Paraquat — a Review of Safety in Agricultural and Horticultural Use

1 Over the past 20 years plus that paraquat has been used throughout the world, it has enjoyed an excellent safety record when used normally and for its intended purpose. 2 Its safety record is explained by the following reasons: (i) inhalational exposure during normal use is not significant toxicologically; (ii) dermal exposure predominates during normal use; (iii) intact human skin provides a very good barrier against penetration by paraquat. 3 Its safety record has been confirmed by several field studies, which have assessed exposure and health of workers, who have used paraquat for short and longer periods of time. The unanimous conclusions of the studies is that exposure to paraquat does not result in any acute or chronic adverse health effects. 4 Minor and reversible injuries to the skin, eyes, nose and nails do occur and probably result from overexposure to the extremely irritant concentrated formulations. Most of these effects can be avoided using ordinary personal hygiene. 5 There have been a few anecdotal cases reported in the literature when dermal absorption of paraquat has genuinely occurred and led to serious health effects. In all cases prolonged exposure to concentrated paraquat solutions has been involved resulting in severe and extensive skin damage, with removal of the barrier and absorption of lethal amounts of the chemical. 6 Those cases involving exposure to concentrated paraquat solutions emphasise the need to handle such formulations, for example 'Gramoxone', with case and ensure that the spray solution is correctly made up-at a dilution of at least 1 part 'Gramoxone' to 40 parts water.