This bill amends the Clean Air Act to modify the requirements for members of the Chemical Safety and Hazard Investigation Board, which investigates chemical accidents and safety incidents. The legislation requires that at least one of the board's five members must have demonstrated knowledge and substantial experience in trades or industrial labor, ensuring that workers' perspectives are represented in safety investigations. The bill also establishes specific procedures for filling board vacancies, requiring the President to either nominate a replacement within 90 days or submit a report explaining the delay and outlining a timeline for nomination, with ongoing reporting required every 90 days if the vacancy remains unfilled. Members would continue to serve five-year terms and be selected based on technical qualifications and professional expertise in relevant fields such as accident reconstruction, safety engineering, and toxicology. This measure aims to enhance accountability and worker representation on the board that oversees chemical facility safety.