In July, persons in the US and Canada (Alberta; British Columbia) developed symptoms of poisoning with a cholinesterase-inhibitor. The most severe signs and symptoms included seizures, loss of consciousness, cardiac arrhythmia, hypotension, dehydration, and anaphylaxis. Oregon officials identified aldicarb sulfoxide (ASO) in several watermelons consumed by persons who had been ill. ASO is a systemic carbamate pesticide which was not registered for use on watermelons. It was primarily used in citrus groves and potato fields. Fortunately. inhibition of cholinesterase by carbamates is rapidly reversible with drugs such as atropine. This was the largest outbreak of foodborne pesticide illness.