It must have been a driver's worst nightmare - cruising down the highway and suddenly running smack into millions of angry swarming bees.

The bees were on the loose in California after a truck in which they were being transported flipped on its side on the highway.

The California Highway Patrol said eight to 12 million of the honey bees escaped from the crates in which they were stored.

The truck was carrying over 400 beehives with 30,000 bees in each.

The bees stung police officers, fire crews, and tow truck drivers trying to corral them after the accident.

"People were being stung left and right. It was an ugly, ugly scene," one police officer said.

The great escape happened near Sacramento and the insects swarmed over an area of Highway 99.

For seven hours authorities brought in handlers who used smoke in a bid to calm the bees and coax them back into the hives.

Several beekeepers driving past the accident stopped to help the emergency services deal with the bees.

The highway had to be closed for a period.

Police did not know what caused the tractor trailer carrying the bees to flip over while entering the highway on its way to Yakima, Washington. But they said they believe the driver may have been driving too fast.

The bees had been used to pollinate crops in the San Joaquin Valley.

The honeybee is the world's premier pollinator and is invaluable to farmers for pollination.

But there has been a shortage of them in recent times because of "Colony Collapse Disorder". US beekeepers have been losing thousands of their bees, puzzling scientists. This has led to a rise in honey prices and has also threatened fruit and vegetable production.

After a seven-hour clean-up operation at Sacramento, police were unable to say how many bees remained unaccounted for. But they were not getting any calls from panicked drivers. "No news is good news," one officer said.

- March 28, 2008