OTHWelding (hot work) atop storage tanks without isolation or combustible-gas testing; hydrocarbon vapor in tank ignited and exploded
Welding above an uncleaned, unisolated crude-oil tank without combustible-gas testing ignited hydrocarbon vapor — 3 contract workers standing on tanks killed, 1 seriously injured
The recorded code OTH 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.
bottom_plate_perforationBottom Weld Crack bottom_weld_crackUnder-deposit Corrosion under_deposit_corrosionShell Thinning shell_thinningWeld Crack weld_crackCorrosion Under Insulation (CUI) cuiRoof Corrosion roof_corrosionFloating Roof Sticking floating_roof_stickingSeal Leak -> VOC Emission seal_leakDifferential Settlement differential_settlementConcrete Crack concrete_crackPad Failure pad_failureFreezing/Sticking freezing_stickingSeat Corrosion seat_corrosionElement Plugging element_pluggingElement Corrosion element_corrosionN2 Supply Loss n2_supply_lossControl Valve Failure control_valve_failureAntenna Fouling antenna_foulingElectronics Failure electronics_failureWire Sticking wire_stickingDisplacer Perforation displacer_perforationContact Corrosion contact_corrosionFloat Sticking float_sticking