A tanker truck carrying flammable material exploded, causing a huge fireball after hitting a stopped truck on a highway outside the northern Italian city of Bologna on Monday.
At least two people were killed and more than 60 injured, some with severe burns, during the midday accident.
A police video showed the tanker failing to slow down and plowing into the back of a truck that was stopped in traffic. Upon impact, the truck exploded in flames.
Another truck appeared to hit the tanker from behind. After an unspecified time lapse, during which the highway was cleared of most other vehicles, the truck erupted in a second explosion that spanned eight lanes of the highway and beyond.
The blast engulfed the area with flames and black smoke, and caused a bridge to partially collapse, the Italian fire service tweeted.
Firefighters have since extinguished the blaze, a spokesman said, adding that efforts were under way to determine the cause of the explosion and the exact number of victims.
A video published on Twitter by the fire service showed a huge column of black smoke billowing from the wreckage of the truck.
Authorities said the accident closed down a major interchange connecting highways linking northern Italy with the Adriatic coast, a popular destination as Italy heads into next week’s peak summer holiday travel period.