Which tool poses the greatest threat as an ignition source at a vehicle accident with leaking gasoline?

The rotary saw poses the greatest threat as an ignition source at a vehicle accident with leaking gasoline due to its high-speed rotating blade and the ability to create sparks during operation. The saw is commonly used for cutting through structural components of a vehicle, but its metal blade can easily generate heat and sparks when it comes into contact with hard surfaces, including metal or concrete. If there is gasoline leaking from the vehicle's fuel system, the ignition of those vapors can occur when sparks are introduced.

In contrast, pneumatic lifting bags and hydraulic rescue kits are designed specifically for lifting and stabilizing vehicles without generating sparks, and while they can create pressure, they do not have exposed moving parts that could ignite flammable vapors. A chain come-along is a manual tool primarily used for pulling and does not typically generate significant heat or sparks, making it less of a concern in situations involving fuel leaks. Thus, recognizing which tools pose ignition risks is crucial in ensuring safety during rescue operations at vehicle accidents.