Recent laboratory tests in New York found so much mercury in tuna sushi that two or three pieces a week at some restaurants could be a health hazard.
Eight out of the 44 pieces of sushi purchased by the New York Times for testing had mercury levels so high that the FDA could take legal action to remove the fish from the market.
Although all the samples were obtained in New York City, experts believe similar results would also be observed elsewhere.
While the FDA and EPA have warned children and pregnant women against consumption of canned tuna, fresh tuna was not included in the advisory. However, the tuna sushi in The New York Times sample contained far more mercury than is typically found in canned tuna.
The scientists who performed the analysis said they were "frankly surprised" by the results, and that they had run the tests several times to make sure there was no mistake.