Lebanese officials attributed Tuesday’s cataclysmic explosion in Beirut to multiple metric tons of ammonium nitrate stored in an unsecured warehouse. Prime Minister Hassan Diab said that 2,750 metric tons of the chemical, predominantly used as an agricultural fertilizer, had detonated in the city’s port, but the source of ignition was still unclear. The country’s interior minister and security chief said the same. The country’s Supreme Defense Council declared a state of emergency in response to the blast. The country’s president, Michael Aoun, said such storage of explosive materials was “unacceptable.” The blast killed more than 70 people and injured over 4,000.