In December of 2013 China banned all shellfish exports from the US west coast. In Poverty Bay, Washington inorganic arsenic and in Ketchikan, Alaska Paralytic Shellfish Poisoning toxin were found in geoduck.
Inorganic arsenic found naturally in rock, in the air, or areas where arsenic was used in agriculture. The US doesn’t have an action level for inorganic arsenic however China is concerned about levels of arsenic found in food.
The Asarco smelter facility in Tacoma was thought to be a possible source of arsenic because of its proximity to the Poverty Bay site.
Testing of geoducks showed arsenic is concentrated mostly in the skin. Wild geoduck tracts and farm sites were tested for arsenic showed 8 wild sites in WA and 6 sites in AK showed elevated levels of arsenic.
Each harvest area must be tested and pass to be issued an export certificate to China.