Which of the following is a safety hazard of a 12-volt storage battery?

A 12-volt storage battery poses significant safety hazards, particularly when it comes to handling its terminals. Shorting the terminals is a particularly dangerous action because it creates a direct path for current to flow between the positive and negative terminals. This can result in excessive current that generates heat, which can lead to burns or even ignite a fire if there are combustible materials nearby. Furthermore, the rapid heat increase can cause the battery to explode if it is a sealed type, resulting in acid spillage and harmful debris.

While touching both terminals with your hands can produce a potential for shock, the low voltage of 12 volts is generally not enough to cause severe electrical shock in most individuals. Regarding the concern about RF emissions and poison gas, while certain conditions could lead to the electrolyte producing gas, this is not a common direct hazard associated with basic handling of a standard 12-volt battery.

Overall, the primary and most immediate risk when dealing with a 12-volt storage battery is the potential for shorts and the hazards that arise from such situations, making that the most pertinent safety concern.