Up to 12 million swarming bees forced a motorway to close in California after a lorry carrying crates of the insects overturned.
The California Highway Patrol says eight to 12 million bees escaped from the crates in which they were stored and swarmed over an area of Highway 99.
They stung officers, firefighters and tow truck drivers trying to clear the accident, reports Sky News.
The incident, near Sacramento, closed the road for a period.
Highway patrol officer Michael Bradley said a tractor trailer flipped over while entering the motorway on its way to Yakima, Washington.
The truck was carrying bee crates each filled with up to 30,000 bees. They had been used in the San Joaquin Valley to pollinate crops.
Officer Bradley said several beekeepers driving past the accident stopped to assist.