Pesticides Are Released into the Sacramento River Summary

  • Last updated on November 10, 2022

When a railroad accident six miles north of Dunsmuir, California, spilled thirteen thousand gallons of the pesticide metam sodium into the Sacramento River, aquatic life was destroyed in more than forty miles of the river.

Summary of Event

On July 14, 1991, a railroad car containing 19,500 gallons of the pesticide metam sodium derailed, and the pesticide leaked into the upper Sacramento River six miles north of Dunsmuir, California. The pesticide killed all aquatic life in the river for a distance of forty-five miles downstream to Lake Shasta, a huge impoundment that supplied irrigation and drinking water to most of Northern California. Disasters;chemical contamination Sacramento River pesticide spill Pesticides Ecological disasters [kw]Pesticides Are Released into the Sacramento River (July 14, 1991) [kw]Sacramento River, Pesticides Are Released into the (July 14, 1991) [kw]River, Pesticides Are Released into the Sacramento (July 14, 1991) Disasters;chemical contamination Sacramento River pesticide spill Pesticides Ecological disasters [g]North America;July 14, 1991: Pesticides Are Released into the Sacramento River[08150] [g]United States;July 14, 1991: Pesticides Are Released into the Sacramento River[08150] [c]Disasters;July 14, 1991: Pesticides Are Released into the Sacramento River[08150] [c]Environmental issues;July 14, 1991: Pesticides Are Released into the Sacramento River[08150] [c]Animals and endangered species;July 14, 1991: Pesticides Are Released into the Sacramento River[08150] Mohan, D. Mike Reilly, William May, Dick Cronin, Leo

The accident occurred on the main rail line of the Southern Pacific Railroad at a curve known as Cantara Loop, where the railroad crosses the Sacramento River. The train was made up of ninety-seven cars with a combined weight of 4,290 tons and four locomotives pulling the train from the front. Trains weighing more than 4,500 tons require the use of a pusher locomotive at the rear, to maintain traction when ascending mountain bases as well as to relieve the lateral strain around the 180-degree curve of Cantara Loop. On the night of the accident, the locomotives lost traction rounding Cantara Loop, then regained traction and yanked the train forward. A locomotive and seven cars were pulled off the rails. The tank car carrying the metam sodium fell from the curved bridge into the Sacramento River. A hole was torn in the car’s single-walled tank, and most of the contents leaked into the river.

Railroad crews following standard procedure immediately rushed in and pumped the diesel fuel that had begun to leak from the derailed locomotive but did nothing about the pesticide leaking from the ruptured tank car. The Environmental Protection Agency Environmental Protection Agency (EPA) and the U.S. Department of Transportation do not consider metam sodium Metam sodium a hazardous material; therefore, the train manifests listed the contents of the tank car simply as a weed killer, with no special precautions noted for handling the contents in case of accident or spillage.

Metam sodium is a popular pesticide in part because it effectively kills a wide range of both plant and animal life. It is used as a soil fumigant. When mixed into soil, it reacts with water in the soil to produce two deadly chemicals, methyl isothiocyanate and hydrogen sulfide gas.

When the metam sodium leaked into the river, the river flow carried it downstream more than forty miles, until the mass of pesticide reached Lake Shasta, the huge impoundment that supplies water to much of Northern California. On its trip down the river to Lake Shasta, the pesticide killed every organism in the river, from ducks and trout (which supplied the region with its economic base as a sportfishing destination) through the insects and smaller fish that make up the trouts’ diet, down to the algae. Several days after the spill, even the trees along the riverbank began to die. The death of the river also affected the myriad animals—including beavers, eagles, bears, and otters—that depended on the river as a major food source.

In addition to the devastating effects on the environment, the spill also affected the residents and the economy of the area. Sixty miles of Interstate Highway 5, the main road that shares the valley with the Sacramento River and the railroad line, were closed. Hundreds of residents were evacuated from the area. Boating and fishing were banned at the northern end of Lake Shasta, where the flow of poisoned water entered the lake. The area’s economy is based on recreation, sportfishing in particular, so the death of the river was expected to have long-term economic impacts.

Thirteen thousand gallons of the poisonous metam sodium eventually leaked from the tank car and made its way into the northern end of Lake Shasta, where it floated as a huge green mass near the surface of the lake. To clean up the lake, authorities implemented a newly developed process of spraying the toxin-containing water into the air under a water canopy.

