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PCBs in Farmed Salmon

PCBs in Farmed Salmon

Test results show high levels of contamination
Thursday, July 31, 2003

Summary — PCBs in farmed salmon

Seven of ten farmed salmon purchased at grocery stores in Washington DC, San Francisco, and Portland, Oregon were contaminated with polychlorinated biphenyls (PCBs) at levels that raise health concerns, according to independent laboratory tests commissioned by Environmental Working Group.

These first-ever tests of farmed salmon from U.S. grocery stores show that farmed salmon are likely the most PCB-contaminated protein source in the U.S. food supply. On average farmed salmon have 16 times the dioxin-like PCBs found in wild salmon, 4 times the levels in beef, and 3.4 times the dioxin-like PCBs found in other seafood. The levels found in these tests track previous studies of farmed salmon contamination by scientists from Canada, Ireland, and the U.K. In total, these studies support the conclusion that American consumers nationwide are exposed to elevated PCB levels by eating farmed salmon.

Farmed Salmon has forty times the PCBs that other food have informational graphic

PCBs are persistent, cancer-causing chemicals that were banned in the United States in 1976 and are among the “dirty dozen” toxic chemicals slated for global phase-out under the United Nations Convention on Persistent Organic Pollutants, signed by President Bush on May 23, 2001. Because of their persistence, PCBs continue to contaminate the environment and the food supply.

A number of studies show that farmed salmon accumulate PCBs from the fishmeal they are fed. The feed is often designed to have high amounts of fish oil and is made largely from ground-up small fish. PCBs concentrate in oils and fat, and previous tests of salmon feed have consistently found PCB contamination.

If farmed salmon with the average PCB level found in this study were caught in the wild, EPA advice would restrict consumption to no more than one meal a month. But because farmed salmon are bought, not caught, their consumption is not restricted in any way.

This is because the EPA sets health guidance levels for PCBs in wild-caught salmon, and its standards, which were updated in 1999 to reflect the most recent peer-reviewed science, are 500 times more protective than the PCB limits applied by the Food and Drug Administration (FDA) to commercially-sold fish. The FDA has not updated its PCB health limit for commercial seafood since it was originally issued in 1984. In the intervening two decades new scientific research has shown that the PCBs that build up in fish and people are more potent cancer-causing agents than originally believed, and that they present other health risks as well, in particular neurodevelopmental risks to unborn children from maternal consumption of PCB-contaminated fish.

When the FDA’s standard was developed, salmon was something of a rarity in the U.S. diet. Today it is standard fare at home and in restaurants, particularly among consumers who are health-conscious, well educated, and relatively affluent. Last year salmon overtook “fish sticks” as the third most popular seafood in the American diet (trailing only tuna and shrimp). The increased consumption was made possible by the explosive growth in salmon farming, an industrial system that produces the fish in vast quantities at a price far lower than wild salmon.

Seven of the farmed salmon we tested came from factory-scale farms in Canada, the U.S., and Iceland. Six of these seven were polluted with PCBs at levels that would be safe to eat no more than once a month, according to EPA health standards. About 23 million Americans eat salmon more than once a month, the majority of it farmed salmon. One salmon imported from Scotland contained PCBs at levels so high that EPA would restrict consumption to no more than six meals a year, if the salmon were caught, not bought.

The farmed salmon industry claims that both farmed and wild salmon can be eaten safely more than once a week. This claim relies on FDA’s outdated contamination limit. In EWG’s testing program, nine of 10 farmed salmon tested from five countries of origin failed EPA’s health-based limits for weekly consumption (6000 parts per trillion), exceeding the standard by an average of 4.5 times. A pilot study published by Canadian scientists last year showed that farmed Canadian salmon contain ten times the PCBs of wild Alaskan and Canadian salmon.

EWG’s analysis of seafood industry fish consumption data shows that one quarter of all adult Americans (52 million people) eat salmon, and about 23 million of them eat salmon more often than once a month. Based on these data we estimate that 800,000 people face an excess lifetime cancer risk of more than one in 10,000 from eating farmed salmon, and 10.4 million people face a cancer risk exceeding one in 100,000. The government's preferred level of increased risk from contaminants like PCBs is no more than one in one million, a threshold set to account for a regulatory system that addresses chemicals or chemical classes individually and is unable to set safe levels for the complex mixtures of hundreds of industrial chemicals to which people are exposed.


Six of every ten salmon sold in stores and restaurants are raised in high-density fish pens in the ocean, managed and marketed by the salmon farming industry. These fish are eaten by a quarter of all adults in the U.S. and experts predict that the exponential growth of the farmed salmon industry will continue.

Farm-raised fish are here to stay. If raised correctly, these fish can help meet global demand for high-quality protein and take some of the pressure off of highly depleted populations of wild fish. But major reforms to the industry are needed.

In addition to the well documented ecological problems with salmon farming, there is now compelling evidence of near industry-wide contamination with unacceptably high levels of PCBs.

To remedy this problem, we recommend that:

  • Congress pass a funding increase for FDA to support testing of farmed salmon and other protein sources for PCBs.
  • The Food and Drug Administration move quickly to conduct a definitive study of PCB contamination in farmed salmon, and make all results public. This testing is critical, because FDA will be unable to update its regulation on PCBs in farmed salmon until the agency conducts its own laboratory studies.
  • The FDA issue a PCB health advisory for seafood consumption in line with current PCB health guidance issued by the EPA.
  • Policy-makers do more to preserve salmon habitat in Alaska, where, preliminary indications are, fish are naturally low in PCB contamination.
  • The salmon farming industry monitor salmon feed for PCB contamination and shift or refine feed sources to produce fish lower in PCBs and other pollutants.

What you can do

To reduce your exposure to PCBs, trim fat from fish before cooking. Also, choose broiling, baking, or grilling over frying, as these cooking methods allow the PCB-laden fat to cook off the fish. When possible, choose wild and canned Alaskan salmon instead of farmed, and eat farmed salmon no more than once a month.

Key Issues, Toxics, Health Concerns: