A man stands by a sink, lighter in hand. He holds it towards the tap. A fireball engulfs his arm.
It's this sort of set piece that brings to life documentarian Josh Fox's debut feature as he lays bare the water-polluting effects of hydraulic fracturing drilling, the method used by US energy firms in search of natural gas. His interviews are absorbing, but it's let down, if only slightly, by Fox's unfortunate monotone drone.