Every U.S. Chemical Safety Board (CSB) investigation — 139 independent root-cause investigations of the most serious chemical incidents (1998-2026): explosions, toxic releases, and fires including BP Texas City, West Fertilizer, DuPont, Bhopal-class disasters. 131 completed + 8 active. Per investigation: title, company, location + state, status, final-report date, summary, and a link to the CSB report page. The deep-investigation layer over the EPA RMP accident ledger (RMP = every reportable accident; CSB = the in-depth probes of the worst). Institution/incident-level only — the report-page URL is stored, never PDF bodies (which can name victims). Powers /chemical-investigation/{tid} canonical pages + /api/v1/csb/{search,list}. Joins EPA RMP + entity layer by company/state.
Every record in this dataset can be traced back to its primary source at https://www.csb.gov/investigations/. Underlying content is a US federal government work (public domain under 17 USC §105); our derived data is licensed CC0 1.0.