What is a critical safety aspect regarding the operation of flame effects?

Ensuring that only trained personnel operate flame effects is critical for safety due to the inherent risks associated with handling flammable materials and equipment. Trained personnel understand the necessary safety protocols, equipment operation procedures, and emergency procedures required to manage potential hazards effectively. Their expertise helps to minimize accidents and ensure that flame effects are performed safely, maintaining a protective environment for both the audience and the performers.

The other options, while relevant to the larger context of flame effects in entertainment, do not directly address safety concerns. The types of fuels used are indeed important, but if untrained personnel are handling them, the risks remain significant. Minimizing costs can compromise safety if cheaper, less safe options are chosen. Similarly, while audience entertainment value is a factor in designing a performance, it should never overshadow the paramount importance of operating flame effects safely and responsibly.