, conduct interviews, and review records.