Explosions at an oil depot near London on 11 December created one of Europe's biggest ever industrial fires. This image, taken by the Envisat satellite five hours after the initial blast, shows the resulting plume of smoke — it spans more than 140 km. Up to 270 million litres of fuel were held in the 20 tanks that exploded at the Buncefield site.

Credit: ESA

Atmospheric scientists flew a plane through the smoke on 12 and 13 December to log pollutants present and measure particle sizes. That should help to refine models for how smoke drifts after fires, volcanoes or nuclear blasts.

But the current plume poses little health or environmental hazard. The scale of the blaze is dwarfed by Kuwaiti oil wells set alight in 1991, when around 80 billion litres of oil burned.