How long should personnel wait to enter the discharge site after a fireworks display?

The most suitable answer is that personnel should wait for a period determined by the operator before entering the discharge site after a fireworks display. This reflects the principle that the responsible individual overseeing the fireworks operation must assess specific conditions on-site, including residual hazards such as undetonated shells, smoke, and potential fire risks.

The operator's judgment is vital because they are trained to evaluate the situation accurately and can make an informed decision that ensures safety. This flexibility allows for variations in wait times based on the type of fireworks used, environmental conditions, and the specific layout of the discharge area, all of which can significantly influence the safe re-entry timing.

Choosing an arbitrary time frame, such as 30 minutes or waiting until all spectators have left, may not always provide adequate safety, as immediate environmental conditions might dictate a longer wait. Thus, deferring to the operator ensures that personnel only enter the area when it is deemed safe.