Seveso made world headlines when, on 10 July 1976, storage vessels at the ICMESA chemical plant ruptured, releasing several kilograms of the dioxin TCDD (2,3,7,8-tetrachlorodibenzo-p-dioxin) into the atmosphere. Tens of thousands of farm animals and pets died or were later deliberately slaughtered, though it is believed that there was not a single human death directly attributable to the incident. The event came later to be known as the Seveso disaster, which later became the eponym for the European Commission's Seveso directive.