SEATTLE -

Health officials closed Quartermaster Harbor on Vashon-Maury Island to shellfish harvesting after an unsafe level of poison was detected.

The Washington State Department of Health closed the harbor on Wednesday to recreational shellfish harvesting. The closure includes clams, geoduck, scallops, mussels, oysters and snails.

It doesn't include crab or shrimp.

Officials ordered the closure after Paralytic Shellfish Poison, or PSP, was found to be at unsafe levels in shellfish there. PSP poisoning can be life-threatening. Symptoms usually start 30 minutes to an hour after eating contaminated shellfish. Anyone fearing that they've eaten contaminated shellfish should contact the Washington Poison Center.