I'm still waiting to see when CNN and other news agencies correct their descriptions of the operation of the plant. The various news articles say that they are cracking ethane into ethylene plastic pellets, which description has at least one error and many missed steps. If they are creating polyethylene pellets from ethane gas, they would first convert ethane (C2H6) into ethene (or ethylene - the words are synonyms) (C2H4) by dehydrogenation - which is not cracking - and then convert to the polymer polyethylene (C2H4)n by polymerization - which is also not cracking. If they are bringing in heavier petrochemicals (propane, butane, etc) and converting those to ethylene, then that would be cracking.
I used to work at a company that sold instruments that were used all over those plants. Our company had made its reputation with vibration monitors (so a plant operator could know when a pump bearing was wearing out, for instance) but they provided other instruments for monitoring things like temperature and pressure, and general-purpose monitors (essentially digital voltmeters).