What happened

A major overnight fire swept finished-product storage at Lubrizol's Seveso upper-tier chemical site and three neighbouring NL Logistique warehouses holding chemicals, including Lubrizol products. French public-health and government records describe Lubrizol as a manufacturer of additives for industrial and motor lubricants; the available official material does not justify simplifying the site to a gasoline- or diesel-additive plant. More than 5,000 tonnes of chemical products were involved, a large black plume and soot deposits crossed a wide area, agricultural precautions were imposed and environmental and health monitoring followed. Authorities brought the main fire under control on 26 September, although damaged drums continued smouldering at NL Logistique until 7 October. An emergency prefectural order suspended site operations and required polluted firewater and waste to be secured and removed. No death or acute on-site injury was reported in the cited official summaries; reports of symptoms and healthcare use in the surrounding population are not converted here into a single casualty number.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.