A Chinese businessman was ordered held without bail Monday after an appearance in federal court in Boston to face charges that he smuggled US-made equipment used to process weapons-grade uranium into Iran.

Sihai Cheng, 34, who had been living in China before his arrest in the United Kingdom earlier this year, faces up to 20 years in prison on charges including conspiracy to export US goods into Iran and illegally exporting goods to Iran. He is also charged with smuggling goods.

Cheng, also known as Alex Cheng and as Chun Hai Cheng, wore what appeared to be sweat pants in his brief appearance before US Magistrate Judge Marianne B. Bowler. He spoke clear English, and said he understood his rights and the charges he faces, though at times he needed an interpreter to understand the judge during the proceeding.


Cheng said he was a businessman involved in international trading for the last decade. He has a bachelor’s degree in English from a university in China, he said.

His lawyer, Stephen Weymouth, said he is still reviewing the charges, and said Cheng would temporarily agree to being detained. Assistant US Attorney Stephanie Siegmann told Bowler that Cheng is a flight risk, has no family in the United States, and no legal immigration status.

Cheng told Bowler that “I have no access to my money,” to hire a lawyer, because his assets are in China.

Cheng was arrested while traveling to the United Kingdom in February and fought his extradition to the United States to face the illegal exportation charges.

Authorities said Cheng led a conspiracy to export hundreds of pressure-measuring sensors, or transducers, into Iran. Transducers are commonly used in manufacturing, but can also be used in gas centrifuges to convert natural uranium into a form suitable for nuclear weapons.

He was charged in a federal court in Boston because the equipment he allegedly smuggled was manufactured by MKS Instruments Inc., an Andover company.


The company was not accused of any wrongdoing.

Cheng allegedly set up a scheme to export the goods to legitimate distribution companies in China. He then created shell companies as the intended recipients of the goods, which were instead delivered to companies in Iran.

The transducers can be distributed to foreign countries with a lawful export license, though they cannot be brought to Iran.

To arrest a foreign national, prosecutors would have to prove that Cheng knowingly and willfully violated US export laws in smuggling US goods.

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Milton J. Valencia can be reached at mvalencia@globe.com. Follow him on Twitter @miltonvalencia.