A fire retardant once linked to spontaneous combustion in fishmeal cargoes is now under scrutiny for its presence in the global seafood supply. From the 1950s through the 1970s, at least 87 incidents involving fishmeal—used in animal and aquaculture feed—were tied to spontaneous fires on ships, in processing plants, and in warehouses. The culprit was a powdery substance that ignited as it decayed and oxidized. To address the hazard, manufacturers began treating fishmeal with ethoxyquin, an antioxidant originally developed to stabilize rubber tires and preserve fruits.

By the 1970s, the chemical’s effectiveness was clear. Shipboard fires dropped sharply, from about 16 per year to five, according to data from the Liverpool Underwriters Association. The U.S. Coast Guard made ethoxyquin treatment mandatory for fishmeal shipments in 1976, and three years later, the International Maritime Organization recommended its use globally to prevent combustion.

However, concerns about ethoxyquin’s safety emerged early. A 1969 U.N. report noted toxic effects in laboratory animals exposed to high doses, and a 1987 study by British researchers described it as potentially carcinogenic. In 2015, the European Food Safety Authority identified an impurity—p-phenetidine—as capable of causing genetic mutations. By 2017, the European Union banned ethoxyquin in animal feed due to these risks, and it has since been prohibited in the U.K., Norway, Iceland, and Liechtenstein.

Today, ethoxyquin remains permitted in animal feed in the United States, Australia, Japan, and South Korea, though its use is restricted in some contexts. It is still authorized in aquaculture feed in the U.S., where it is used to extend shelf life and reduce fire risk during fishmeal processing. Regulatory agencies require labeling of treated feeds, but monitoring of residue levels in final seafood products is inconsistent. A 2024 audit by the European Commission found that Canadian authorities conducted only about 40 percent of planned inspections, with limited testing for ethoxyquin in seafood.

The chemical has recently become the subject of legal challenges. In 2022, lawsuits were filed against major seafood distributors, including Aldi and Gorton’s, alleging false labeling of products as “sustainable” despite containing ethoxyquin. Plaintiffs cited the European ban and studies linking the additive to environmental harm, including toxicity in aquatic life. Both cases were settled out of court.

While some companies have shifted to alternative preservatives, such as butylated hydroxyanisole (BHA), that compound also carries health concerns. The U.S. National Toxicology Program has classified BHA as “reasonably anticipated to be a human carcinogen,” and studies have shown tumor development in rats exposed to high doses. The FDA is currently reassessing BHA’s safety as a food additive.

Cargill, one of the largest producers of fishmeal and aquafeed, announced in recent years that it no longer uses ethoxyquin in its global salmon feed operations, particularly in markets where its use is restricted. The company emphasized that it did not originally develop the chemical and has been evaluating safer alternatives, including natural antioxidants like rosemary extract and vitamin E.

The transition away from ethoxyquin reflects broader shifts in the aquaculture industry, which now supplies more than half of the world’s seafood. As demand grows, so does scrutiny over the additives used in feed production. While fire risks from untreated fishmeal have diminished, the replacement of one controversial chemical with another underscores the complexity of balancing safety, efficacy, and long-term health impacts in global food systems.