Why did the powder monkies had to pick up the sacks of gunpowder barefoot?

Two hundred years ago young boys called ''powder monkeys'' ran below the decks of warships to pick up sacks of black gunpowder for the cannons above. It was ship law that this task must be done barefoot. Explain the proper Physics and the reasoning behind the law and why it might be the most important law in the ship?Why did the powder monkies had to pick up the sacks of gunpowder barefoot?
Shoes have nails.


Nailheads on th ebottoms of shoes striking other metal might spark.


one spark in a powder magazine = ship sinksWhy did the powder monkies had to pick up the sacks of gunpowder barefoot?
RT's answer may be right and sounds releasable, but some sources would need to be provided. I would say that almost no one on the ship wore shoes anyway because they didn't have traction and gun-powder was probably the most valuable thing on board so if they slipped and spilt the powder it would be rather nasty. Or maybe they boys didn't know how to keep their laces tied so they kept tripping... hey most people couldn't even read then.
because of the constant running,static would build up.the spark was enough to ignite the black powder,therefore no shoes.
Because, if they wore sandals that may create a fire hazard.