An estimated 250 million bees are on the loose in the US state of Washington after a lorry carrying beehives rolled over on Friday.

Authorities reported that a commercial lorry carrying 70,000 pounds of pollinator beehives overturned in the town of Lynden, five miles south of the border with Canada, allowing 250 million bees to make their escape.

“250 million bees are now loose,” the Whatcom county sheriff’s department posted on social media.

“AVOID THE AREA due to the potential of bee escape and swarming.”

More than two dozen beekeepers assisted emergency responders – some of whom were stung – with recapturing the bees, a spokesman for the sheriff’s department told local media.

The swarm of bees was so dense, it was “like a cloud”, Derek Condit, one of the beekeepers, told local media.

“It was pretty chaotic.”