No health effects have been noted at the background levels that people are exposed to on a daily basis.
High levels of exposure for short or long periods can cause headaches, lack of muscle coordination, dizziness, confusion, and changes in one’s sense of balance. Exposure of people to high levels of xylene for short periods can also cause irritation of the skin, eyes, nose, and throat; difficulty in breathing; problems with the lungs; delayed reaction time; memory difficulties; stomach discomfort; and possibly changes in the liver and kidneys. It can cause unconsciousness and even death at very high levels.
Both the International Agency for Research on Cancer (IARC) and the EPA have found that there is insufficient information to determine whether or not xylene is carcinogenic.