What Does
BTEX Gases Mean?
BTEX gases are a group of common volatile organic compounds (VOCs) that naturally occur in natural gas and crude oil, and are released into the environment as a result of their refining process.
The four BTEX gases are:
- Benzene
- Toluene
- Ethylbenzene
- Xylene
In some contexts, these are more commonly referred to as BTX Gases, with ethylbenzene being implied as a subset of benzene.
Safeopedia Explains BTEX Gases
BTEX gases are harmful to human health. They have known carcinogenic and mutagenic effects and can affect the liver, heart, kidneys, and nervous system.
They are also a significant source of air pollution. These gases are often monitored in urban areas as an approximation of the overall presence of VOCs.
Prevalence of BTEX Gases
The four BTEX gases are petrol compounds. Since gasoline has a high rate of evaporation, BTEX gases are found in higher concentrations near gas stations. Natural emissions, industrial activities, and traffic are also major sources of VOCs that enter the atmosphere.
The BTEX isomers are the most common VOCs and the most abundant in the atmosphere and surface waters. Sources of BTEX pollutants include paints, resins, lubricants, detergents, rubber, and plastic.
The BTEX compounds are lipophilic in nature, which means they are easily absorbed and distributed in adipose-rich tissues such as body fat, bone marrow, and the brain. These compounds are considered potent carcinogens, especially benzene, and have adverse effects on the lungs and respiratory system. Chronic complications include blurred vision, aplastic anemia, and pancytopenia.
BTEX Gases in Brief
Benzene
Benzene (C6H6) is a colorless compound with a sweet aroma. It has a high rate of evaporation and is highly flammable. It can be found in natural gas, crude oil, wildfire smoke, and emissions from volcanoes.
Benzene is very harmful for human health. Even low levels of exposure can cause dizziness, confusion, irregular heartbeat, and tremors. Exposure to high concentrations of benzene can be fatal, while chronic exposure can lead to cancer.
The Occupational Safety and Health Administration (OSHA) sets the permissible exposure limit (PEL) for benzene at 1 ppm over an eight-our workday and its short term exposure limit (STEL) at 5 ppm over 15 minutes.
Toluene
Toluene (C7H6) is a colorless liquid with a strong solvent smell. It is in the production of resins, paint thinners, adhesives, plastic products, glues, and various other products.
Exposure to toluene has effects similar to intoxication, while chronic exposure can lead to loss of vision and hearing.
OSHA’s PEL for toluene is 220 ppm over an eight-hour day, with a ceiling limit of 300 ppm.
Ethylbenzene
Ethylbenzene (C6H5CH2CH3) is a colorless, sweet-smelling compound. It is gaseous at room temperature, highly flammable, and used in the manufacturing of styrene and as a solvent in dyes and inks.
Exposure to high concentrations of ethylbenzene can result in hearing loss, kidney damage, and formation of cancerous tumors.
OSHA’s PEL for ethylbenzene is 100 ppm over an eight-hour day.
Xylene
Xylene (C8H10) is a group of three separate compounds with very similar properties:
- Orthoxylene
- Metaxylene
- Paraxylene
Xylene compounds are colorless, greasy, flammable substances. They are used as solvents and in the manufacturing of plastics and polyester clothing.
Exposure to high levels of xylene can cause headaches, dizziness, and confusion. It is not recognized as a carcinogen, but extremely high levels of exposure can be fatal.
OSHA’s PEL for xylene is 100 ppm over an eight-hour day.
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