Coal runoff may affect fish caught recreationally in inland waterways and freshwater, but the commercial seafood consumed by most Americans is caught in the oceans or harvested from aquaculture.

The Sierra Club does not disclose that the trace amount of organic mercury found in commercial seafood comes primarily from underwater volcanoes and mineral deposits. This is not a new phenomenon; de minimis amounts of mercury have been released into the ocean for millennia. In fact, methylmercury levels in commercial seafood are nearly identical to levels recorded over the last 100 years.

They also fail to mention that there has never been any case of mercury toxicity or poisoning in the U.S. attributed to the normal consumption of commercial seafood in any peer-reviewed published medical journal.

The U.S. Food and Drug Administration (FDA) the agency that regulates commercially caught seafood fished from the oceans enforces a 1.0 parts per million (ppm) level of mercury in seafood. To put this in the context of your tuna fish sandwich, canned albacore tuna contains 0.35 ppm mercury and canned light tuna contains 0.13 ppm, putting both types nearly three times lower than the FDA safety level.