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CSB Investigation Report No. 2017-04-I-MO 2017 Safety Safety
Loy-Lange Box Steam System Pressure Vessel (Boiler-like) Oxygen Pitting Rupture
Loy-Lange Box Company, St. Louis, Missouri
Related equipment → Boiler (boiler)
4Fatalities
1Injuries
Corrosive ruptureMechanism code STD
⌗Failure Mode · ISO 14224 Mapping
Damage mechanism (recorded in KB)
Corrosive ruptureSTD
ISO functional code (as recorded)
ISO 14224:2016 functional failure code
STD · Structural failure
ISO STD — Structural failure.
1What Happened

Steam generation system semi-closed receiver (SCR) oxygen pitting + general corrosion thinning -> catastrophic rupture -> BLEVE

2Root Cause

Oxygen pitting + general corrosion thinning + poor 2012 repair (left damaged material) + inspection gap -> pressure vessel rupture

3Reliability Lessons (from investigation root cause)
  • Oxygen pitting
  • general corrosion thinning
  • poor 2012 repair (left damaged material)
  • inspection gap -> pressure vessel rupture
4Associated Failure Mechanisms (Keywords)
boiler pressure vessel oxygen corrosion pitting thinning rupture steam system drum
About the Failure-Mode Code (click to expand)

The recorded code STD is an ISO 14224:2016 functional failure code (describes what the equipment failed to do). The damage mechanism (how it failed) is shown in the Mapping block above. The two are distinct dimensions in ISO 14224.

5Evidence Source (transparent)
Authority：U.S. Chemical Safety and Hazard Investigation Board (CSB)
Official Report：www.csb.gov ↗
Data Verification：verified_url_csb_report_2026-07-20
↗Related Failure Modes · Traceability
Steam Drum Internal Corrosion fmSteam Separator Failure -> Wet-steam Carryover fm_2Relief Valve Set-pressure Drift fm_3Valve Seat Leak fm_4Furnace Tube Rupture tube_ruptureInternal Fouling -> Overheating fm_5Superheater Tube Rupture fm_6High-temperature Oxidation / Creep fm_7Dew-point Corrosion Perforation fm_8Burner-tip Coking / Blockage fm_9Ignition Failure / Flameout fm_10Cavitation fm_11Mechanical Seal Leak fm_12Insufficient Deaeration -> Oxygen Corrosion fm_13
Report No. 2017-04-I-MO · Data from CSB public investigation conclusions, compiled by Reliability AI, for reliability demonstration purposes only. This case is derived from public incident investigation reports for learning purposes only. AIM does not endorse or guarantee its accuracy.