Worker participation is “essential” to improve process safety and prevent chemical incidents, the U.S. Chemical Safety and Hazard Investigation Board has found. A new document published by CSB identifies four agency investigations in which ineffective worker participation contributed to a major chemical incident. CSB states that a lack of effective worker participation can both increase the risk of injury to employees and adversely affect members of the public who live near industrial facilities where serious safety incidents occur.  The document summarizes key findings from the 1998 Sierra Chemical Company explosives accident, which killed four workers and injured six; the explosion and fire that killed seven employees at the Tesoro Anacortes Refinery in 2010; the 2012 Chevron Richmond Refinery fire that caused 15,000 members of the public to seek medical attention; and the explosion and fire at the Williams Olefins plant in 2013 that killed two workers and injured more than 150 others. The new document is available as a PDF.