When responding to an incident in which explosive materials are suspected, is it safe to use wireless communication devices?

No

Explanation:

Wireless communication devices like the cell phones transmits signals using radio or electromagnetic wave, which would trigger a bomb. An example of this kind of bomb is the home-made bomb also known as IED (improved explosive device).

The most common type of this IED is the radio controlled IED, which uses electromagnetic wave from a cell phone or a radio controlled type firing circuit. Insurgents, criminals etc, make use of such devices, since the materials are easy to get and are affordable.