Cargo Hazards and Safety Culture on Tankers
This domain examines the hazards created by oil, chemical and gas cargoes and the safety culture that controls them. The exam expects you to recognise hazard types and explain how reporting, permits and human factors prevent incidents.
Cargo hazards
Flammability is described by flashpoint, flammable range and vapour density. Toxicity includes acute exposure to hydrogen sulphide, benzene and carbon monoxide. Reactivity covers cargo-to-cargo, cargo-to-water and cargo-to-tank reactions. Other hazards are pressure, cryogenic cold, oxygen deficiency and static electricity.
Safety culture
A working safety culture combines a just culture, near-miss reporting, permit-to-work, toolbox talks, Stop Work Authority and the safety management system. Human factors such as complacency, fatigue and normalisation of deviance are recognised as root causes. The aim is to report problems before they become spills or injuries.
Worked example
An enclosed tank reads 19.5% oxygen, 0% LFL hydrocarbon and 2 ppm hydrogen sulphide. Do you enter? No. The oxygen level is below the required 20.9% by volume, so the space is not safe for entry even though hydrocarbon and H2S readings appear acceptable. Ventilate, isolate and retest the atmosphere before entry, and use a permit with a standby man.
Traps that cost marks
Treating a lack of smell as proof of safety; reversing LFL and UEL; assuming ventilation makes a tank safe without retesting; thinking PPE replaces atmosphere testing; confusing a near miss with an accident.