Containment and Confinement
Containment and confinement are the tactical heart of hazmat mitigation. Confinement keeps material where it is (diking, damming, plugging, patching, overpacking, covering, and vapor suppression); containment generally refers to keeping material from spreading further, often by collecting or transferring it. Technicians must know the standard tools and techniques: absorbents, booms, dikes, underflow dams, diversion, sealing leaks with plugs and patches, overpack drums, salvage covers, and foam blankets for vapor suppression. Understand when to act versus when to withdraw - if a container is failing, personnel safety and evacuation take priority over heroic patching.
Key concepts include product control versus vapor control, water-reactive material handling, flammable liquid foam application, and the importance of not creating new hazards (e.g., pushing product into a storm drain). Questions often test the choice between diking and damming, the purpose of an underflow dam, and when to use foam versus water. Traps: applying water to water-reactive materials; assuming a patch will hold under pressure; and forgetting to plan for runoff and disposal.
Rule of thumb: stop the source only if it can be done safely from a protected position; otherwise confine, evacuate, and let it burn or off-gas under control.
Worked example: A leaking drum of flammable liquid near a storm drain is best handled by diking around the drain and diverting flow, then overpacking the drum - not by flushing with water, which would spread the product.