Beekeeper Michael Barber woke up on Wednesday morning to several calls from police looking for help after five million bees fell off a truck in Canada.
The hives were being transported when the straps holding them in place came loose, allowing them to slip free.
Mr Barber said he arrived to "a pretty crazy cloud of bees" who were "very angry, confused and homeless".
Drivers were told to keep their windows up and pedestrians to stay away.
The scene in Burlington, Ontario was unlike anything Mr Barber has experienced in his 11-year career.
"It was something else," he told the BBC. "I hope to never experience it again."
Mr Barber, who owns Tri-City Bee Rescue in nearby Guelph, said he first received the calls from local police at around 07:00 local time (12:00 GMT), informing him that there was an accident that resulted in bee hives being spread all over the road.
At the same time police put out a public call on social media urging people to stay away from the area, which is about an hour south of Toronto.
The bees were in their hives packed up on the back of a truck and being transported to their wintering location when the accident happened.
As soon as Mr Barber heard from police, he put out a call to other beekeepers for additional help. About a dozen beekeepers eventually helped corral the insects.
Mr Barber said the bees and their hives were scattered over a 400-meter (1,300-foot) radius. On nearby cars and mail posts some of the younger bees were clustering, which he said they do when they are seeking safety.
"There were probably a thousand bees on the front of my truck," he said.
Other bees, ones that were angrier and older, were buzzing around.
After a few hours, most of the bees were able to find their hives, Mr Barber said, but a few hundred bees did not survive the accident.
Some beekeepers were also stung.
The driver of the truck was stung more than 100 times, Mr Barber said, as he wasn't wearing a full beekeeper suit. Paramedics were nearby and he was not seriously injured.
"There were a lot of flying bees that made even beekeepers in full suits nervous," he said.
He said he was grateful for the many local beekeepers that worked to keep the insects and the public safe, and added that the incident is a good reminder to always securely strap your bees.
"Lesson learned. Everybody survived and a few bees were hurt," he said. "Hopefully the hives will survive the winter."
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