Ammonium nitrate fertilizer powered a blast that killed more than 100 people and injured more than 4,000 in Beirut, Lebanon.
It was owned by Russians who abandoned a shipload of the fertilizer in 2013. It was stored in a warehouse at the port which has been heavily damaged.
Grain in elevators nearby is no longer fit to eat, including imported wheat.
It will cost billions and take years to rebuild the damaged port and nearby buildings, including residences.
Hospitals were overwhelmed with injured people, many of them hit by shattering glass. Some reported damage to homes as far as six kilometres from the site.