If activists have their way, supermarket chains in California will end up paying $2,500 in fines for every day they sold fish without “warning labels” about mercury. The Turtle Island Restoration Network, a spin-off of the money-grubbing Earth Island Institute and one of the two groups to initiate a lawsuit against the supermarkets, says it wants to “inform the public of the health hazards of mercury in fish.” But the government agencies whose job it is to warn the public about such things tell a different story.

The California Office of Environmental Health Hazard Assessment says: “The levels of methyl mercury in California fish are much lower than those that occurred in Japan… We are not aware of any cases of overt poisoning in California, nor would we expect them.”

So why is a group whose stated mission is saving sea turtles all worked up about human health? It turns out that they’re interested in destroying the swordfish market, because they think it hurts turtle populations. They admit as much on their own website, where you can find campaigns targeting specific restaurant chains who dare to put swordfish on the menu.

Of course, these activists also happily mislead the public about the dangers of mercury. In August they took out a full page ad in the New York Times warning that “swordfish [and other fish] contain enough mercury to harm the central nervous system.”

The Centers for Disease Control (CDC) recently released a landmark study on chemicals in the human body, which showed “total blood mercury levels” among Americans at “well below occupational thresholds of concern.”Not a single woman (the most “at-risk” population) had blood mercury measured above the CDC’s “danger” levels. The New York Times reported that “all other population groups, including children, had blood levels of mercury well below the government safety limit.”

Health officials frequently point out that low levels of most chemicals, including mercury, are safe for humans. The CDC report reinforces this point: “Finding a measurable amount of mercury in blood or urine does not mean that the level of mercury causes an adverse health effect.” Even scary-sounding chemicals like arsenic naturally occur in the human body and are essential to human growth. If you listened to scaremongers like the Environmental Working Group (EWG) however, you’d be surprised that ordinary chemicals haven’t already killed us all.

EWG placed a full-page ad in the New York Times on Wednesday — timed to coincide with the myth-busting CDC report — trumpeting the claim that dozens of harmful chemicals are typically found in the human body. A woman pictured in the ad later complained in the San Francisco Chronicle that “we’re living in a toxic stew and they [chemical companies] are, quite literally, getting away with murder.” Accusations of murder are farfetched, to put it charitably. For starters, the EWG study was based on people who are very much alive.

Unlike the CDC study, EWG’s Times advertisement contained not one word about levels of the purportedly murderous chemicals. Remember — it’s the dose that makes the poison. Also unlike the extensive CDC study, EWG tested only nine people, all of them like-minded activists. One of the people EWG tested was Michael Lerner, President of Commonweal, an activist group that — surprise, surprise — co-sponsored the EWG study.

EWG’s Times ad sneers at the CDC’s view that trace amounts of some chemicals in our bodies are “too small to cause disease.” Instead, EWG tries to sneak the Precautionary Principle in through the back door, challenging chemical companies to “prove it with sound science before people are exposed.” According to this worldview, we would no longer be able to use a host of everyday products, including ink, batteries and fire extinguishers. And, of course, we’d no longer be able to eat fish.