heat only. Radiation can only come from a CRT monitor, about thirty years ago and that was negligible. Laptops are completely safe.
I have tried unsuccesfully to search for information about any dangers of operating a laptop on one's lap for long hours daily. Is there any danger? I know there is a lot of heat produced. Anything else entering my torso?

Chowhound
Comic Vine
GameFAQs
GameSpot
Giant Bomb
TechRepublic