Three people have been charged with conspiring to illegally export to Iran and China a superstrong material called carbon fiber that can be used to make machines that can enrich uranium, federal prosecutors in Manhattan said on Wednesday.
Iran has been pursuing carbon-fiber technology for years, and has had difficulty in obtaining the material. Enriched uranium can be used as fuel for nuclear reactors and atom bombs.
Another man was charged in a purported scheme to illegally export to Iran via South Korea components for helicopters that could be used for military purposes, the authorities said.
Three of the four men have been arrested. One of them, Hamid Reza Hashemi, 52, a dual United States and Iranian citizen who runs a company in Tehran that the United States government says has been trying to obtain carbon-fiber technology, was arrested on Saturday at Kennedy International Airport as he entered the country, prosecutors said.
Another defendant, Peter Gromacki, 48, of Middletown, N.Y., was accused of arranging for the export of more than 6,000 pounds of carbon fiber from the United States to China via Belgium, in violation of federal law, the government said.
“The law prohibits the exportation of goods to Iran and certain goods to China,” said George Venizelos, who heads the Federal Bureau of Investigation’s New York office.
A third defendant, Amir Abbas Tamimi, 40, an Iranian accused in the purported helicopter-component deal, was arrested at Kennedy Airport in October, the authorities said. He and Mr. Hashemi are being held without bond, while Mr. Gromacki was released on bond, the government said.
The fourth defendant, Murat Taskiran, a Turk accused in the purported carbon-fiber scheme, has not yet been arrested.
The charges do not specify precisely what the government believes the carbon-fiber technology was going to be used for in Iran.
But Preet Bharara, the United States attorney in Manhattan, whose office is prosecuting the men, said “carbon fiber in the wrong hands poses a serious threat” to the national security of the United States.
“Two of these defendants are charged with arranging its export to Iran, where it most assuredly had the potential to end up in the wrong hands,” Mr. Bharara said.
The government charged that in March and April 2008, Mr. Hashemi and Mr. Taskiran worked with an unidentified European broker to arrange for the shipment of carbon fiber from the United States to Iran through Europe and Dubai.
Carbon fiber is used to make rotors for centrifuges, which are used to enrich uranium.
The government also charged that this year Mr. Hashemi sent messages to the European broker, indicating that he wanted to travel to the United States to see a carbon-fiber-winding machine that he wanted to buy. Such machines can be used to make the rotors.
Lawyers for the three men who have been arrested could not be reached for comment Wednesday evening.