(AP) -- Shrimp, grouper, tuna and other seafood snatched from the fringes of the oil in the Gulf of Mexico are safe to eat, according to a federal agency inspecting the catch.
To date, roughly 400 samples of commonly consumed species caught mostly in open waters - and some from closed areas - have been chemically tested by the National Oceanic and Atmospheric Administration. Officials say none so far has shown concerning levels of contaminants. Each sample represents multiple fish of the same species.
NOAA and the Food and Drug Administration began catching seafood species in the Gulf within days of the April 20 BP rig explosion off Louisiana that generated a massive oil spill.
The agency is mostly looking for polycyclic aromatic hydrocarbons, or PAHs, the most common carcinogenic components of crude oil.
The first line of defense in keeping tainted seafood from the market is the closing of about one-third of federal Gulf waters to commercial fishing - roughly 80,000 square miles.
Seafood inspectors also have been trained to sniff out oily product. One fish sample has failed the smell test, but did not show concerning levels of contaminants, Kevin Griffis of the Commerce Department said Friday.
Still, Don Kraemer, who is leading FDA's Gulf seafood safety efforts, said the government isn't relying on testing alone.
"We couldn't possibly have enough samples to make assurances that fish is safe. The reason we have confidence in the seafood is not because of the testing, it's because of the preventive measures that are in place," such as fishing closures, he said.
FDA issued guidance last month that encourages seafood processors to heighten precautions so they know the origin of their seafood.
The federal government plans surprise inspections at docks along the Gulf Coast, though Dr. Steve Murawski, NOAA's chief scientist, acknowledged they can't be everywhere.
"It's like enforcing anything. You can't be everywhere all the time and handle every fish. We're going to try to be real visible," Murawski said.
Explore further: Federal agencies say seafood safe