Lake Shasta is the largest artificial reservoir in California, supplying both drinking water and agricultural water for much of Northern California. Because of the lake’s enormous water capacity—550 billion gallons—officials declared that the spill would pose no danger to humans and that the water supplied by the lake would be safe to drink.

Officials at the Southern Pacific Railroad Southern Pacific Railroad quickly changed the company’s policy to lower to 3,600 tons the maximum weight that a train can pull without the use of a pusher engine at the rear of the train. Had a pusher engine been in use on the ill-fated train, it likely would not have lost traction, and the accident that caused the spill could have been averted. Railroad officials also promised to pay compensation for the environmental damage caused by the spill and urged restocking of the river with hatchery trout as soon as possible to minimize the economic damage to the region.

If the death of the Sacramento River was a frightening reminder of how the modern industrial world can destroy an ecosystem in a moment, the rebirth of the river was a reminder of the resilience of nature. Within five months of the disaster, diatoms—tiny single-celled plants—were collecting on rocks in the river, and fly larvae were found at the bottom of the river. Full recovery, however, took much longer; some aspects were still ongoing in the early years of the twenty-first century.

The Sacramento River’s recovery from this disaster sparked immediate debate about the extent to which human intervention should be used to accelerate the recovery and ultimately how possible modes of intervention would affect the ecosystem of the river. Among the interventions considered were the use of various methods of stocking trout and the option of not stocking trout at all. Leo Cronin, western regional vice president of Trout Unlimited, Trout Unlimited a nonprofit organization concerned with trout conservation, proposed not stocking any trout in the Sacramento River. Trout fry from the spring spawning were still in the smaller tributaries of the Sacramento River, where they were unaffected by the chemical spill. Cronin argued that if the trout were allowed to repopulate the river naturally, the trout population would remain genetically the same as the wild trout population before the spill, although it would take years to restore the trout population to its level before the spill.

Dick May, the president of California Trout, Incorporated, California Trout, Incorporated a leading lobbying group, proposed taking some of the wild trout upstream of the spill site, breeding them in hatcheries, and replacing the trout one generation at a time with hatchery-raised trout genetically equivalent to the wild trout existing in the river before the spill. This scenario would maintain the genetic integrity of the trout population while hastening the recovery of the river and the return to an economically viable sportfishing industry. Cronin rejected this idea on the grounds that hatchery-raised trout do not possess the same self-preservation skills that wild trout do, as only the fittest of the wild trout survive to adulthood.

The most expedient method, proposed by the Southern Pacific Railroad and many local businesses, would be to stock the river with hatchery-bred and hatchery-raised rainbow trout; this option would provide the most rapid return to an economically viable fishery. Both Cronin and May rejected this idea, arguing that stocked hatchery trout would eat the remaining wild trout fry, thus eliminating the native strain of trout in the Sacramento River.

Another dimension to the issue of restoring trout to the river concerned other wildlife. Not only was sportfishing affected by the death of the trout, but the eagles that populated the valley also lost their primary food supply. If hatchery trout were released into the river, they would provide food for the eagles and could provide prey for sportfishing. Trout, however, are relatively high on the food chain. Because there would be no other source of food for stocked trout until the lower organisms on the food chain reestablished their populations, the trout would eat any food that migrated into the area, including the young trout migrating into the river from the tributaries, or would move downstream until they found a suitable food source. This could both eliminate the source of native trout existing as fry in the tributaries and leave the river without fish as the stocked fish migrated downstream into Lake Shasta in search of food.

The compromise solution that was finally reached was a novel one. Hatchery trout were placed in pens in the river to provide for the eagles, and the river was closed to fishing while the native trout population was allowed to recover.


The Sacramento River metam sodium spill had important short-term impacts: the disruption of an ecosystem and the disruption of the lives of people living in the area who were dependent, perhaps more than they realized, on the river. These impacts were met by short-term solutions directed at particular problems; these included the initial cleanup of the chemical spill and efforts to restore and monitor the river.

The Southern Pacific Railroad quickly provided $2 million for cleanup operations. The EPA, along with the Department of Agriculture and the Department of the Interior, ultimately sued the Southern Pacific Railroad and other companies implicated in the disaster for $40 million.

