And to whom it may concern, microwave radiation is part of the same spectrum as visible light. It has a much lower wavelength, however, and any stray microwaves are caught by the oven and dissipate over time.

Also, you're thinking two different kinds of radiation. Microwave radiation is just energy passing through the air at a certain wavelength, one that water and fat molecules happen to be quite sensitive to.

The other kind of radiation is caused by atoms breaking apart of their own accord and shoting protons/electrons/whole atoms off at near light speed.

Hope that cleared things up.