Is carbaryl as safe as its reputation? Does it have a potential for causing chronic neurotoxicity in humans?

The observation of neurotoxicity in a subject with long-term exposure to high levels of carbaryl has prompted the review of the potential for carbaryl to cause toxicity. Short-term studies in animal species and humans confirm that carbaryl can cause toxicity due to cholinesterase inhibition. Wide variations in the dosage required to induce toxicity in either different species or in one species by different routes of administration can in part be explained by differences in drug disposition. However, the information available about carbaryl's disposition in humans is inadequate to interpret the relevance of animal studies to humans. Limited long-term exposure studies in rats and dogs have not demonstrated unexpected adverse effects. However, long-term exposure in pigs results in a progressive neuromyopathy that is associated with structural damage and is not acutely reversible with atropine. Published information on the effects of long-term exposure to carbaryl in humans is limited and has not identified any adverse effects. It is concluded that not enough information is available to exclude the possibility that sustained high levels of exposure to carbaryl could be associated with neurotoxic or myotoxic responses in humans.