When is a liquid waste, such as a caustic boiler cleaning liquid, considered pollution?

A liquid waste, such as caustic boiler cleaning liquid, is considered pollution primarily when it enters the environment. This is because pollution is defined as the introduction of harmful substances into natural surroundings, which can lead to adverse effects on ecosystems, human health, and the overall quality of the environment. Once a pollutant is released into air, water, or soil, it can cause significant harm, making the timing of its release crucial for identifying it as a pollutant.

While improper storage and mixing with other liquids can contribute to the risk of pollution or exacerbate the situation, these actions alone do not classify the liquid as pollution until it is released into the environment. Heating the liquid may change its properties or behavior but does not inherently define it as pollution. Thus, the focus is rightly on the point at which the waste interacts with the environment to determine its status as a pollutant.