San Francisco, CA – An undercover investigation of grocery store fish counters led by the non-profit public health project detected hazardous levels of mercury in fresh and frozen fish from 13 San Francisco Bay Area supermarkets. Read the report.

All swordfish samples exceeded the U. S. government’s mercury action level of 1 part per million – and one piece of swordfish registered twice as high. Ahi tuna (yellowfin tuna) also contained alarming amounts of mercury. See the complete mercury-in-fish results by specie .

“Making choices at the seafood counter shouldn’t be a toxic gamble. People have a right to know there could be dangerous levels of mercury in the fish they buy at a grocery store,” said Buffy Martin Tarbox, Campaign Coordinator for, based in Forest Knolls, CA. “Furthermore, the FDA action level is far too high and needs to be lowered to better protect the public.” sampled 24 samples of swordfish, Ahi tuna, halibut and albacore tuna purchased from 13 different grocery stores in San Francisco and Marin County. Micro Analytical Systems, Inc. analyzed the 24 samples for mercury levels in their accredited laboratory facilities located in Emeryville, California.

All fish samples contained mercury and most were above 0.5 parts per million. Ahi tuna (yellowfin) came in second for mercury toxicity among the fish species, with one piece exceeding the action level. Eating fish is the number one source of mercury exposure in the United States, according to the U.S. Environmental Protection Agency.

The free, easy-to-use calculator based on U.S. fish-mercury standards found at can help guide people towards fish that contain lesser amounts of mercury. According to the Got fish calculator, a woman who weighs 140 pounds and eats a six-ounce portion of swordfish this week will be exposed to a mercury level that is 273 percent above government exposure guidelines. A 130 pound woman who ate just one 8 ounce ahi filet this week would exceed her EPA safe level of mercury by nearly 400 percent. A child of 40 pounds, eating the same ahi steak this week, would exceed the EPA safe level of mercury by nearly 1300 percent.

The United States Food and Drug Administration (FDA) has determined that women of child-bearing age and young children should not eat swordfish due to high mercury levels. Yet warning signs were absent from about half the seafood counters. See the FDA advisory. Mercury contamination of seafood is a widespread public health problem, especially for women of childbearing age, pregnant and nursing women and children. Studies have shown that mercury can contribute to memory loss, learning disabilities, and attention deficit disorders and even death.A growing body of evidence suggests that exposure to mercury can lead to heart disease.

Currently there are no federal legal requirements for stores to warn shoppers about mercury in fish although has effectively worked with the California Attorney General to require warning signs be posted at supermarket seafood counters and some restaurants.

Got has been lobbying the California State Legislature, Congress and the FDA to mandate mercury in fish warning signs at grocery stores and restaurants, but government has been slow to act.

About works to protect people and the environment from mercury. Because of the ubiquitous nature of mercury in the environment and because federal and state public health agencies are not doing enough to raise public awareness and protect the public from mercury, developed the free online mercury-in-fish calculators that have received millions of hits since 2002. For more information visit: or