(Chicago Tribune) Supermarkets throughout the Chicago area are routinely selling seafood highly contaminated with mercury, a toxic metal that can cause learning disabilities in children and neurological problems in adults, a Tribune investigation has found.

In one of the nation's most comprehensive studies of mercury in commercial fish, testing by the newspaper showed that a variety of popular seafood was so tainted that federal regulators could confiscate the fish for violating food safety rules.

The testing also showed that mercury is more pervasive in fish than what the government has told the public, making it difficult for consumers to avoid the problem, no matter where they shop.

It is not by happenstance that contaminated fish can be found on shelves and at seafood counters throughout the region, from small neighborhood shops on the South Side to sprawling supermarket chain stores in the northwest suburbs.

The Tribune's investigation reveals a decades-long pattern of the U.S. government knowingly allowing millions of Americans to eat seafood with unsafe levels of mercury.

Regulators have repeatedly downplayed the hazards, failed to take basic steps to protect public health and misled consumers about the true dangers, documents and interviews show.

The government does not seize high-mercury fish that violate U.S. limits. Regulators do not even inspect seafood for mercury--not in ports, processing plants or supermarkets.