WASHINGTON – The Food and Drug Administration told California this week that the state’s attempt to require mercury warnings on tuna conflicts with federal law.

California’s attorney general disputed the FDA letter Friday, and said it was an attempt to stop a lawsuit the state has filed against tuna companies over the warnings.

“The federal government has no authority to prevent California, or any state, from requiring warnings that provide truthful, important information to consumers,” said Tom Dresslar, spokesman for California Attorney General Bill Lockyer.

A year ago, Lockyer sued the nation’s three largest canned tuna companies to enforce Proposition 65, California’s 1986 law requiring businesses to provide “clear and reasonable” warnings when they expose consumers to known reproductive toxins, such as mercury.

The companies are Tri-Union Seafoods, maker of Chicken of the Sea; Del Monte, maker of Starkist; and Bumble Bee Seafoods.