"There was tuna in my diet every day, just about," Porrazzo said. "I thought it was the cleanest source of protein."

Porrazzo, 48, claims he was struck with mysterious symptoms of chest pains than sent him to the hospital "believing he was having a heart attack," a lawsuit filed in U.S. District Court in White Plains said.

His doctor ordered a "heavy metals" blood test in October 2008 that showed "dangerously high" mercury levels of 23 micrograms per liter, more than twice the normal amount, Porrazzo's suit says.