We examined videos from the 2008–2009 Gaza conflict, and from Fallujah, Iraq, where US forces had deployed against the Iraqi army in white phosphorus in 2004. Within a parametric model, we simulated projectiles detonating over various configurations of a generic urban environment. We concluded that in Gaza, white phosphorus was likely used to harass and terrorise citizens in order to clear neighbourhoods, rather than as a ‘smoke screen’, as the Israeli military had claimed. -FA