A unconnected tanker truck carrying liquid ammonia (NH3) burst open at an industrial facility. Propelled by chemical reaction, with the front part “of the tanker clipped some of the installations then smashed into the wall of an electrical service building, while the back part angled at 45° upward violently smashed against the reinforced concrete lintel of a neighbouring building, then ricocheted in the direction of the unit, seriously damaging its upper level. An axle was found 200 m away on a nearby site. A portion of the 22 tons of NH3 contained in the tank spread through the installation, while another portion was projected with the back of the tank beyond the site boundary. According to eyewitness accounts, the whitish toxic cloud moved about 250 m and dissipated within 10 to 15 min. Liquid NH3 projection lengths reached some 30 meters. The noxious atmosphere hindered the emergency intervention team, which was not equipped with adequate protection, including masks and oxygen cylinders. Both the time (1:30 pm, as a new shift was taking over) and the place of the accident, near the port’s industrial rehabilitation zone, would explain in part the tremendous number of casualties: 129 dead and 1,150 injured, with some victims being burned directly by NH3 or intoxicated by NH3 vapours. Other victims with outbreaks of lesions were diagnosed as not serious at first, but went on to develop a fatal pulmonary oedema just a few days later. According to the press, onlookers heard the sound of the explosion and flocked towards the contaminated zone, only to fall victim to the accident as well.
This accident was due to overfilling of the tank (22.2 tons for a 17.7-ton capacity), which seems to reflect frequent practice. The tank broke at the level of a repair weld performed 2 years prior upon detection of a leak during a hydraulic test.