Effects range from unsteadiness and tingling in fingers and toes to unconsciousness and death. Direct, prolonged contact with toluene liquid or vapor irritates the skin and the eyes. These effects are not likely to occur at levels of toluene that are normally found in the environment. Human health effects associated with breathing or otherwise consuming smaller amounts of toluene over long periods of time are not known. As a result, humans can develop problems with speech, hearing, and vision.
Humans can also experience loss of muscle control, loss of memory, and decreased mental ability.
Exposure to toluene can also adversely affect the kidneys. Laboratory animal studies and, in some cases, human exposure studies show that repeat exposure to large amounts of toluene during pregnancy can adversely affect the developing fetus. Other studies show that repeat exposure to large amounts of toluene adversely affects the nervous system, the kidneys, and the liver of animals. Toluene by itself is not likely to cause environmental harm at levels normally found in the environment. Toluene can contribute to the formation of photochemical smog when it reacts with other volatile organic carbon substances in air.