Monosodium methanearsonate (MSMA) is an organo-arsenic containing herbicide. There is scant information available concerning the toxicity of this chemical in humans.Seven male teenagers, 15-18 years of age, inadvertently used a MSMA herbicide as cooking oil to fry fish. All had early gastrointestinal (GI) symptoms. Whole blood arsenic concentrations ranged from 348 to 613 μg/L and initial urine levels ranged from 81 400 to 226 300 μg-arsenic/g-creatinine. They were all treated with dimercaprol for 1 day and succimer for 19 days. They were followed for 15-months and had no evidence of any serious toxicity.MSMA produces early GI symptoms and very high levels of arsenic in blood and urine, but no evidence of long-term toxicity.
