On March 15, 1994, an accidental fire occurred in a Pacific Bell telephone exchange, interrupting telephone service for a large part of the city of Los Angeles. Some areas of the city were without E911 service for more than 12 hours. The fire occurred during the rearrangement of battery strings on a power plant that supported telecommunications equipment carrying E911 traffic. Investigators determined that a shutdown of rectifiers in the power plant began a sequence of events that caused a short in temporary transition cables.
This fire highlighted the absence of universally accepted fire protection systems for telecommunications facilities, as well as potential risks and difficulties firefighters can face when suppressing fires in these properties.