In what is believed to be the world's largest single heroin seizure, Thai authorities reported the interception of 1.4 tons of top-grade heroin bound for New York and worth more than $2 billion on the street. The 2,822 pounds of No. 4 grade heroin was hidden in bales of rubber sheets on a freighter at Klong Toey Port in Bangkok, the director general of customs said. No. 4 grade heroin is 97% pure. The drug was discovered when customs inspectors, acting on a tip, began opening the 665 bales, the official said. The previous largest heroin bust was 2,640 pounds, seized in France in 1972.