Effectiveness of Improvised Gas Absorption Techniques for Emergency Responders At Releases of Toxic Gases

In September 2011 a spill of nitric acid at a galvanic company in Trieben/Austria caused the release of large amounts of nitrous fumes. An IBC tank with 1000 liter of nitric acid (53%) was flipped over by a forklift and cracked open in the top area. The content was fully released and lead to serious corrosion effects on storage racks combined with the production of critical amounts of nitrous fumes. 27 workers had to undergo medical treatment and a storage and chemical handling area of several hundred square meters was filled by nitrous fumes with concentrations of up to 100ppm.

Emergency responders used an improvised gas absorption system to clear the area of toxic fumes. Outside the sealed area concentrations of nitrous fumes were well below the AEGL-2 (4h) value for nitrous dioxide where measured. In the course of the analyses of the response the effectiveness of improvised gas absorption techniques was investigated.

For the investigations chlorine and ammonia were used in combination with a mobile exhauster, (10.000 m³/h) commonly used by emergency responders. Different methods of gas absorption where investigated and tested upon their practical relevance.