At a hazardous materials incident, firefighters can operate in several strategic modes depending on the situation, resources, and risk to responders and the public. The offensive mode involves aggressive actions to stop the release at its source, such as plugging, patching, or shutting down a valve. This mode requires specialized training, equipment, and a high level of risk acceptance. The defensive mode focuses on protecting people, property, and the environment without attempting to stop the release, using actions such as diking, damming, diversion, and evacuation. The nonintervention mode is used when conditions are too dangerous; responders isolate the area, deny entry, and allow the product to burn or disperse naturally. A transition mode may be used as conditions improve, allowing operations to shift from defensive to offensive. Selecting the correct strategy is critical to maintaining responder safety and controlling the incident effectively.