Source: http://www.popsci.com/science/articl...ficially-toxicBecause we don't spend a large chunk of time up there, we haven't done too much research on the long-term health effects of living on the moon. But a paper titled "Toxicity of Lunar Dust," covering several aspects of the effects of moon dust on the human body, offers some insight: the moon is basically trying to kill you.
Not actively, of course, but there are a lot of reasons to avoid the stuff (and no, a spacesuit isn't going to save you). The big problem is inhalation; even with a suit, dust can end up back in suit-free living spaces. Then the dust can travel inside travelers' lungs, causing inflammation and possibly, asbestos-style, even increasing the risk of developing cancer. The particles might be able to travel through the lungs more easily in the lower gravity environment, and exposure to UV and proton radiation could make the dust even more toxic.
But not to worry, there are still other ways it could hurt you. Without eroding the same way as soil on Earth, the rocky residue can be sharp, even occasionally coated in a glassy shell, causing skin irritation if you touch it. That's especially bad news for your eyes.
Researchers add a caveat for all this: it's only an approximation based on simulated dust particles, as they don't have samples that have been reliably kept in a lunar environment. But just in case, if you make a visit any time soon, exercise caution.