Swiss Warehouse Fire Causes Toxic Spill into the Rhine

Firefighting in a chemical storage warehouse resulted in a spill of large quantities of toxic materials into the Rhine River, causing massive loss of river life.

Summary of Event

Early in the morning of November 1, 1986, a fire was reported in a chemical storage warehouse located in Schweizerhalle, Switzerland, a suburb of Basel. Drums filled with various chemical substances stored in the warehouse ruptured and spilled their contents during the blaze. Water that was sprayed onto the fire carried these chemicals into catch basins that soon overflowed, carrying tons of hazardous materials, primarily agricultural chemicals along with a significant quantity of mercury-containing compounds, into the nearby Rhine River. The spill resulted in a massive kill of aquatic life, with the most profound effects noted over a stretch of two hundred miles from the original spill. Disasters;industrial
Ecological disasters
[kw]Swiss Warehouse Fire Causes Toxic Spill into the Rhine (Nov. 1, 1986)
[kw]Warehouse Fire Causes Toxic Spill into the Rhine, Swiss (Nov. 1, 1986)
[kw]Fire Causes Toxic Spill into the Rhine, Swiss Warehouse (Nov. 1, 1986)
[kw]Toxic Spill into the Rhine, Swiss Warehouse Fire Causes (Nov. 1, 1986)
[kw]Spill into the Rhine, Swiss Warehouse Fire Causes Toxic (Nov. 1, 1986)
[kw]Rhine, Swiss Warehouse Fire Causes Toxic Spill into the (Nov. 1, 1986)
Rhine River;toxic spill
Ecological disasters
[g]Europe;Nov. 1, 1986: Swiss Warehouse Fire Causes Toxic Spill into the Rhine[06200]
[g]Switzerland;Nov. 1, 1986: Swiss Warehouse Fire Causes Toxic Spill into the Rhine[06200]
[c]Disasters;Nov. 1, 1986: Swiss Warehouse Fire Causes Toxic Spill into the Rhine[06200]
[c]Environmental issues;Nov. 1, 1986: Swiss Warehouse Fire Causes Toxic Spill into the Rhine[06200]
[c]Animals and endangered species;Nov. 1, 1986: Swiss Warehouse Fire Causes Toxic Spill into the Rhine[06200]
Winkler, Hans
Moret, Marc
Egli, Alphons

The warehouse involved in the incident had originally been built for machinery storage in 1968. In 1978, the building was approved for the storage of chemicals by the appropriate Swiss government agencies; the Sandoz Company Sandoz Company subsequently used it for storage of chemical products. The government guidelines at this time, however, were not particularly stringent for storage facilities of this type. Automatic sprinkler systems linked to heat detectors were not required by law, nor were adequate water drainage and containment facilities available to handle the large runoff generated from fighting such a fire. The latter, in particular, would have greatly diminished the impact of this incident, as adequate drainage and containment facilities would have prevented the flow of contaminated water into the river. It was not so much the building itself as the government regulations that were not sufficient to prevent the disaster.

Investigators linked the source of the fire to a shrink-wrapping process taking place in the building. The fire spread very rapidly and was fought by both local firefighters and contingents from neighboring chemical firms, including Ciba-Geigy. Ultimately, nearly two hundred firefighters were involved in combating the blaze, which took approximately five hours to bring under control.

At the time of the fire, the warehouse held approximately fourteen hundred tons of chemical substances, including several pesticides Pesticides such as parathion, atrizen, and disulfeton, a particularly toxic pesticide that was detected as far as 350 miles downstream after the spill. In addition, a mercury-containing fungicide called Tillex was present in substantial quantities.

Drums containing these and many other materials were ruptured by the heat of the fire, and their contents were spilled. The firefighters did not utilize foam agents to smother the blaze; rather, they sprayed large volumes of water onto it. The resulting runoff overwhelmed the drainage and containment facilities of the warehouse. This water surged directly into the Rhine, carrying a mixture of chemical substances along with it. Dyes that were mixed in with the other materials gave the resulting slick a red appearance. Indeed, the color led to early announcements that the spill involved nothing more than a dyestuff that was producing a temporary discoloration of the water.

