Which of the following is a sign of a possible chlorine leak?

A whistling sound is indeed a sign of a possible chlorine leak. When chlorine gas escapes from its containment, it can create a high-pressure release that produces a whistling or hissing sound as it exits. This occurs due to the rapid expansion and turbulence of the gas, which can indicate a rupture or other failure in the system.

While other signs may indicate different types of issues, the distinct whistling noise is more commonly associated with a gas leak, especially in the case of chlorine, which is known for its characteristic odor as well. Recognizing these sounds prompt immediate action to address potential hazards before any serious exposure occurs. It's essential for individuals working in environments where chlorine is present to be aware of such auditory signals as part of their safety protocols.