What happened

A fuel tanker exploded at the Islam Qala border crossing with Iran while customs employees were reportedly inspecting a gas tanker, triggering a chain-reaction fire that engulfed more than 500 trucks carrying fuel and natural gas. Two explosions were powerful enough to be detected by NASA satellites. At least 20 people were injured; Afghan first responders lacked the means to extinguish the blaze and requested Iranian firefighting aircraft. The fire forced Afghanistan to shut off its electricity imports from Iran, leaving Herat without power. The precise cause was not established in the cited reporting.

When cited sources give different casualty, damage or spill figures for this event, they’re reported side by side above rather than merged into one number. See how confidence levels work.