There have been many studies done on our long-term exposure to things like pesticides, radiation, and 3D TV, but in my opinion, one area that hasn't been taken seriously enough, is the negative health effects on the body from long-term exposure to lava.
Arguably, the best example of this comes from the people of Pompeii. There is mounting evidence that long-term exposure to lava can have a devastating impact on the lives of those affected by it.
The photo below is a startling one. Here a victim is seen trying to recline due to acute fatigue but is overwhelmed by pain from stiffening joints and muscles. Years of lava exposure literally turns them to stone. Scientists have named the condition "Michelangelo's Disease" while the locals refer to it as "Pompeii-ei-ei!".
An interesting side note, is that some people believe Pompeii's founder knew what was to come, the clue being the double exclamation marks at the end of the city's name. The fact that they're upside down remains a mystery (though, locals will tell you that the mistake was due to his hurried escape from lava flow).