Which of the following would be a potential ignition source in an explosive atmosphere?

An operating radio can create sparks or generate heat, which are potential ignition sources in an explosive atmosphere. Radios emit electromagnetic radiation and can create electrical arcs when buttons are pressed or when they are turned on or off. In environments with flammable gases, vapors, or dust, even a small spark could ignite an explosion.

While other activities listed, such as using bells or whistles, touching metal surfaces, or donning and doffing SCBA, might have associated risks, they are generally less likely to produce a direct ignition source compared to the electrical operations of a radio. It’s critical to understand that in hazardous environments, any device that creates a spark or heat must be approached with caution, making the operation of radios particularly risky in explosive atmospheres.