Oregon authorities have expanded shellfish harvesting closures along the state’s entire coastline to include razor clams and bay clams, as already high levels of toxins that have contributed to a shellfish poisoning outbreak continue to rise.

The Oregon Department of Fish and Wildlife said the new closures were due to “historic high levels” of a marine biotoxin known as paralytic shellfish poisoning. The move, announced by the department in a news release on Thursday, came after state officials similarly closed the whole coast to mussel harvesting last week.

Agriculture officials have also closed an additional bay on the state’s southern coast to commercial oyster harvesting, bringing the total of such closures to three.

Elevated levels of toxins were first detected in shellfish on the state’s central and north coasts on May 17, fish and wildlife officials said.