Toxic hives?

An interesting quote from Pennsylvanian beekeeper Dave Hackenberg who has lost an estimated one-third of his 3,000 colonies to the mysterious so-called Colony Collapse Disorder:

“They disappeared. They left and never came back. There were no dead bees on the ground, just empty boxes. Nothing went near the hives. They sat there empty, like there was something toxic, and it was repelling everything.”