Whether mothers and children will be warned about the harm from mercury in canned tuna will be decided not based on threats to health or the latest science. Instead, it will hinge on whether a panel of judges believe the tuna industry’s claims that the potent neurotoxin is “naturally occurring” and therefore not needing a label under California’s Proposition 65 chemical “right to know” law. During a court hearing yesterday in San Francsico, the California Attorney General’s office argued that even if only 5 percent of the methylmercury in fish was NOT naturally occuring, it is toxic enough to warrant a warning because it is known to cause cancer and reproductive harm. See the Associated Press story at sfgate.com. No one except the tuna canners dispute that tuna and other fish contain methlymercury or that it’s potentially harmful to pregnant women, unborn babies, children and anyone who eats too much of it. Even the federal government under the Bush Adminstration issued warnings against mercury-laden fish.(Though the FDA staffers who remain are still hoping to repeal the advisory.) It’s also clear the mercury pollution from coal-burning power plants around the world deposit tons of mercury into the atmosphere, which is deposited in the ocean and converted to toxic methylmercury by bacteria. The toxin then is eaten by marine organisms, fish and eventually accumulates in the tissue of large fish. Some of the mercury also occurs naturally in the ocean, scientists believe. Because the tuna industry doesn’t put the mercury in the fish, nor can they take it out, the lobbyists argue that it is naturally occurring and expempt from Proposition 65 warnings. In fact, they want mothers, children and everyone to EAT MORE toxic fish to make sure profits don’t lag. We sure hope that the judges don’t agree. In fact, federal statute has already determined that methylmercury in fish is caused by human activity is not solely naturally occurring. We’ll know in the next 90 days whether people will get the information they need to decide whether or not to buy tuna for their families.