Paraquat poisoning by skin absorption: a review.

All reported cases of paraquat poisoning by absorption through the skin are briefly reviewed. It is concluded that, while paraquat cannot be absorbed significantly through intact human skin, damage to the skin, either by paraquat itself or by other means, will permit greater systemic absorption and possibly poisoning. The lowest known concentration of paraquat to result in fatal poisoning through the skin is 5 g/l. Animal experiments with paraquat are also reviewed. The fact that the reported lethal dermal dose of paraquat in rats is slightly less than the oral dose is probably due to the lack of head restraint on the rats in the dermal dosing experiments. In vivo and in vitro tests on human skin at concentrations of 9 g/l and 5 g/l did not result in significant absorption of paraquat through the skin but in these experiments the skin was intact.