For days, a foul smell hangs around in the Humberto Vidal shoe store in San Juan, Puerto Rico. The smell is caused by leaking propane gas coming from an unmapped pipe in the sloping road near the shoe store. The gas goes undetected due to faulty gas searching techniques. Then, an air conditioner with bad wiring is switched on, starting a spark that ignites the propane and the store explodes, claiming 33 lives.
