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This article has been written by Oishika Banerji of Amity Law School, Kolkata. This article provides a detailed analysis of the Trail Smelter case and the legacy it carries on. 


One of the most well-referenced and important decisions in international environmental law began as a local dispute between two small communities and a smelting factory. Northport is a small community in Washington’s Stevens County. The Trail is a community in British Columbia, Canada, about 20 miles north of Northport on the other side of the border. Both cities are located along the Columbia River, which flows from British Columbia to Oregon. A smelting factory in Trail was vital to the economy and way of life of the town’s residents. It had the financial and political clout to get away with contaminating the surroundings and inflicting harm on local farmers’ land. The trash discharged by the factory crossed international borders, resulting in two large-scale international disputes; the first, and most famous, in the mid-twentieth century over air pollution, and the second, in the late twentieth century over slag dumped into the Columbia River. This article provides a detailed analysis of the Trail Smelter case and also presents an insight into the legacy being carried on by the decision made in this case. 

Trail Smelter case

The Trail Smelter case involved the United States suing Canada for infringing on its sovereignty, and the Court’s judgment established basic rules for international environmental law.

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Facts of the case

The Canadian Consolidated Mining and Smelting Company Limited operated a zinc and lead smelter in Trail, British Columbia, about 10 miles north of the international border with the State of Washington. This corporation increased the size of the facility and, as a result, the capacity to smelt zinc and lead ores. Two enormous, 400-foot smokestacks were erected in 1925 and 1927, however. As a result, the amount of sulphur released into the atmosphere increased. The quantity of sulphur emitted from the facility on a monthly basis nearly quadrupled from what it was in 1924 over the same time period. 

Between 1925 and 1935, the United States complained to the Canadian government that the operation’s sulphur dioxide emissions were causing harm to the Columbia River valley in a 30-mile area from the international border to Kettle Falls, Washington. In an attempt to resolve the issue, the two governments used formal arbitration twice, once from 1928 to 1931 and again from 1935 to 1941. The issue was referred to the International Joint Commission by the United States and Canada (IJC-UC) for resolution on August 7, 1928. On February 28, 1931, the IJC-UC determined that the Trail smelter should restrict its sulphur dioxide emissions and that Canada should pay the United States $350,000 in damages. Despite the IJC-UC decision, the Trail smelter’s circumstances did not change. As a result, by February 1933, the US government made further complaints to the Canadian government regarding the smelter’s status. These protests resulted in the two sides signing an emissions Convention on April 15, 1935. The verdict of both the arbitration between the parties (1928-31 and 1935-41) resulted in the Canadian government making a settlement to the State of Washington for the damages it had caused. The latter judgment also established a set of operational standards under which Trail’s smelter would be shut down for at least a year and a half. The United States’ major worry was that the smelter’s sulphur dioxide emissions were affecting the soil and trees of the Columbia River Valley, which were utilized for logging, farming, and cattle grazing, which comprised the most important businesses of that area. Yellow pines, Douglas firs, larch, and cedar were the most impacted species. Alfalfa, wheat, and oat harvests were also affected.

Issues before the Tribunal 

The Convention asked for the establishment of a Tribunal to decide four questions:

1. Has the smelter caused any damage to Washington State since January 1, 1932?

2. Should the smelter be required to refrain from causing damage in the future if it has been shown to have done so?

3. Should the smelting be restricted in any way?

4. In light of the responses to questions 2 and 3, should any compensation be paid?


  1. The Canadian government was ordered to pay the United States $78,000 in compensation for the harm the Trail Smelter caused to the State of Washington between 1932 and 1937. The compensation was mostly for the valley of the Columbia River in the United States.
  2. Instruments to detect wind direction and velocity, turbulence, ambient temperature, barometric pressure, and sulphur dioxide concentrations were to be used at the Trail Smelter. It was also handed a chart listing the maximum acceptable sulphur emissions at each particular time of day. The smelter was required to keep sulphur dioxide emissions below the authorized threshold regardless of weather conditions. Readings from all of the smelter’s instruments were to be sent to the Canadian and US governments on a monthly basis.
  3. The Tribunal concluded that the emissions from Trail caused real damage to the uncleared forest area and cleared farmland along the Columbia River valley in northern Washington State, but not to the land, cattle, or enterprises in over 140,000 acres along the Columbia River valley, as was contended by the US government. In November 1949, the US Secretary of State wrote to the Canadian Ambassador in the US, offering to repay US$8,828.19 that the Canadian government had paid to the US as compensation for losses caused by the Trail smelter’s operation. The refund was accepted by the Canadian government. 

