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

IAQUK Resources - Xylene

Sources of Pollution


Approximately 70% of mixed Xylene is used in the production of Ethyl Benzene and the m-, o-, and p-isomers. The remaining mixed Xylene is used as a solvent, in products such as paints and coatings, or blended into petrol. Xylene is often used as a solvent and in the printing, rubber, and leather industries.


It is used as a cleaning agent for steel and for silicon wafers and chips.


It is used as a thinner for paint, and in paints and varnishes. It may be substituted forToluene to thin lacquers where slower drying is desired.


The Xylene isomers are used primarily for internal industrial operations as solvents and intermediates in synthetic reactions.


m-Xylene is a chemical intermediate in the production of isophthalic acid and isophthalonitrile; isophthalic acid, in turn, is used in the manufacture of polyesters.


o-Xylene is a chemical intermediate in the synthesis of phthalic anhydride (forplasticizers), phthalonitrile, 4,4-(trifluoro-1-(trifluoromethyl) ethylidene) diphthalic anhydride (for polyimide polymers), o-toluic acid, vitamins, and pharmaceuticals.


p-Xylene is a chemical intermediate for the synthesis of dimethyl terephthalate, terephthalic acid (for polyesters), dimethyl tetrachloroterephthalate, vitamins, and pharmaceuticals. It is used for the manufacturer of plastic bottles and polyester clothing.   98% of p-Xylene production, and half of all xylene, is used for polymer production.


Both o-xylene and p-xylene are used as components of insecticides.


Health effects

Xylene exhibits neurological effects. High levels from exposure for acute (14 days or less) or chronic periods (more than 1 year) can cause headaches, lack of muscle coordination, dizziness, confusion, and alterations in body 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 and other problems with the lungs, delayed reaction time, memory difficulties, stomach discomfort, and possibly adverse effects on the liver and kidneys. It can cause unconsciousness and even death at very high levels.


Xylene or products containing Xylene should not be used indoors or around food. Xylene is not a controlled substance.


It is not yet known whether Xylene harms the unborn fetus if the mother is exposed to low levels of Xylene during pregnancy.


Laboratory tests can detect Xylene or its breakdown products in exhaled air, blood, or urine. There is a high degree of agreement between the levels of exposure to Xylene and the levels of Xylene breakdown products in the urine. However, a urine sample must be provided very soon after exposure ends because xylene quickly leaves the body.


These tests are not routinely available at your doctor’s office because they require special equipment.

Technical - Xylene - C8H10

  • Belongs to BTEX a substance group
  • Clear, colourless flammable liquid
  • Sweet smelling
  • Detectable in the air 20ppm
  • CAS Number: 108-33-3
  • LTEL - 50ppm (220 mg/m³)
  • STEL - 130ppm (441mg/m³)
  • Risk Phrases: R10, 20, 21, 22, 36, 37, 38
  • Safety Phrases: S25

The term Xylene refers to a mixture of three aromatic hydrocarbon isomers (substances that are composed of the same elements in the same proportions but differ in properties because of differences in the arrangement of atoms).  Xylene is a clear, colorless, sweet-smelling liquid that is very flammable.  Xylene is an association of the substance group of  Benzene, Toluene, Ethyl Benzene and (Xylene) (BTEX).


Xylene  is also known as Dimethylbenzene, Methyltoluene, Xylol.   It is a mixture of the three Xylene isomers -ortho (o-xylene), meta (m-xylene) and para (p-xylene), with possible trace amounts of Ethyl Benzene. It is also referred to as xylenes (mixed).

Xylene is used as a solvent to manufacture gasoline, as a raw material for the production of organic chemicals used to make polyester fibres and to make dyes and insecticides. Other uses are in sterilizing catgut and in microscopy. The main source of Xylenes has been from reforming petroleum fractions.


o-Xylene is used almost entirely as the feedstock forphthalic anhydride manufacture, and for the preparation of phthalonitrile which is converted to the copper phthalocyanine (a colour pigment). m-Xylene is used for the manufacture of isophthalic acid and to a lesser extent, isophthalonitrile, which is the starting material of the fungicide tetrachloroisophthalonitrile.  p-Xylene, the most important commercial isomer, is primarily converted for use in fibres, films, or resins, including polyester fibres which are used for household fabrics, carpets and clothing.  Synonyms for Xylene are Dimethylbenzene and Xylol. Synonyms for o-xylene are 1,2-dimethylbenzene and o-xylol. Synonyms for m-xylene are 1,3-dimethylbenzene and m-xylol. Synonyms for p-xylene are 1,4-dimethylbenzene and p-xylo.