Yikes! Brings new meaning to the phrase "working without a net".
Ha. Tell that to the folks at the Colonial pipeline or that hospital that got hacked with ransomware.
Don't get me started. Never mind, here goes.
I used to work for the LA County Office of Emergency Management. My notorious background included building data acquisition and control systems for TRW Defense and Space Systems Group and a couple of other employers along the way.
20 years ago, I did some [off the record] consulting for the Terrorism Early Warning Group of the Sheriff's department told them that a cyber attack could cause as much damage as a mad bomber. After 9/11 the focus was on physical buildings, etc. plus disasters, but cyber attacks were never rehearsed in exercises (still hadn't at the time I retired). Up until the day I retired in February, I said that a cyber attack would not be the basic data breach and theft of credit and banking info, but would be a series of industrial accidents caused by computer "failures". Since many (thank goodness not all) decision makers don't fully understand computer control systems, they don't focus on them. Instead, the control systems were tied into company networks for convenience, but that introduced a vulnerability from hacks or ransomware since the control systems go down with the rest of the network. While I can't say for sure that the Colonial and Hospital situations were tied into the main networks (and the Internet), it certainly looks that way.
I've been a proponent of isolation of critical control systems, but that means numerous site visits to maintain the systems. It makes maintaining these systems much less convenient, trickier to keep consistent (you have to maintain a tight maintenance schedule) and more costly, but it keeps them away from anything but the idiot who picks up a USB stick in the parking lot and puts it in one of the control computers.
They sent us to a Cybersecurity Training and during introductions I literally dictated the scenario of the training they were about to give. Sometimes, being the OLD GUY pays off.
Bottom line -- isolate your control systems from the Internet and the company's main network. There are ways.