Introduction

Methyl iodide or ‘Mel’ is a dense, colourless, volatile monohalomethane, which is rapidly metabolised in man (Ofigures 1 and 2); the organically bound iodine is converted to inorganic iodide and excreted in this form in the urine.1 It is used as a pesticide in the USA and in a variety of organic chemical reactions and for dye-works and detergents in the UK. Although methyl iodide is a rare intoxicant, its manifestations are similar to those of poisoning with the other more common monohalomethane agents. Indeed, methyl iodide intoxication resembles that of methyl bromide and methyl chloride. Characteristics of the poisoning include a delay between exposure and onset of symptoms with early systemic toxicity, including congestive changes in the lungs and oliguria; metabolic acidosis; prominent cerebellar and extrapyramidal neurological features; and in severe cases, seizures and coma. Psychiatric disturbances may persist for years.