China has blocked imports of shellfish harvested from the U.S. West Coast over reports of arsenic and toxins found in geoduck clams.
The shellfish are believed to have originated from waters off Washington or Alaska, according to KUOW public radio.
"They've never done anything like that, where they would not allow shellfish from this entire area based on potentially two areas or maybe just one area. We don't really know yet," Jerry Borchert of the Washington Department of Health told the Seattle-based KUOW.
The U.S. exported $68 million worth of geoduck clams last year, mostly from Washington's Puget Sound, according to the Associated Press.
About 90% of those geoduck exports went to China, where the elephant trunk-shaped clams are prized as delicacies. A prolonged ban from the Chinese market could be devastating to the shellfish industry in the Pacific Northwest.
"It's had an incredible impact," George Hill, the geoduck harvest coordinator for Puget Sound's Suquamish Tribe, told KUOW. "A couple thousand divers out of work right now."
China has been trying to improve its food safety after years of production scandals. The world's No. 2 economy is also one of the largest exporters of farmed fish. But China also suffers from notoriously polluted waters, which have led to contamination fears in its seafood.
China still prohibits imports of American beef because of links to mad cow disease a decade ago. Last month, China blocked imports of unapproved genetically modified U.S. corn.