In addition to initiating the flood of chemicals washed into the river, the fire generated a large vapor cloud that contained a mixture of nitrogen oxides. As the cloud spread over the area, its appearance prompted local police to warn residents to stay in their homes with their windows closed. Many of the area residents were guest workers who did not speak German, however; they could not understand the warning, and many opened their windows so they could look out and see what was happening. As a result, several city residents were hospitalized for respiratory problems resulting from fume inhalation.

It was soon readily apparent that the spill was not merely a dye, because shortly after the runoff entered the river, large numbers of dead fish washed up onto the shore. A more disturbing sight was the number of dead eels, which are normally more resistant than fish to chemical spills. The eel deaths were an indicator that some of the materials, most likely the mercury-containing ones, had sunk to the bottom of the river and probably remained there. By mid-December, it was reported that the river was essentially devoid of fish. In addition, it appeared that the microscopic organisms at the base of the food chain were dramatically affected, although the high flow rate of the river would help in the reestablishment of the river’s ecosystem.

Analysis was begun on water samples to determine what materials were released. Curiously, investigators found evidence of significant quantities of a pesticide that was not on the list of chemicals in the warehouse inventory. This mystery was solved when neighboring manufacturer Ciba-Geigy Ciba-Geigy[Ciba Geigy] admitted that the night before the Sandoz fire, workers had accidentally released a pesticide into the Rhine. About one week after the fire, a containment dike at the Sandoz warehouse site was breached, releasing yet another batch of toxic materials into the river.

This incident received far more press coverage than did the massive fish kill that occurred in the Rhine during 1969. Public reaction was immediate and very bitter, both in Switzerland and in the other nations along the Rhine. On the day after the fire, Hans Winkler, who was then safety director for Sandoz, and other officials of the company and the government held a press conference at which they were hit with dead eels and spat upon by protesters. A massive march was held in Basel to protest the spill, and other protests were held throughout Europe, one of the better-publicized events being a “requiem” for the Rhine. Fuel was added to the outrage by reports of other releases into the Rhine over the next few weeks, although these releases were, for the most part, within legal limits. Comparisons of the fire to both the Bhopal, India, chemical discharge disaster and the Chernobyl nuclear plant accident were made both by protesters and by government officials.

The chairman of Sandoz, Marc Moret, publicly apologized for the fire and its effects and stated that the company would assume responsibility for damage payments and would establish a fund to investigate the aftereffects of the spill. Initial estimates placed the projected damages from the spill at more than $100 million. Alphons Egli, the presiding member of the Swiss Federal Council at the time of the incident, acknowledged in an address to the Federal Assembly, Switzerland’s parliament, that tremendous damage had been done to Switzerland’s national image as a result of the spill.


In the immediate wake of the fire and spill, there was consensus that ongoing efforts to clean up the Rhine had suffered a severe setback. Pollution of the river had reached such high levels in the late 1960’s and early 1970’s that the river was frequently referred to as the sewer of Europe. Treaties and legislation signed in 1976 as well as citizen pressure on governments and industry had led to significant progress in cleaning up the river. Not surprisingly, many gloomy predictions were made about the long-term impact of the spill on the river. Within a few months, it was apparent that the major damage done was to the bottom-feeding population of the Rhine. This assessment resulted in a program of dredging to remove the contaminated layer of silt from the river bottom, and it was expected that the river would show signs of recovery the following spring. Rhine River;toxic spill

Indeed, within a year the river had shown substantial signs of recovery, with change occurring more rapidly than even the most optimistic observers had predicted. The Rhine was a heavily polluted river, however, and even recovery to a state similar to that preceding the fire left a river that was still far from pristine. Nevertheless, the spill did inject new vigor into long-term programs for rejuvenation of the Rhine. By the early 1990’s, these plans had begun to incorporate components dealing not only with pollutant discharge and regulation but also, more fundamentally, with regulation of the river channel itself, the goal being to return the Rhine to a more natural state. This included such projects as wetlands rejuvenation and re-creation of natural floodplains, programs that would enhance the ability of the river to cleanse itself.