Legal analysis of the case 

In terms of international law, this case was absolutely historic. Never before had the World Court or any other international judicial system pronounced a ruling on a case that was so far away and localized. The Tribunal endeavoured to reach a fair conclusion. The smelter was allowed to resume operations, the farmers were no longer impacted by the smoke and they were compensated appropriately. The overall purpose, as expressed in the decision’s text, was sovereignty. The Tribunal’s ultimate judgment stated that the Dominion of Canada is accountable in international law for the smelter’s acts. 

As long as it follows the law, a State can contaminate its own land as much as it wishes. When pollution crosses an international border and has major consequences, the State has breached international law’s sovereignty premise. The pollution must be of grave importance, implying that the court must determine if the pollution is impeding an individual’s or group’s ability to live a healthy and successful life. In this case, it was never addressed whether or not the smelting smoke was hazardous to the farmers’ health. The Tribunal concentrated on the magnitude of the economic damage caused by the noxious smoke in order to determine whether it was of significant importance. The Tribunal determined that the damage to cleared and uncleared areas was significant enough to justify compensation. It determined that the damage to animals and property in Northport was not severe enough to warrant compensation. What may be learned from this is that demonstrating pollution-caused damage is insufficient. It must be demonstrated that the damage is significant. The meaning of ‘serious’ given by a court is arbitrary and based on the facts and the court.

Principle 22 of the Stockholm Principles lays down that, ‘States shall co-operate to develop further the international law regarding liability and compensation for the victims of pollution and other environmental damage caused by activities within the jurisdiction or control of such States to areas beyond their jurisdiction’. The present case of Trail Smelter is entirely applicable while talking about this Principle. It is important to note that the Court’s judgment was not intended to impose legally enforceable responsibilities on both parties. The choices are a reflection of an aim or a concept of international justice. In light of this instance, two ideas are frequently addressed: 

  1. The first is that a state has a responsibility to avoid transboundary harm.
  2. The polluter pays principle.  

The first solution was to provide direct financial compensation to the farmers. The second solution was to change how activities at the smelter were carried out in order to limit the number of hazardous chemicals generated during processing. For the smelter, this regime was extremely costly, costing roughly $20 million. The Tribunal was essentially putting the smelter on the hook for responsibility and expenses without shutting it down. The State was forced to pay for the terrible damage it had caused to the farmers’ land in order to bring justice to the farmers. As a result, the polluter pays principle was formed. The Tribunal placed a high priority on investigating and determining a regulatory system that would restrict the threat existing to the farmers’ land. Due to the substantial money generated by the Trail smelter, shutting it down would allegedly have negative consequences for Canada’s economy. The Tribunal did not strive to halt pollution as part of what is regarded to be a fair and balanced approach to resolving this problem. Its purpose was to use regulatory approaches to reduce the harm caused by pollution. This may be seen as a flaw in the judgment since it created a precedent of permitting a firm to pollute as long as it paid the price. It may also be claimed that the judgment was acceptable and fair because it protected commercial interests while resolving the situation.


Today, the Trail smelter is still operational. It is owned by Vancouver-based Cominco Limited, which refines lead, zinc, silver, gold, bismuth, cadmium, and indium. The smelter has 125 employees at present. The Trail smelting controversy exemplifies the ongoing fight between big business and the working man, as well as corporate power vs. grassroots activism. Environmental protection is pitted against financial benefits. Perhaps most crucially, it posed a problem to lawmakers in determining how to attain sovereignty between two nations, one of which sought the right to pollute for economic growth and the other protecting its right not to be injured by a foreign country. The two ideas resulting from the first Trail smelter case, namely the polluter pays and that nation’s duty to prevent transboundary harm, are the bedrock of international environmental law.


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