The California Department of Public Health (CDPH) is warning consumers not to eat recreationally harvested bivalve shellfish (such as mussels, clams or whole scallops) from Monterey or Santa Cruz counties due to dangerous levels of a naturally occurring toxin that can cause illness or death. Dangerous levels of domoic acid have been detected in mussels from this region. This toxin, also known as Amnesic Shellfish Poisoning (ASP), can cause illness or death in humans. No cases of human poisoning from domoic acid are known to have occurred in California. This warning, issued Friday, does not apply to commercially sold clams, mussels, scallops or oysters from approved sources. State law permits only state-certified commercial shellfish harvesters or dealers to sell these products. Shellfish sold by certified harvesters and dealers are subject to frequent mandatory testing to monitor for toxins. Symptoms of domoic acid poisoning can occur within 30 minutes to 24 hours after eating toxic seafood. In mild cases, symptoms may include vomiting, diarrhea, abdominal cramps, headache and dizziness. These symptoms disappear within several days. In severe cases, the victim may experience trouble breathing, confusion, disorientation, cardiovascular instability, seizures, excessive bronchial secretions, permanent loss of short term memory, coma or death. To receive updated information about shellfish poisoning and quarantines, call CDPH’s toll-free “Shellfish Information Line” at (800) 553-4133. For additional information, visit CDPH’s Natural Marine Toxins: PSP and Domoic Acid Web page.