https://www.scientificamerican.com/article/what-is-ammonium-nitrate-the-chemical-that-exploded-in-beirut/

The Lebanese capital Beirut was rocked on Tuesday evening local time by an explosion that has killed at least 78 people and injured thousands more.

The country’s prime minister Hassan Diab said the blast was caused by around 2,700 tonnes of ammonium nitrate stored near the city’s cargo port. Video footage appears to show a fire burning nearby before the blast.