The Grandcamp, a World War II Liberty ship that had been converted to a French merchant vessel, was taking on a load of ammonium nitrate fertilizer at a quay next to a complex of Monsanto chemical factories, offices and labs. The ship's carpenter smelled smoke in the No. 4 hold around 8 a.m. on April 16 and found that a few bags of fertilizer were on fire. He tried dousing it with a few buckets of water, then a fire extinguisher.