**5. Occupational and environmental phosphine exposure**

Occupational exposures to phosphine are uncommon and rarely severe (Sudakin, 2005) but accidental inhalation is a particular risk to those in close proximity to grain that has had a metal phosphide mixed in with it. Recurring locations include ships holds (Gregorakos, et al, 2002, Hansen & Pedersen, 2001, Vohra, et al, 2006), rail wagons (Perotta, et al 1994, Vohra, et al, 2006), grain elevators (Abder-Rahman, et al, 2000), grain stores (Brautbar & Howard, 2002, Misra, et al, 1988), and even stores in homes (Abder-Rahman, et al, 2000). Potentially lethal concentrations of the gas may develop in the head-spaces of unventilated or poorly ventilated storage containers and domestic premises (Memis, et al, 2007).

Phosphine may be released during the illicit manufacture of methamphetamine (Burgess, 2001, Willers-Russo, 1999); deaths have resulted (Willers-Russo, 1999). In another incident, a packet of aluminium phosphide in a container from abroad burst open and the sweepings placed in water causing immediate fizzing and liberation of phosphine (Kamanyire & Murray, 2003). Close proximity to a source of phosphine is not required to be at risk of toxicity as phosphine gas can travel some distance as it is heavier than air (vapor density 1.2:1). Many years ago 12 individuals in a house adjacent to a warehouse used to store aluminium phosphide developed vomiting and one died. The illnesses were attributed to phosphine (Glass, 1959). More recently exposures have been alleged after use of metal phosphides to control pests in adjacent buildings (Popp, 2002).