When a disaster occurs and the short-term remedies have been executed, the next step is to determine how the disaster happened and how it could have been prevented, then to develop long-term strategies both for dealing with a similar disaster in the future and for preventing the occurrence of future disasters. In 1990, more than 1.5 million railroad carloads of pesticides, solvents, and hazardous materials were hauled in the United States, and 1,254 spills of toxic materials occurred from railroad operations that year, but none was as devastating as the Sacramento River spill.

Metam sodium was not classified as a hazardous chemical by either the EPA or the U.S. Department of Transportation. The Sacramento River spill focused attention on the shortcomings of the federal laws and regulations dealing with hazardous chemicals, in particular the issue of what constitutes a hazard. The Toxic Substances Control Act of 1976 Toxic Substances Control Act (1976) specifically excluded pesticides from its jurisdiction. The Federal Insecticide, Fungicide, and Rodenticide Act of 1972 Federal Insecticide, Fungicide, and Rodenticide Act (1972) required the EPA to register the more than fifty thousand pesticides in use in the United States and to limit severely or ban the most dangerous pesticides. Metam sodium was listed by the EPA, but the agency still did not consider the substance dangerous. In the aftermath of the accident, however, it was revealed that the EPA had overlooked warnings on at least ten chemicals, including metam sodium.

The Hazardous Materials Transportation Act of 1975 Hazardous Materials Transportation Act (1975) established minimum safety standards for the transport of hazardous material, but metam sodium was not considered hazardous under the guidelines of the act. The regulations that classified chemical hazards were written primarily in regard to human populations and were based on flammability, explosion hazard, and toxicity to humans; environmental risks were not generally considered. After the metam sodium spill, critics noted that the train manifest listed the contents of the tank car simply as a weed killer, without any hazard warnings or spill procedures; the tank car was not even required to display a placard identifying its contents. Had the contents of the tank car, and the dangers of metam sodium, been known at the accident site, the spill’s effects might have been minimized.

The pesticide spill in the Sacramento River also raised concerns about the technology of the tank cars that carry potentially dangerous materials. The tank car that spilled the metam sodium had a typical single-walled tank that ruptured relatively easily as a result of the derailment. The accident opened debate on the technology and operating practices used by the rail transportation industry in transporting hazardous materials. Disasters;chemical contamination Sacramento River pesticide spill Pesticides Ecological disasters

Further Reading
  • citation-type="booksimple"

    xlink:type="simple">Carson, Rachel. Silent Spring. 1962. Reprint. Boston: Mariner Books, 2002. The book that first popularized environmental concerns, in particular the dangers of pesticides.
  • citation-type="booksimple"

    xlink:type="simple">Dorn, Dick. “The Other Side of Cantara.” Trains Magazine 53 (May, 1992): 27. Argues that public officials overreacted to the spill and that the news media treated the story in a sensationalist manner.
  • citation-type="booksimple"

    xlink:type="simple">Elmer-Dewitt, Philip. “Death of a River: An Ecological Catastrophe in California Points to the Need for New Rules on the Transport of Toxic Compounds.” Time, July 29, 1991, 24. Argues that the spill demonstrated the need for new regulations for the transport of materials that may be hazardous to the environment but are not considered hazardous to humans.
  • citation-type="booksimple"

    xlink:type="simple">Powell, Mark R. Science at EPA: Information in the Regulatory Process. Washington, D.C.: Resources for the Future, 1999. In-depth examination of the EPA includes discussion of how the agency acquires and uses science for policy making.
  • citation-type="booksimple"

    xlink:type="simple">Rosenbaum, Walter A. Environmental Politics and Policy. 6th ed. Washington, D.C.: Congressional Quarterly Press, 2004. Good resource provides background that clarifies how politics can produce policies that allow a material such as metam sodium to destroy an ecosystem and yet not be considered hazardous.
  • citation-type="booksimple"

    xlink:type="simple">Thomas, David. “Sacramento River Killed: Nearly Fifty Miles of Blue Ribbon Water Destroyed by Chemical Spill.” Fly Fisherman 23 (December, 1991): 10-16. Presents an excellent overview of the accident and the controversy surrounding the restocking of the river with trout.
  • citation-type="booksimple"

    xlink:type="simple">Van Strum, Carol. A Bitter Fog: Herbicides and Human Rights. San Francisco: Sierra Club Books, 1983. Discusses the use of herbicides from an environmentalist viewpoint. Includes an interesting chapter titled “Poisons: Innocent Until Proved Guilty” that deals with the process and ramifications of the EPA’s actions in determining the safety of a pesticide.

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