To die of exposure?
Answer:
Well, permit say a backpacker comes across a John Doe, out in the middle of nowhere, and the Coroner finds no signs of bombing or injury, or anything otherwise suspicious.
"Exposure" implies they probably died of any hypothermia, dehydration, or heatstroke.
Hypothermia.
family doctor's experience:
I reflect on it could be Hypothermia the temperature drops below the middle-of-the-road metabolism rate, so it could be because of many factor.
i think you can also be chitchat about skin cancer, from overexposure from UV street light (the sun), but this is rarely deep.
also, exposure to any deadly stimulus is to die of exposure, within brief
The question is too generaly defined. As written it could aim death of exposure to any noxious conditions: low temperature, radiation, toxic gas... everythig. So the answer to your question is:
"To die of exposure" routine that prolonged exposure to the mentioned agent is probably lethal.