CCAO v0.1: a four-source, deduplicated event-level observatory of chemical accidents in China, 2000-2025, with satellite-based dark-figure benchmarks

CCAO v0.1 (China Chemical Accident Observatory) is the first unified, deduplicated event-level database of chemical accidents in China. It consolidates 2,008 records from four independent documentary systems (Ministry of Emergency Management digests, the French ARIA database's China window, GDELT media events, and the triple-verified literature compilation LAHCA-195) into 1,894 accident clusters spanning 2000-2025. The release includes ccao_v01_events.csv and machine-readable benchmark tables T0-T49 covering capture-recapture dark-figure estimates, breakpoint analysis, inference-protocol verdicts, satellite masking/matching/stratification, population exposure, hotspots, registry cross-check, and imagery-audit products. Companion manuscript: 'A satellite audit reveals that most chemical accidents in China are absent from official records' (Nature Sustainability, submitted).