Bell Canada had a major outage on July 17th 1999 when a tool was dropped on the bus bar for the main battery power that ignited the hydrogen from the batteries

Bell Canada had a major outage on July 17th 1999 when a tool was dropped on the bus bar for the main battery power that ignited the hydrogen from the batteries in one of the exchangeds in downtown Toronto. The fire department insisted that all power in the area be shut down which lead to the main switch that handled long distance call routing for all 1-800 numbers being offline for the better part of a day.