Elior Doani On Friday, February 5, a hacker breached the computers at the water treatment plant for Oldsmar, Florida, and tried to poison the city’s 15,000 inhabitants by dumping a large amount of sodium hydroxide – commonly used to unblock drains – into its drinking supply. Fortunately, the duty operator noticed his mouse was moving around the screen, clicking on commands that controlled the chemicals in the water. At first, he assumed it was a supervisor using remote access to troubleshoot a problem. Then he noticed it had increased the sodium hydroxide level from about 100 parts per million to 11,100 parts per million. As soon as the hacker released control a couple of minutes later, the operator reversed the command and alerted his superiors.