Largest Heroin Bust in U.S. Is Reported : Drugs: About 1,200 pounds are seized at Hayward warehouse. Four suspects are arrested.

Authorities arrested four suspected members of a drug-smuggling ring and seized 1,200 pounds of heroin Thursday in what U.S. Customs agents described as the largest heroin seizure in U.S. history.

The China white heroin was seized from a Hayward warehouse that had been under surveillance for a month, the Hayward Daily Review reported, quoting unnamed Drug Enforcement Administration sources.

Search warrants also were executed at homes of suspected ring members in Tracy and Blackhawk and at a San Leandro company believed to be associated with the warehouse, the newspaper said.

U.S. Customs spokesman Mike Fleming in Los Angeles confirmed that the heroin seizure was the largest in U.S. history, but he declined to say how much was seized or its value. U.S. Customs Commissioner Carol Hallet scheduled a 3:30 p.m. news conference today at the U.S. Customs House in San Francisco to release details, Fleming said.

Media reports of the drugs’ value ranged from $2.5 billion to $3 billion.

In the largest previous heroin bust, federal officials in New York City seized 800 pounds of Asian heroin worth an estimated $1 billion in early 1989.

In what was decribed as the largest narcotics haul ever, federal agents seized 21.4 tons of cocaine in a Sylmar warehouse in September, 1989. The value of the cocaine was placed at $6 billion.

The DEA said the seizure represented about 5% of the world’s annual production of the drug--more cocaine than growers in Peru, the world’s largest supplier, produce in a year. Three men were convicted a year later on trafficking and conspiracy charges in the seizure.

KGO-TV in San Francisco reported that all of Thursday’s arrests were made at the Join Sun Corp. warehouse in Hayward where nearly three-quarters of a ton of heroin was seized. Names of the suspects were not released.

The drug was smuggled from Thailand to Taiwan, then placed aboard a ship and brought to the Port of Oakland and transferred to the warehouse, the Daily Review reported.

Agents had been keeping a 24-hour stakeout of the warehouse for more than a month, and struck on Thursday after watching three men enter the warehouse, the newspaper said.

Officers rushed onto the roof and to the front and back of the building, witnesses told the Daily Review.

DEA and U.S. Customs agents took part in the stakeout, along with Hayward and San Leandro police.

The Join Sun Corp. moved into the warehouse space about seven months ago and imported porcelain from China, a neighboring businessman told the Daily Review.

Workers told the newspaper they would occasionally see people go to the warehouse, but seldom saw much activity there. One businessman said that at about 9 p.m., June 11, a large group of men worked under high-powered spotlights to load trucks at the Join Sun warehouse.