Hazardous Materials and Special Service Incidents
This section covers Hazardous Materials and Special Service Incidents: recognising hazards, zoning the scene and protecting people and the environment. The exam tests HAZCHEM and UN marking, hot/warm/cold zones, decontamination, CHEMET and water-reactive chemicals.
Recognition and zoning
- Approach from upwind, uphill and upstream; establish hot, warm and cold zones with an entry control point.
- Identify from placards, UN numbers, Tremcards, labels and site documents before committing.
- Use gas monitoring and the correct PPE; gas-tight suits only for trained wearers.
- Decontaminate before anyone leaves the warm zone; plan for mass decontamination.
- CHEMET models atmospheric dispersion; environmental protection uses booms, drains and absorbents.
Worked example
A white powder spills in a post room and one person feels unwell. The crew does not enter; it isolates the room, sets a cordon, confirms wind direction, requests specialist advice and establishes a decontamination area. The powder is identified before entry. Reasoning: an unknown powder may be toxic, corrosive or infectious; recognition and zoning prevent responders becoming casualties.
Traps
Entering the hot zone without PPE; skipping decontamination; using water on water-reactive substances; ignoring drains and run-off; relying on smell to identify a chemical.