What type of foam would be inappropriate to use for oil spills?

In the context of responding to oil spills, using water-based foam is inappropriate because it lacks the necessary properties to effectively combat flammable liquid fires. Water-based foams are primarily designed for Class A materials, such as wood, paper, and textiles. When applied to oil spills, they can dilute the oil instead of forming a stable layer to extinguish the fire, which can lead to the spread of the oil and potentially exacerbate the problem.

In contrast, Class B foam, high-expansion foam, and protein foam are specifically formulated to form a blanket over flammable liquid surfaces, helping to suppress vapor production and prevent ignition. These foams are designed to encapsulate the oil, making them suitable for controlling spills and fires associated with hydrocarbons and other flammable liquids.