Consequence assessment on the release of sulphuric acid at Kemira Kemi AB in Helsingborg,2005-02-04

Early in the morning of the fourth of February in 2005, a tank containing sulphuric acid ruptured at Kemira Kemi AB in Helsingborg, Sweden. FOI has on mission for the Swedish Accident Investigation Board investigated the consequences of the event. The course of event started when an underground cooling water pipeline ruptured close to the acid storage. Large amounts of seawater was spread around the tank area. The land was underwashed and eventually the vessel collapsed. Totally 16.300 tons of 96% sulphuric acid was instantaneously released. The contact of acid to the chloride ions in the seawater induced a not foreseen reaction where hydrogen chloride was formed. During the first intensive minutes after the release, some ten tons of hydrogen chloride was dispersed in the surrounding air. A cloud of hydrogen chloride drifted northwards along the coast line and was eventually diluted. After the first intensive minutes the course went into a calmer stage and only smaller amounts of hydrogen chloride was evaporated from the formed pools. The danger of being injured from inhaling the gas was large during the first minutes of the event, within the industrial site. Thereafter the danger zone was narrowed to the area contaminated by the acid-water mixture. Even outside the confined industrial area the risk of moderate to severe irritation in breathing pathways was substantial during the first minutes. Thereafter there was no risk for people outside the industrial area to be affected from the release. The vegetation and animals in the harbour basin was affected by the acidification. The effect was local and temporary. Within a couple of years the environment is expected to be fully recovered.