Toluene is a clear colourless liquid with a distinctive odouralso known as an aromatic hydrocarbon. It occurs naturally in crude oil and in the tolu tree, and can be produced in the process of making gasoline. Toluene is insoluble in water and its vapours are heavier than air. It is a methylbenzene and is the simplest member of the class toluenes. [1,2]
Toluene is used in many different applications, including aviation, as a solvent and as an industrial feedstock. For airplanes and cars, toluene is used as an octane booster in fuel. It is also used as a solvent in paints, nail polish, adhesives, permanent markers and certain types of glue. It is also sometimes used in leather and printing processes and as a recreational inhalant.
Routes of Exposure 
The most common route of exposure for toluene in the ambient air is in automobile emissions.
- Common household products, such as paints, nail polish and adhesives are the highest source of toluene in indoor air.
- Cigarette smoke is also a source of toluene.
- Levels of toluene are highest in indoor areas, followed by urban areas and then rural.
- People can be exposed to formaldehyde by skin contact, inhalation, by eye contact, or by ingestion.
Toluene poisoning can affect a range of systems, including the nervous, respiratory and cardiovascular systems.
Acute Effects 
Severity of symptoms depends on the level and type of exposure.
- The Central Nervous System (CNS) is the primary target organ for toluene exposure.
- Other acute effects include: narcosis, CNS dysfunction, fatigue, sleepiness, headache and nausea.
- Inhalation of toluene has a low chemical toxicity.
- Ingestion of toluene can lead to a swollen liver, depression of the CNS, congestion and hemorrhage of the lungs and necrosis of myocardial fibres.
- Acute exposure to it may cause cardiac arrhythmia.
Chronic Effects 
Toluene is toxic to multiple body systems. Long-term exposure to the liquid can cause neurological damage, including CNS depression, ataxia, cerebral atrophy, nystagmus and neurobehavioural effects. It can also result in respiratory difficulties, such as irritation of the respiratory tract, a sore throat, headaches, and inflammation and degeneration of the nasal and respiratory epithelium. Pregnant women who are exposed to toluene could see developmental delays, CNS dysfunction, minor limb abnormalities and attention deficits in their children. Additionally, children who were born to toluene abusers have been known to show temporary renal tubular acidosis.
~h2First Aid Measures 
- Ingestion: If ingested, rinse mouth and DO NOT induce vomiting. Immediately call a doctor or a poison centre. In victim vomits while lying on their back, put them in a recovery position.
- Skin contact: In case of skin or hair contact, shower/wash immediately for at least 15 minutes with water. Remove all contaminated clothing and shoes while washing. Wash contaminated clothing before re-wear. Consult doctor.
- Eye contact: Flush eyes carefully with water for 15 minutes. Do not forget to wash underneath the eyelids. Call a doctor immediately.
- Inhaled: Take contaminated person to nearest fresh air source and monitor their breathing. If they are not breathing, perform CPR. If victim is struggling to breathe, they can be given oxygen.
Exposure Controls/Personal Protection 
Engineering controls: Safety showers and emergency eyewash fountains should be accessible in the immediate area of the potential exposure. Ensure there is adequate ventilation. Use toluene with local exhaust ventilation. Whenever possible, material should be handled in a laboratory.
- Personal protection: Safety glasses, solvent-protective apron, safety glasses with side shields and solvent-protective gloves.
The Occupational Safety and Health Administration (OSHA) has set an 8-hour time-weighted average (TWA) concentration for toluene of 200ppm, with an acceptable ceiling concentration of 300ppm.
Safe Work Australia: Safe Work Australia has set an 8-hour TWA concentration for toluene of 50ppm, and a short-term exposure limitusually 15 minutesof 150ppm.