Occupational exposures to pesticides containing organoarsenicals in California

The only organic arsenicals used in agriculture are methanearsonic acid (MSMA) and its sodium and ammonium salts and dimethylarsinic acid (cacodylic acid) and its sodium salt. They have an oral LD50 in the rat of 700-1,000 mg/kg and are classified as toxicity category 3 pesticides. During the three-year period 1975, 1976 and 1977 in California there were 34 reports by physicians of injury due to exposure to pesticides containing organic arsenicals of which nine resulted in systemic symptoms and the remainder being eye and skin irritations. There appeared to be prompt recovery from these exposures. They were caused primarily by use of faulty equipment, not using due care in its operation, poor work practices and improper use of protective equipment. There is no evidence that this group of chemicals is carcinogenic in animals or man.