In 1986, Schweizerhalle was considered one of the most dangerous places in the world due to a major fire at a chemical plant. "Today, it's one of the safest places in Switzerland," says Christian Pauli, Managing Director of the Swiss Association for Temperature-Controlled Logistics (SVTL). Certainly the right place for an event focusing on the Major Accident Hazard Ordinance and occupational safety.
Last year saw several incidents involving ammonia at major facilities in Zurich and Gossau. This prompted around 30 interested participants to seek information from experienced experts about precautions and measures to be taken in the event of such an incident.
Emergency response. Photo: Zurich Police Department
At the end of May, a large quantity of ammonia leaked from a heating plant (Hardau II, Zurich). Because the Major Accident Ordinance applies in such cases, over 100 firefighters were immediately deployed. At the end of August, large quantities of the toxic refrigerant leaked from a Migros food processing plant in Gossau. As a precaution, 70 employees were evacuated, and ten had to be hospitalized. Here, too, around 100 emergency personnel from the fire department, hazardous materials unit, ambulance service, and police were involved. In November, ammonia leaked from the cooling system of a vegetable processing factory in Dällikon, and 180 people were temporarily evacuated. In addition to 40 members of the Zurich Cantonal Police, 23 ambulances from Zurich's Protection & Rescue service, the Limmattal, Bülach, Horgen, Einsiedeln, Lachen, and Aarau hospitals, the Schwyz ambulance service, the Zurich Forensic Institute, and the responsible public prosecutor rushed to the scene.
L. Vonbach, P. Gschwind
Ammonia is the most widely used refrigerant in Switzerland. An estimated 90 to 95% of all industrially used systems with a capacity of 400 kW or more are operated with it. Even in larger ice sports centers, such as the one in Zuchwil near St. Gallen, 5,000 kg of the refrigerant can quickly be involved. Caution is always advisable. Although, as one expert explains, it would almost take a plane crash or the roof of the ice rink collapsing and tearing open the floor to have to expect the worst. Nevertheless, there are 15 artificial ice rinks in the canton of Zurich alone (around 110 throughout Switzerland) that use ammonia as a refrigerant. The stored quantities typically range between 3,000 and 11,000 kg. And from 2,000 kg upwards – which applies to a total of around 150 refrigeration systems in Switzerland, primarily larger ones – the Major Accident Hazard Ordinance comes into effect. Heat pumps can also be affected.
M. Christiansen
Occupational safety and health consultant Alex Mühlemann warned those present from the refrigeration industry against taking negligence and precautionary measures lightly, such as "We've always done it this way" or "Nothing's ever happened before." This starts with safety shoes and the role model function at the management level. SVTL President Marco Manzetti emphasized the importance of a strong safety culture. "Once the public prosecutor's office is at your door and you're practically facing jail time, the fun stops." The boss must be able to prove that they have taken all the required measures. "But it's not just the employer who is responsible," said Mühlemann, "employees must also follow all safety regulations." Insurance companies react sensitively to incidents by increasing premiums, and a company's image can also suffer quickly.
Hazardous areas. Photo: BAFU
Michael Christiansen, from the energy and industrial services provider Getec, located just 800 meters away in Schweizerhalle ("I have the scene of the 1986 fire in front of me every day at my desk"), explains details of the Major Accident Ordinance (StFV), which came into force in 1991. For those unfamiliar with it, this ordinance contains some rather peculiar categories. For example, the StFV primarily serves civil protection – and initially doesn't address the employees of the company in question (who fall under occupational safety regulations). "What do you do if you also have a daycare center or a canteen on the premises that is open to the public?" he asks. In such cases, liability needs to be clarified.
A. Mühlemann
Cold bureaucracy prevails when it comes to the question: "Who is considered dead?" Anyone requiring hospital treatment for more than three hours is initially no longer counted among the survivors in the summary report, according to the Major Accident Ordinance. Extensive tables, calculations, and impact models outline the risks associated with the spread of a toxic cloud based on average wind directions and speeds; fewer than ten potential fatalities are considered a lower risk level in the assessment of the likely hazard in a real-life scenario. More detailed questions from the participants underscored the importance of a heightened safety culture.
Accident expert Lukas Vonbach, who points out that there are certainly other dangerous substances, also likes to quote Friedrich Dürrenmatt's "The Physicists": "The more systematically man proceeds, the more effectively chance strikes him..."
In the premises of the Muttenz Water Sports Club, thirst was quenched along with food and drink – under a low risk level.
K. Koch
The Major Accident Ordinance for refrigeration systems is available for download
