Energy. Environment. Economy.

New study shows gas workers could be exposed to dangerous levels of benzene

Workers keep an eye on well heads during a hydraulic fracturing operation at an Encana Corp. oil well, near Mead, Colo.


Workers keep an eye on well heads during a hydraulic fracturing operation at an Encana Corp. oil well, near Mead, Colo.

A new study out this month reveals unconventional oil and natural gas workers could be exposed to dangerous levels of benzene, putting them at a higher risk for blood cancers like leukemia. Benzene is a known carcinogen that is present in fracking flowback water. It’s also found in gasoline, cigarette smoke and in chemical manufacturing. As a known carcinogen, benzene exposures in the workplace are limited by federal regulations under OSHA. But some oil and gas production activities are exempt from those standards.

The National Institute of Occupational Health and Safety (NIOSH) worked with industry to measure chemical exposures of workers who monitor flowback fluid at well sites in Colorado and Wyoming. A summary of the peer-reviewed article was published online this month on a CDC website. In several cases benzene exposures were found to be above safe levels.

The study is unusual in that it did not simply rely on air samples. The researchers also took urine samples from workers, linking the exposure to absorption of the toxin in their bodies. One of the limits of the study includes the small sample size, only six sites in two states.

Dr. Bernard Goldstein from the University of Pittsburgh School of Public Health says the study is the first of its kind. Goldstein did not contribute to the study’s research, but he has conducted his own research on benzene. And he’s treated patients exposed to the carcinogen.

“These workers are at higher risk for leukemia,” said Goldstein. “The longer, the more frequently they do this, the more likely they are to get leukemia particularly if the levels are high.”

The study looked at workers who use a gauge to measure the amount of flowback water that returns after a frack job is initiated. A spokeswoman for NIOSH says none of their studies draw any conclusions about exposures to nearby residents, but focus specifically on workers.

But Dr. Goldstein says it shows that there could be potential risks to residents as well.

“We’re not acting in a way to protect the public who are at high risk,” said Goldstein. “And we can’t even tell you who is at high risk. Yet we’re rushing ahead in a situation where all of the data are telling us that there are risks.”

He urges a similar study should take place in Pennsylvania.

“These are the kind of studies that should be done,” said Goldstein. “It should have been done a long time before this. They’re first being done now. They must be done in Pennsylvania.”

A spokeswoman for an industry group says there is always room for improvement if toxic exposures exist.

“[The study represents] a small sample size,” said Katie Brown with the group Energy In Depth. “It is limited in that respect. I think that’s the whole reason for this partnership is to study it and see how [drillers] can improve.”

Authors of the NIOSH benzene study said that more research with larger sample sizes should be done, especially since there was so much variation in the levels observed at different times and well sites. The researchers also listed a number of recommendations for industry to take to reduce benzene levels on the job site. These include changing tank gauging procedures, training workers, limiting exposure times, carrying gas monitors, using respiratory and hand protection, and monitoring exposure levels.



  • JimBarth

    The industry certainly does not care at all about the workers, and the industry certainly does not care at all about the residents in the extraction zones. The workers don’t seem to care about it. The workers choose to be employed at the rigs, and in the zones. Residents who lease, choose to be exposed to it, or, lease vacant land. I’m concerned about citizens and residents who want no part of this extraction near them. They are forced to be exposed, and no government agency, state or federal, has aided them one bit in the past 10 years of this activity. Look at the article on Louisiana in today’s ProPublica. That is a perfect example of an entire state that is controlled by the extraction, refining, and distribution companies, and the government officials, and many workers are in the pockets of the industry. Meanwhile, the Gulf of Mexico, and Louisiana, have become so polluted that it defies logic. Within 50 years, much of the southern coastal area will be under polluted water, displacing millions of people. This seems to be a given. Meanwhile, the politicians still protect the industry whose teat they suck. I have zero faith in either the industry, the politicians, or those employed by the industry, doing anything positive to correct anything. God help us, but, since we are fully responsible, God won’t lift a finger.

