Microwave ovens pulse electromagnetic waves through food, exciting the molecules and causing them to move, vibrate and heat up as they respond to the microwave radiation.
It is a device called a Magnetron in the microwave oven that produces wave energy
The main routes of exposure to naphthalene are inhalation and skin contact. Once inside your body this chemical breaks down and effects the liver, lungs and kidneys. Common symptoms of exposure are dizziness, headache and nausea.