The Indianapolis Star is reporting "[a] typo is to blame for the
water utility meltdown that led to a recent advisory for more than a
million residents in and around Indianapolis to boil tap water."
Officials say "a plant operator plugged the wrong value into a
computer, which sparked a series of events that ultimately lowered
water quality. They also acknowledged that no safeguards were in
effect to flag the mistake, which led the utility to issue a boil
advisory Jan. 6.
"The advisory ended the next day, but not before classes were
canceled for 40,000 students, hospitals and other businesses
switched to bottled water, and officials scrambled to ensure the
system contained enough water pressure to fight fires."
The employee was fired and some input validation (gasp!) was put in
place.