BTEX (Benzene, Toluene, Ethylbenzene and Xylene) Test

BTEX is not a single chemical, but a group of chemical compounds that primarily include: benzene, toluene, ethylbenzene and xylene. BTEX consists of naturally occurring chemicals commonly found in petroleum products such as gasoline. In other words, BTEX is an acronym for the four common volatile organic compounds (VOCs) found in industrial environments. These are well-known hazardous compounds found in a wide variety of facilities and products, but all occur naturally in crude oil and natural gas. Their escape into the environment is largely a result of the refining processes of each, and they are also used in a variety of industrial and pharmaceutical processes.

A closer look at these volatile organic compounds (VOCs):

• Benzene: This colorless, sweet-smelling compound evaporates quickly and is highly flammable. It occurs naturally as a component of crude oil and natural gas, and can also be found in smoke from volcanoes, forest fires, and cigarettes. The compound can be captured during the crude oil refining process. It was once an important gasoline additive used as a substitute for lead.

Benzene is extremely harmful to humans. Low levels of exposure can cause drowsiness, dizziness, confusion, rapid or irregular heartbeat, and tremors. Long-term exposure to benzene is known to cause cancer. Extremely high benzene concentrations are fatal. According to the U.S. Environmental Protection Agency (EPA), gasoline should not contain more than 0,62 percent benzene by volume. The U.S. Occupational Safety and Health Administration (OSHA) has set the permissible exposure limit for benzene at 1 ppmv for an eight-hour workday. It has also set a peak limit of 15 ppmv for 5 minutes.

• Toluene: A colorless liquid with a strong solvent odor. It is a minor component of crude oil captured during the refining process and used in the production of glues, resins, solvents, thinners, polishes, nail polishes, adhesives, and plastic products. People exposed to toluene experience effects similar to drunkenness. Long-term exposure can cause vision and hearing loss. It is not a recognized carcinogen. OSHA has set the permissible exposure limit for toluene at 200 ppmv for an eight-hour day.
• Ethylbenzene: This colorless, pleasant-smelling compound is gaseous at room temperature and is highly flammable. Ethylbenzene, obtained from crude oil during refining, is commonly used in the production of styrene. It is also widely used as a solvent in inks and paints and is a byproduct of the combustion of motor fuel. Exposure to high levels of ethylbenzene can cause hearing loss and kidney damage. It can also lead to the formation of cancerous tumors. The EPA requires that drinking water contain no more than 700 ppbv of ethylbenzene. OSHA has set the permissible exposure limit for ethylbenzene at 100 ppmv for an eight-hour day.
• Xylene: The compound comes in three isomers (same chemical formulas with different structures). It is a colorless, oily, flammable substance used in the manufacture of plastics and polyester clothing. It is also widely used as a solvent. Exposure to high levels of xylene can cause headaches, incoordination, dizziness, and confusion. Exposure to high levels for short periods of time can cause skin irritation. It is fatal at extremely high levels, but is not considered a carcinogen. The EPA requires drinking water to contain no more than 10 ppmv of xylene. OSHA has set the permissible exposure limit for xylene at 100 ppmv for an eight-hour day.

Emissions of BTEX compounds can be measured actively or passively:

• Active measurement: Gas chromatography mass spectrometers are installed in facilities to collect air samples. These systems can determine total volatile organic compound (VOC) emission concentrations as well as concentrations of individual compounds in minutes. However, these systems are much more complex and therefore much more costly.
• Passive measurement: Rosettes or tubes that adsorb or collect BTEX compounds in known proportions are placed at monitoring points and then collected. Samples are then sent to laboratories where BTEX concentrations are identified using ion chromatography or plasma mass spectrometry.

Locating measurement equipment outside a facility is critical. Unpredictable environmental conditions mean that readings will become less accurate the further equipment is located from an emission point.

Because BTEX is so heavily regulated around the world, there are many ways to eliminate it, these include:

• To isolate compounds during refining or manufacturing processes and prepare them for reuse or sale elsewhere.
• Using existing treatment technology, including biodegradation or adsorptive filtration.
• Removing and burning compounds from processing or production.

Some removal methods solve the problem more completely than others. For example, reusing or selling BTEX compounds only delays their eventual emissions. Activated carbon filters are expensive and must be replaced frequently as their performance deteriorates over time. Burning BTEX compounds is as bad as allowing them to escape untouched, as one of the byproducts of their combustion is carbon dioxide.

There are other natural ways to eliminate BTEX compounds. For example, some of the compounds are degraded in natural sunlight. The compounds can also be metabolized by microorganisms under both aerobic and anaerobic conditions.

Our organization has a strong staff that closely follows the developments in the world in the field of science and technology and constantly improves itself. Among the numerous test, measurement, analysis and evaluation studies provided for businesses in various sectors, there are also BTEX (benzene, toluene, ethylbenzene and xylene) testing services.