This report synthesizes key lessons from major industrial accidents in the chemical, petrochemical, oil & gas, pharmaceutical, and manufacturing sectors worldwide. We review 10–15 high-impact incidents (1970s–2020s), analyzing their root causes, technical failures, human and organizational factors, and the regulatory and standards reforms that followed. Incidents covered include Flixborough (1974), Seveso (1976), Bhopal (1984), San Juanico (1984), Piper Alpha (1988), Phillips Pasadena (1989), Skikda (2004), BP Texas City (2005), Buncefield (2005), West Pharmaceutical (2003), Imperial Sugar (2008), Deepwater Horizon (2010), West Fertilizer (2013), and Tianjin (2015).