The Handbook of Hazardous Materials Spills Technology

Part 9: Case Histories

Chapter List

Chapter 40: Long-Range Consequences of a Major Ammonia Accident at Ionava, Lithuania, in 1989
Chapter 41: Historical Analysis of Natural Gas Accidents
Chapter 42: Flixborough The Disaster and its Aftermath
Chapter 43: Chemical Spills At Sea Case Studies
Jaakko Kukkonen, Finnish Meteorological Institute, Air Quality Research
Helsinki, Finland


We evaluated the atmospheric dispersion of ammonia released in a major chemical accident near the town of Ionava in central Lithuania. The course of the accident has been briefly described by Kletz (1991). More detailed reports have been prepared by the Lithuanian State Committee for Environmental Protection (1989) and by Andersson (1991). For a more complete description of this study, the reader is referred to Kukkonen et al. (1993).

The accident occurred at the chemical plant Azot, which produces mainly fertilizers. This plant is situated about 5 km northeast of the town of Ionava. A 10,000-ton-capacity tank containing 7,000 tons of refrigerated ammonia at its boiling point ( ?33 C) split without warning. The rupture was caused by an erroneous filling of the tank with relatively warm (+10 C) liquid ammonia, which formed a layer at the base of the tank. The warm ammonia then suddenly rose to the surface and evaporated, and the pressure rise overwhelmed the relief valves.

The liquid ammonia released formed a pool that was 70 cm deep in places. According to the chemical plant itself, about 1,400 tons of the spilled liquid ammonia evaporated. The pool caught fire, and the fire spread to a...