This is a Monday challenge: Can anyone explain the origin and rationale of the universal safety regulation that requires people on construction sites the world over to wear hard hats?

On Friday, a paving crew from Knife River, under contract with the city of Albany, spent a day on Sixth Avenue outside the Democrat-Herald repaving the trench that previously had been dug for a new water line. More than a dozen workers were on the scene, all of them sporting the requisite helmet.

They were working in the open under a blue sky. Other than the atmosphere, there was nothing between their heads and the outer edges of the universe - if it has outer edges.

There was nothing up there that could have fallen on their heads. They were perfectly safe from any overhead threats - unless it was the sunshine. But it's hard to believe that hard hats are required to ward off sunburn.

So what's the rationale? (hh)