It is not safe.
Try to clean out the dust that is blocking the laptop's intake and exhaust vents.
It could also mean the thermal paste used has more or less dried up and turned to powder. This actually happened to me once with the thermal paste that came with my Tuniq Tower (LGA 775). I believe they called it TX-1. Replacing the thermal paste more or less means you need to dismantle your laptop.
If you are scared to do so and your laptop is no longer under warranty (which I believe is the case), then you need to bring it to a repair shop and have them do it for you. I imagine this will be somewhat expensive though. While thermal paste is not very expensive, you need to pay someone to take apart the laptop apply the thermal paste...