JINAN, May 3 (Xinhua) -- Twenty one people have been caught in east China's Shandong province for smuggling ferrosilicon, said local customs on Wednesday.

They are suspected of smuggling as much as 80,000 tonnes of ferrosilicon worth 650 million yuan (95 million U.S. dollars), according to Qingdao customs.

On April 14, the ship registered as Fushun 16 appeared in Shandong. More than 150 customs and police officers intercepted the ship and caught the suspects.

A total of 2,350 tonnes of ferrosilicon were seized in the ship. More was confirmed to have been sold or stored for smuggling.

A preliminary investigation showed that the ship was registered twice, domestically and internationally. Under the domestic registration it finished loading, allegedly claiming that the cargo was construction materials.

After the ship left China, it was to be repainted under the name of its international registration, carrying the ferrosilicon to Japan and Republic of Korea, the customs said.

Ferrosilicon is a material used in foundries. China is one of the major suppliers of ferrosilicon in the world. To reduce the effect of ferrosilicon production on the environment, China has restricted exports of ferrosilicon since 2005.

The case is under further investigation.