Local and federal authorities are investigating after an attempt on Friday to poison the water supply in the city of Oldsmar, said Pinellas County Sheriff Bob Gualtieri.
Someone remotely accessed a computer for the city’s water treatment system and briefly increased the amount of sodium hydroxide, also known as lye, by a factor of more than 100, Gualtieri told a news conference on Monday. 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 products, such as liquid drain cleaners.
The city’s water supply was not affected. A supervisor working remotely saw the concentration change on his computer screen and immediately reversed it, said Gualtieri. City officials emphasized on Monday that several other safeguards are in place to prevent contaminated water from entering the water supply and said they had disabled the remote access system used in the attack.
The Pinellas County Sheriff’s Office is investigating, along with the FBI and Secret Service, said Gualtieri.
No one was arrested, said Gualtieri, although investigators have some clues. They don’t know why Oldsmar was the target, he said. He added that other municipalities in the area were warned of the attack and encouraged to inspect the safeguards for their water treatment systems and other infrastructure.
Although some cities obtain water through Pinellas County, Oldsmar provides water directly to its businesses and some 15,000 residents, said Gualtieri. The computer system at the water treatment plant has been configured to allow authorized users to access remotely for troubleshooting purposes.
A plant operator was monitoring the system at about 8 am on Friday morning and noticed that someone accessed it briefly. He didn’t find this unusual, said Gualtieri, because his supervisor accessed the system remotely regularly.
But around 1:30 pm the same day, said Gualtieri, someone accessed the system again. This time, he said, the operator watched someone take control of the mouse, direct it to the software that controls the water treatment, work inside it for three to five minutes, and increase the amount of sodium hydroxide from 100 parts per million to 11,100 parts per million.
The attacker exited the system, said Gualtieri, and the operator immediately changed the concentration back to 100 parts per million.
“There was never a significant adverse effect on the treated water at any time,” said the sheriff. “It is important to note that the public was never in danger.”
Even if the operator had not caught it, he said, it would take more than a day for the water to enter the water supply.
“The protocols that we have in place, monitoring protocols, they work – that’s the good news,” said Oldsmar Mayor Eric Seidel. “Even if they had not been detected, there are redundancies in the system that would have detected the change in the pH level.
“The important thing is to warn everyone,” he said. “There is a bad actor out there.”
Senator Marco Rubio also addressed the attack in a tweet on Monday, saying that “it should be treated as a matter of national security”.
The Sheriff’s Office learned of the attack and started investigating Friday night, said Gualtieri. Investigators still do not know whether the attack originated in or outside Pinellas County, Florida or the United States. If the attacker is arrested, he said, they will face state and possibly federal criminal charges.
Contact with sodium hydroxide can kill the skin and cause hair loss, according to the National Center for Biotechnology Information. Ingestion can be fatal.
Gualtieri said he did not know what physiological effects would result from the increased concentration in the attack. Nor was it immediately apparent whether a similar attack had already taken place in the United States. In 2007, water in a city in Massachusetts was accidentally treated with a lot of caustic soda, causing burns and skin irritation among people who showered with it.
“I’m not a chemist,” said Gualtieri. “But I can tell you what I know is … if you put that amount of this substance in drinking water, it is not a good thing.”