The spill also caused significant changes in legislation and policies among the European countries bordering the Rhine. A 1976 treaty, the Rhine Chemical Convention, Rhine Chemical Convention (1976) contained specific provisions about safe storage measures and international warnings of impending hazards. There was no real way to enforce the provisions of the treaty; it was essentially useless at the time of the Sandoz fire. Because the Swiss government quickly accepted responsibility for the spill and agreed to pay for damages, no significant action was taken under international law. In the years after the fire, however, the Swiss government did have to settle more than nine hundred claims made by a variety of organizations and governments. In addition, the company followed up on its pledge to establish a research fund to investigate the aftereffects of the spill.

In the months following the spill, Sandoz and many other chemical companies in the region took significant steps to lessen the possibility of another such event. Because spills most often occur during the manufacturing and transportation processes, many manufacturers consider the safety of their storage facilities belatedly. Sandoz in particular introduced fundamental changes into its operation, including the elimination of all mercury-compound production. In addition, production of many materials was slowed to lower the amount of materials requiring storage.

Steps taken by other companies included simple scaling down of hazardous-material production and, more fundamentally, modifications of manufacturing procedures to reduce the need for storage and transportation of chemical intermediates—that is, substances that are typically generated in the manufacturing process for use in a later step of the process. Intermediates are often hazardous and reactive. Companies such as Ciba-Geigy announced that they would modify particular procedures so that certain hazardous intermediates would be generated on-site and used as soon as possible rather than transported and stored.

Coupled with these changes were efforts to improve the public images of the companies and to restore lost confidence. Companies such as Sandoz and neighboring Ciba-Geigy took press groups on tours of their facilities to demonstrate the improvements that had been made and the conditions under which operations were carried out. Such encounters typically had the desired effect, primarily because of their educational content.

Perhaps the most interesting subsequent development in the case is the research fund that Sandoz established for study of the spill’s aftereffects. The fund of almost $7 million supported thirty-six projects that led to a much greater understanding of the impact of pollutants on the Rhine. One such project found that the large particulate content in the Rhine lowers the impact of pollutants. It was also discovered that blockage of tributaries is an impediment to recovery after contamination and has a greater long-term effect than the contamination itself. Rhine River;toxic spill
Ecological disasters

Further Reading

  • Klaffke, Oliver, and Alison Abbot. “Sandoz-Funded Research from Rhine Spill Suggests Blockages Are Worse than Toxins.” Nature 359 (October 15, 1992): 568. Provides an excellent brief overview of the independent projects funded by Sandoz to investigate aftereffects of the spill.
  • Layman, Patricia E. “Rhine Recovers from Last Year’s Sandoz Chemical Spill.” Chemical and Engineering News, November 9, 1987, 16-17. Presents a brief summary of developments within one year of the incident. Includes a description of steps taken by Sandoz to curtail large-scale production of hazardous substances.
  • _______. “Rhine Spills Force Rethinking of Potential for Chemical Pollution.” Chemical and Engineering News, February 28, 1987, 7-11. Well-written article outlines the actions taken by European chemical manufacturers immediately after the spill. Summarizes legislation concerned with Rhine pollution.
  • Pearce, Fred. “Greenprint for Rescuing the Rhine.” New Scientist 138 (June 26, 1993): 25-29. Excellent article outlines the history of the Rhine in terms of channel control and industrial development. Focuses on the growing awareness that environmental restoration may be a more effective means of restoring the Rhine than merely relying on pollution reduction.
  • Schwabach, Aaron. “Death Watch on the Rhine.” Business and Society Review 75 (Fall, 1990): 36-40. Written four years after the Basel incident, this work gives a brief overview of the event and an excellent description of its aftermath. Includes a summary of pertinent legislation and an overview of legal settlements.

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