BTEX exposure is an increasing public health concern

Unconventional oil & gas facilities (UOG) such as this compressor station along Hwy 6 near Rulison are common sources of ambient BTEX pollution in western Garfield County. For more videos take the Garfield County FLIR Tour.


This just in from The Endocrine Disruption Exchange (TEDX) —

tedx thumbNew Look at BTEX: Are Ambient Levels a Problem?

In a review published today in the peer-reviewed journal Environmental Science and Technology, TEDX researchers Ashley Bolden, Carol Kwiatkowski, and the late Theo Colborn found that exposure to ambient levels of benzene, toluene, ethylbenzene, and xylene (known together as BTEX) are linked to hormone-related health conditions in humans. Health effects from each chemical individually or in combination include sperm abnormalities, reduced fetal growth, low birth weight, cardiovascular disease, respiratory dysfunction, asthma, sensitization to common antigens, and more. Two-thirds of the 42 studies found effects in children, some of whom were exposed prenatally, when effects can be permanent.

BTEX are most well known as products of combustion exhaust, and more recently as pollutants from unconventional oil and gas operations (drilling and hydraulic fracturing). Much higher levels can be found indoors due to off-gassing from products like household cleaners, fabric treatments, building materials, furniture and automotive products. Health effects summarized in this review were found at exposure levels commonly found indoors and outdoors in the U.S., and at levels deemed ‘safe’ by the U.S. Environmental Protection Agency.

Exposure to BTEX is a growing concern for public health. At a minimum, greater attention should be paid to improving indoor air quality by removing harmful chemicals from consumer products. Development of chemicals that are not hormonally active is urgently needed. Government agencies should also require monitoring of air and water near oil and gas wells and facilities to determine how humans are exposed. Most importantly, the federal government should establish and enforce more protective air standards so that citizens can live, work, learn, and play in a healthy environment.

Study findings and implications

Benzene, toluene, ethylbenzene, and xylenes are four chemicals frequently found together and referred to as BTEX. In our review we collected studies assessing the health effects of BTEX exposure at low (everyday) levels considered safe by the US EPA.

Evidence from studies in humans suggests that we should be concerned about the connections between BTEX exposure and reproductive, developmental, respiratory, and immune effects. Specific effects include sperm abnormalities, reduced fetal growth, low birth weight, cardiovascular disease, respiratory dysfunction, asthma, sensitization to common antigens, and more. Some effects were seen from exposure to the BTEX chemicals individually, and others were from exposure to the combination.

Below are specific findings from the review and our assessment of the implications of those findings.

FINDING: BTEX exposure occurs from indoor off-gassing from household products, and exposure levels can be much higher indoors than outdoors.

  • IMPLICATION: Research is needed to determine the greatest sources of indoor exposure so that they can be reduced or eliminated.
  • IMPLICATION: Household products should not contain chemicals that have biological activity at low concentrations. For example, safe replacements are needed for chemicals in building materials (paints, wallpaper etc.), furniture, and household cleaners. Government support is needed for the development of safer alternatives to such chemicals.

FINDING: People are exposed to BTEX through vehicle exhaust, and BTEX exposure also occurs from unconventional oil and gas development (e.g. hydraulic fracturing).

  • IMPLICATION: As oil and gas development (UOG) advances rapidly into neighborhoods around the world, the number of people living near UOG is increasing dramatically. The government should require industry to monitor the air from UOG and enforce pollution limits that protect the health of people, wildlife and the environment.
  • IMPLICATION: Exposure and symptoms of citizens living in close proximity to UOG should be studied, in order to identify ways to prevent harmful exposures.
  • IMPLICATION: BTEX are added to gasoline to prevent the fuels from spontaneously igniting. Thus one of the highest sources of BTEX emissions is from vehicle exhaust. The continued use of BTEX in fuel formulations should be reevaluated and safer alternatives should be developed.

FINDING: Health effects were observed at exposure concentrations considered safe by the U.S. EPA.

  • IMPLICATION: The current methods by which government research sets ‘safe’ levels of chemical exposure are flawed. Relatively high exposure levels are tested for health effects such as death or changes in organ weight. These endpoints are not sensitive enough to detect critical changes in endocrine function. By assuming that lower doses are always safer, the government has set exposure levels they hope will be safe, however these levels have not been tested for health effects that can occur from exposure to low concentrations. There is an urgent need to change the system so that chronic long-term health effects are assessed at exposure levels currently experienced by the general population.

FINDING: Many different hormones can be involved in the health effects associated with exposure to BTEX.

  • IMPLICATION: The endocrine (hormone) system responds to very low concentrations of chemicals. Research is needed on the hormonal mechanisms that may be responsible for the health effects associated with BTEX exposure. Such research should focus on exposure concentrations currently experienced by humans. Government funding for endocrine research is urgently needed.

FINDING: Sixty four percent of the studies reviewed found effects in children, some of whom were exposed to BTEX prenatally.

  • IMPLICATION: Prenatal and early childhood exposure to BTEX can lead to permanent effects. Medical and clinical professionals need to be aware of the importance of the role of exposure to endocrine disruptors during prenatal development. Recommendations for how to avoid exposures to BTEX should be developed and shared widely.

Download the 16-page review: New Look at BTEX: Are Ambient Levels a Problem?

Lead author Ashley Bolden will discuss the results during a teleconference call on Wednesday, May 20, 2015, at 1:00 p.m. EST.

Study points to chemicals’ health threats

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