What does "hazardous materials incident" refer to?

A "hazardous materials incident" refers to a situation where hazardous materials are released into the environment, posing a risk to human health, safety, and the environment. This can occur through various means, such as spills, leaks, or accidents involving the handling, storage, or transportation of these materials. The definition emphasizes the concern for safety and the potential impact of this release, which necessitates immediate response measures to mitigate harm.

In contrast, minor leaks of non-toxic substances do not fit the definition of a hazardous materials incident, as they lack the dangerous characteristics that classify substances as hazardous. A transportation issue without material release does not qualify as an incident if there is no actual release of hazardous materials. Similarly, an emergency drill, while important for training and preparedness, is not an incident unless it involves a real release or situation that endangers health or the environment. Thus, the focus on actual releases in the definition is what makes the first choice the correct answer.