Washington State health officials issued an emergency closure for harvesting and ordered a recall for all shellfish originating from a portion of Mason County’s Hammersley Inlet after several people who ate raw oysters became ill.

At least a dozen people who ate raw oysters in November became ill with symptoms often linked to norovirus, a common stomach virus that spreads easily through contaminated food or surfaces and person-to-person contact. Laboratory tests confirmed norovirus in two cases.

The Department of Health used its shellfish tracking system, which tags all commercially harvested shellfish with harvest locations and dates, to investigate the situation. Agency staff visited several shellfish harvest sites and took shellfish samples, one of which later tested positive for norovirus. During the investigation no apparent sources of contamination were identified among companies in Hammersley Inlet that harvest and ship shellfish. During a site visit of the surrounding properties, officials found a leaking septic system that may be the source of the problem. The property owner is working with the Mason County Health Department to permanently repair the failing system while a temporary fix has been put in place.

“This issue underscores the importance of protecting our water and shellfish with good sewage management, especially on properties near shellfish growing areas and their tributaries,” said Jerrod Davis, director for the Office of Shellfish and Water Protection. “Even one failing system can have serious consequences for the safety of our shellfish.”

All shellfish from the noted area are being recalled for the dates of November 10 to December 5. Shellfish included in the recall were sent to several states, including Oregon, Nevada, Florida, Minnesota, Illinois, California, New York, Maine, Georgia, Massachusetts, New Jersey and Virginia.