The accident happened in northwestern Washington state, close to the Canadian border near Lynden, the Whatcom County Sheriff's Office said in social media posts.

About 250 million bees are estimated to have escaped from the truck.

"250 million bees are now loose," wrote Whatcom County Sheriff on its social media page. "AVOID THE AREA due to the potential of bee escaping and swarming."

Goal to save as many bees as possible

Roads in the region have been closed as bee experts help with the clean-up.

"Thank you to the wonderful community of beekeepers: over two dozen showed up to help ensure the rescue of millions of pollinating honey bees would be as successful as possible," according to the sheriff's office.

The plan is to allow the bees to return to their hives and find their queen bee in the next day or two, it added.

The goal is to save as many of the bees as possible.

What role do they play in food production?
 

Honeybees play a key role in pollination and food production.

They pollinate over 100 crops, including nuts, vegetables, berries, citrus and melons.

Bees and other pollinators have been facing numerous threats and declining for years.

Experts blame insecticides, parasites, disease, climate change and lack of a diverse food supply for their decline, which could have major implications for agriculture and food security.