IAQ UK is an independent organisation with the aim of 'raising the agenda of indoor air quality within the home and workplace'

IAQUK Resources - Toluene

Sources of Pollution

Toluene is a very important chemical worldwide and many millions of tons of Toluene are made globally each year.  Typical used as a solvent for paints, coatings, rubber, resins and oils   Toluene is used in the production of plastics and medicines and can also be found in tobacco smoke.  It has also been used in the process of removing the cocaine from coca leaves in the production of Coca-Cola syrup.


Toluene is used to manufacture polymers that are used to make nylon, plastic soda bottles, and polyurethanes and for pharmaceuticals, dyes and cosmetic products.


Consumers may find Toluene in products such as adhesives, cleaners, floor polish, hard surface cleaners, paints, inks, paint cleaners, paint and varnish removers and thinners, coatings, particleboard, leather dressings, lubricating oils, fingernail enamels and removers, shoe polish and cleaners, silicone sealants, printing ink, varnishes, lacquers, leather tanning, metal cleaners, solvent-thinned products (exterior stains, primers, interiorstains, clear finish), colouring pens and markers, wood office furniture and vinyl flooring.


Toluene can be used as an octane booster in petrol used in internal combustion engines. An internal combustion engine is where the combustion of a fuel occurs with air, which improves performance capacity of vehicles, particularly used in Formula 1.


You are most likely to be exposed to Toluene if you work in industries where it is used extensively, for example, engineering, footwear, construction, textiles, chemicals, printing, woodworking, rubber and dry cleaning.


Health effects

Toluene is not water soluble, of an absorbed dose of toluene, 25%-40%, is exhaled unchanged via the lungs, a greater proportion is metabolized and excreted via other pathways. Hippuric acid has been used as an indicator of toluene exposure in the urine, but has not been seen as reliable, due the body’s ability to create without exposure.  A very small percentage of the toluene is metabolized to cresol. Thus, the presence of o-cresol in the urine, a constituent not normally found in the human urine, can be used as a confirmatory test for toluene exposure.

Some toluene is stored in the human body fat and is eliminated from the fat, with a half-life of 1-3 days after exposure has ceased. Short-term exposure levels, mainly affect the central nervous system (the brain), causing headaches, tiredness, confusion, nausea, dizziness, clumsiness, drowsiness, and other effects like those of drunkenness. The symptoms of short-term over-exposure usually clear up within hours of exposure stopping but, as with drinking alcohol, these symptoms can increase your chances of having an accident.  Direct, prolonged contact with vapour can irritate the eyes, and cause dry skin and skin rashes.


Long-term exposures to high levels can affect the kidneys, nervous system, liver, brain, and heart have been linked to permanent brain damage. Also reported are problems with speech, vision and hearing, loss of muscle control, loss of memory and balance and reduced scores on psychological tests. If you are pregnant, repeated exposure to toluene may increase the risk of damage to the fetus.


In extreme cases, unconsciousness and death can result from exposure to very high concentrations of Toluene vapours. Generally speaking, the greater the exposure, the more severe the symptoms. Because the body can eliminate Toluene quickly from the body, occupational health tests must be conducted quickly after exposure to identify the day’s exposure.   Toluene can be measured in the blood, and the blood level used as an approximate gauge of the airborne concentration.  Blood is typically drawn at the end of a work shift, however, blood levels decline very rapidly after exposure stops, with an initial half-life of 2-3 hours.  If a severe exposure has occurred, blood and urine analyses and other tests may show whether the brain, heart, or kidneys have been affected.


Employers should introduce measures to prevent exposure to Toluene or, if this is not possible, to ensure that exposure is controlled. They should provide appropriate ventilation and protective equipment (gloves, respiratory equipment, goggles, apron etc). Special precautions are required if the work is in a confined space. Employers should also monitor workers’ exposure and provide appropriate training with this solvent.

Technical - Tetrachloroethylenee - C7H8

  • Mono-substituted benzene derivative using CH3
  • Clear, colourless, flammable, water insoluble liquid
  • Sweet, pungent odour
  • CAS Number: 108-88-3
  • LTEL - 50ppm (191 mg/m³)
  • STEL - 150ppm (574 mg/m³)
  • Risk Phrases: R11, 20, 48, 63, 67
  • Safety Phrases: S16. 25. 29, 33

Toluene (also known as Methylbenzene; Toluol; Pphenylmethane; Methylbenzol; Methyl-benzene; Monomethylbenzene).


Toluene, formerly known as Toluol, is a clear, colourless, flammable, water-insoluble liquid, although soluble in most organic solvents, with a sweet, pungent odour.

Toluene occurs naturally in crude oil and is made during the process of refining oil into petrol and other products. Chemically, it is a mono-substituted benzene derivative, i.e. one in which a single hydrogen atom from the benzene molecule has been replaced by a univalent group, in this case from a methyl group. It is an aromatic hydrocarbon (hydrocarbon is an organic compound of hydrogen and carbon) (aromatic means a sweet smell), and has a variety of uses. The name Toluene was derived from the older name toluol, which refers to tolu balsam, an aromatic extract from the tropical Colombian tree Myroxylon balsamum, from which it was first isolated. It was originally named by Swedish chemist Jöns Jakob Berzelius.  Berzelius was known for introducing the system of chemical notation in which elements were given simple written labels—such as O for oxygen, with proportions noted by numbers. This is the same basic system used today, the only difference being that instead of the subscript number used today (e.g., H2O), Berzelius used a superscript (H2O).