  • jasbunny

    Ya think? Seeing as they have to accept a non-disclosure agreement, as I understand, and use only company doctors, we’ll probably never know the gruesome health and life effects of workers just trying to do a job. Benzene is huge, and is a known carcinogen, but diesel,ground-level ozone and on and on. Plus, the fracking sand hazards, from those who mine it to those who transport it to those who work with it and the communities at every step of the way, are just coming to light. Silica dust can cause severe lung damage, even lung cancer.

  • richardguldi

    To learn more about the benefits and risks of different types of energy production, come to the Earth, Wind, and Fire Energy Summit in Dallas TX October 4-5 for updates of ground-breaking research by scientists from across the USA.

  • Kim Triolo Feil

    Comments recently closed to ask to have the New Source Performance Standards language clarified so as to make the industry acknowledge that Green Completions Equipment (ie closed, ventless, pressurized flowback tanks) to include ALL stages of flowback (the industry wants to only use separators at the end stage of flowback). Email the EPA anyway and demand it! use email address and use the attention line Docket# EPA-HQ-OAR-2010-0505, thanks.

  • clazy8

    “Dr. Goldstein says it shows that there could be potential risks to residents as well.” Could be potential? That’s a lot of hedging. I’d be interested in hearing his rationale. It’s hard to imagine residents of nearby communities being at greater risk than workers, and the study found that exposure levels for workers who didn’t gauge tanks was practically zero. “The average full-shift personal breathing zone benzene exposures (± 1 standard deviation) for workers not gauging tanks (n=18) was 0.04 ± 0.03 ppm.”

    • Industrial Hygienist

      The ACGIH TLV for Benzene is 0.5 ppm, with an action level of 0.25 ppm. Meaning, that most workers exposed to less than 0.5 ppm for 8-hours a day over the course of their lifetime, should not experience any health affects from Benzene. 0.07 ppm is not a level that has ever been shown to cause any form of cancer or adverse health effect. Even if you go ± 2 standard deviations, 0.1, (which is standard for determining confidence intervals for scientific studies) it is still below the levels which would trigger medical surveillance (1/2 of the occupational exposure limit). If this is the level for people who are on-site but not gauging, then logic would say that anyone who is much further away, say 25-100+ yards off-site would not experience much more than a minuscule fraction of that level. More data is definitely needed though, as having more data to assess an exposure is ALWAYS better than not enough, or even none at all. The UK approaches chemicals and chemical safety from the aspect of “all chemicals a hazardous until proven otherwise”. Something that I wish we would do here in the US.

  • Victoria Switzer

    so if you live a few hundred feet from their operations???? If you live in a valley surrounded by gas industry??? More research? How long do we-those of us that live in the shalefields-have to wait for the pollution reducing technology to be implemented by the “state of the art” gas industry? They need to spend some of their huge profits safeguarding the health of their own workers and the “neighbors” they share the and with.

    • Lauren Swain

      “Petron and her team also measured benzene emissions from oil and gas operations at about 380 pounds per hour — nearly eight times higher than a CDPHE estimate of 50 pounds per hour. “

  • A Mathis

    Based on comments from a family member that works in the industry, this is true! :/

  • Courtney Trombley

    Go to to see an entire county and river ruined.

    • parched

      what’s with this link?

  • Lauren Swain

    Colorado’s Front Range residents are breathing elevated benzene levels from oil and gas production every day. “Petron and her team
    also measured benzene emissions from oil and gas operations at about 380
    pounds per hour — nearly eight times higher than a CDPHE estimate of
    50 pounds per hour. ”

  • Penn

    Benzene is a by-product of oil production. However it can appear in oil wells as the oil breakdowns. The Marcellus Shale in Pennsylvania is considered a Dry Gas in the areas that most of the development is happening. Dry Gas means no oil. No oil means NO Benzene. No Benzene means no environmental issues. No issues means no psycho-enviro campaigns to beg for more money to sustain their parasitic lifestyle.

    The Reporter should have spent some time researching where Benzene comes from and why it would be present at all. Since Benzene is an aromatic hydro-carbon that is used in Gasoline created AFTER the refining is done, there could be only the naturally occurring Benzene in any well. There is no use of Benzene in a drilling procedure, so there is no reason to have any on-site or in barrels. The psychos will argue there is Benzene in the gasoline used by the vehicles, but that is regulated and gives no reason why there would be any in the wells.

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