Hacker attempted to poison water supply of Florida city, officials say

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Local and federal authorities are investigating how a hacker was able to remotely gain access to a Florida city’s water treatment plant in an unsuccessful attempt at what could have amounted to a mass poisoning.

A mysterious hacker infiltrated a computer for the water treatment system of the city of Oldsmar, near Tampa, and briefly increased the amount of sodium hydroxide, also known as lye, by a factor of more than 100, the Pinellas county sheriff, Bob Gualtieri, said on Monday.

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The chemical is used in small amounts to control the acidity of water but it is also a corrosive compound commonly found in household cleaning supplies such as liquid drain cleaners. In large quantities it can cause irritation, burns and other complications.

A sharp-eyed supervisor noticed the measurements of the chemical suddenly changing wildly on his computer screen and promptly stepped in to reverse the action, leaving the city’s water supply unaffected, the Tampa Bay Times reported.

Chris Hayes
(@chrislhayes)

This is honestly one of the most upsetting things I’ve seen. An attentive civil servant saved the town from…mass poisoning. https://t.co/aufA0oEtnr

February 8, 2021

The hack occurred on Friday and the unknown suspect was able to breach Oldsmar’s computer system and briefly increased the amount of sodium hydroxide from 100 parts per million to 11,100 parts per million, Gualtieri said.

“At no time was there a significant adverse effect on the water being treated,” Gualtieri said, adding: “Importantly, the public was never in danger.”

A plant worker first noticed the unusual activity at around 8am on Friday when someone briefly accessed the system. At about 1.30pm, someone accessed it again, took control of the mouse, directed it to the software that controls water treatment and increased the amount of sodium hydroxide.

Officials said other safeguards in place probably would have caught the change before it reached the water supply. The remote-access system the hacker was able to use has since been disabled.

The treatment plant that was targeted provides water to businesses and about 15,000 residents, Gualtieri said.

The sheriff’s office, the FBI and the Secret Service are investigating.

Nobody has been arrested, though investigators have some leads. Other area municipalities have been alerted to the attack.