County health authorities just announced that the state Health Department has closed beaches to shellfish harvesting from “Alki Beach south to the Pierce County line, including Vashon Island and Quartermaster Harbor beaches.” Here’s the full text of the news release:

Paralytic Shellfish Poison (PSP) has been detected at unsafe levels in shellfish on Vashon Island and at the Des Moines Marina. As a result, the Washington State Department of Health (DOH) has closed Alki Beach south to the Pierce County line, including Vashon Island and Quartermaster Harbor beaches, to recreational shellfish harvest.

The closure includes all species of shellfish including clams, geoduck, scallops, mussels, oysters, snails and other invertebrates; the closure does not include crab or shrimp. Crabmeat is not known to contain the PSP toxin, but the guts can contain unsafe levels. To be safe, clean crab thoroughly and discard the guts (“butter”). Working with partners, Public Health – Seattle & King County is posting advisory signs at beaches warning people to not collect shellfish.

Commercial beaches are sampled separately and commercial products should be safe to eat.

Anyone who eats PSP contaminated shellfish is at risk for illness. PSP poisoning can be life-threatening and is caused by eating shellfish containing this potent neurotoxin. A naturally occurring marine organism produces the toxin. The toxin is not destroyed by cooking or freezing.

A person cannot determine if PSP toxin is present by visual inspection of the water or shellfish. For this reason, the term “red tide” is misleading and inaccurate. PSP can only be detected by laboratory testing.

Symptoms of PSP usually begin 30-60 minutes after eating the contaminated shellfish, but may take several hours. Symptoms are generally mild, and begin with numbness or tingling of the face, arms, and legs. This is followed by headache, dizziness, nausea, and loss of muscle coordination. Sometimes a floating sensation occurs. In cases of severe poisoning, muscle paralysis and respiratory failure occur, and in these cases death may occur in 2 to 25 hours.

If symptoms are mild, call your health care provider or Washington Poison Center (800-222-1222), and Public Health (206-296-4774). If symptoms are severe, call 911 or have someone take you to the emergency room immediately.

Recreational shellfish harvesting can be closed due to rising levels of PSP at any time. Therefore, harvesters are advised to call the DOH Biotoxin Hotline at 800-562-5632 or visit the Shellfish safety website before harvesting shellfish anywhere in Puget Sound.