What term means the placement of material to form a barrier that keeps a hazardous material from entering an unwanted area?

The correct answer is the term "Diking." This term specifically refers to the practice of creating a barrier, often using soil, sandbags, or other materials, to contain and prevent the spread of hazardous substances. Diking is a critical technique in hazardous materials response, as it helps to confine materials to a designated area, thereby minimizing the risk of contamination in surrounding locations and protecting both human health and the environment.

Diking is particularly effective for liquids, where the creation of a physical barrier ensures that fluids do not migrate outside a certain perimeter. This strategy can be particularly vital during spills or leaks, as it allows emergency responders to manage and control the situation more effectively while preparations for cleanup or evacuation take place.

Other terms listed, while related, do not specifically describe the action of setting up a physical barrier in the same way. For instance, "Containment" broadly refers to any action taken to control the spread of hazardous materials but does not imply a physical barrier is being set up. "Isolation" pertains to separating a hazardous area from people or the environment, but again does not involve the creation of a physical barrier. Lastly, "Blockading" is sometimes used in different contexts, but it does not have the specific connotation related