Q&A: Colorado’s Chief Medical Officer on the health impacts of fracking

Last month, The Greeley Tribune published a story with the headline “Weld County health incidents level with rest of state, despite more oil and gas development.” In it, Dr. Larry Wolk, the executive director and chief medical officer of the Colorado Department of Public Health and Environment, discusses CDPHE data that shows no greater levels of health problems in gas-heavy Weld County than in other counties across the state. Wolk was appointed to his current role in 2013 after several years as the chief executive officer of  CORHIO, Colorado’s nonprofit health information exchange. In the story, he spoke out against the characterization of oil and gas development as harmful to human health, stressing the difference between direct and indirect exposure when it comes to oil and gas pollution.

“I’m not going to tell anybody to go drink a pint of liquid petroleum or stand over an active well site and wave the fumes in to breath them in,” Wolk said. “Nobody would argue that this stuff isn’t toxic, but it’s all about exposure to toxins, and we don’t see anything to be concerned with at this point in time.”

The Colorado Independent called Wolk to hear more about that story, the data he discussed, and what kind of protection Coloradans can expect — or not expect — from oil and gas development in their communities in the near future.

Note: This interview has been slightly edited for length and clarity.

The Colorado Independent: To start, could you briefly summarize for our readers what your role is as Chief Medical Officer? What is your main objective, and what kind of role do you play in protecting the interests of Colorado and Coloradans?

Dr. Larry Wolk: Well, there are a couple of things, but serving as the executive leader for the Colorado Department of Public Health and Environment means that I aim to ensure the public’s access to the best possible health and the best possible environment. I act as an advocate for that, both with the governor and for the governor, as well as for the department when it comes to making sure that we have a lens on health equity and environmental justice and making sure that everyone has access to the best health and environment as possible.

CI: I’d like to start by talking about a story that came out in The Greeley Tribune earlier this month that referenced a study showing Weld County doesn’t see a higher incidence of fracking-related health impacts despite having significantly more wells. Can you talk about the design and results of that study?

LW: Well, first of all, there was no ‘study.’ [The CDPHE was] asked to look at a table of data that was put together by one of the oil and gas companies — I can’t remember which one — to see if we stood by the numbers that it had pulled from one of the databases that we had made publicly available. The first thing we do is make sure that it is our data and make sure that it is credible, and we said yes, that’s our data, and yes, it’s credible. What the data shows is that from a registry standpoint — we maintain registries based on a number of health conditions, whether it’s cancer, birth defects, etc.— that the rates of these different health concerns or issues in some of these oil and gas-rich communities were no different from those that were not in oil and gas-rich communities. It was maybe misrepresented as a “study” by [The Greeley Tribune], but it was not a study.

CI: So, it was actually an analysis — can we call it an analysis — ?

LW: Yeah, based on a publicly available database.

CI:  So, the analysis shows that Weld County does not have significantly more instances of asthma, birth defects, infant mortality or low birth rates than other Front Range counties. But a recent report released by the Clean Air Task Force shows that Colorado has the third-highest number of oil and gas-related health incidents out of any state in the U.S., despite having what the state calls the toughest regulations in the country. The lead author of the study attributed the persistent health problems partly to the fact that air pollution doesn’t stay within state borders. Does it make sense, then, that the effects of oil and gas development would obey borders enough to isolate effects to the county level?

LW: Not necessarily. And I think somebody raised the point, too, that the effects would be diluted — that a county can really be pretty expansive, so you could have a lot of development in one little corner of the county and not much in the rest of the county, and see a cancer rate that’s no higher than in a neighboring county. So there is definitely room for caveats, if you will. I don’t rule out caveats — I like to make sure people understand all the caveats. The point of The Greeley Tribune story, and the statements that I made in it, is that this question of exposure is much more relevant than the actual fracking process itself or the oil and gas processes themselves. It’s just like if you were talking about cigarette smoke, paint thinner, dry-cleaning, what have you. Nobody would argue that these substances aren’t toxic, nobody would argue that they aren’t bad; they are toxic, and there’s all kinds of work in science that says concentrated benzene exposure can lead to all kinds of health effects, cancer effects. But what levels of exposure are you talking about at certain safe distances, protective distances, if you will?

CI: Does the health department have data about instances of health problems over time, before the increase in oil and gas development in Colorado? What does that data say?

LW: I don’t have right off the top of my head what we see an increase of versus or what we see a decrease of. I will say that we see the kind of continued, expected increases based more on age and genetic profile than anything that’s being done here in the state. You know, prostate and breast cancer continue to be the dominant forms of cancer, but those both have more to do with the ages of people who live here and their genetic backgrounds than anything that the state is doing.

Asthma has been flat and high for quite a while, although, because we have a state where people are coming and going a lot, it’s hard to look statewide. You can look at our website and see what that sort of prevalence has done in terms of trends. From a pollution standpoint, we have been relatively stable, and have actually seen some improvements in some types of pollution. Particulate matter is way down — we don’t have the brown cloud like we used to — and ozone we’ve been able to regulate to a level that certainly isn’t getting any worse, and, in some respects, is actually getting a little better. Based on the data on our website, you can’t tie the emissions to the diseases, but you can certainly look at the disease incidents themselves.

Lung cancer, for example, statewide was 55 incidents per 100,000 people in 2004, and now it’s hovering somewhere around 40 per 100,000. So we’ve seen at least a decrease in age-adjusted incidences of lung cancer in the last 10 years.

CI: University of Colorado researcher Lisa McKenzie worked on a study published in 2014 that shows that certain birth defects are as much as 30 percent more common among mothers living near natural gas wells. You pointed out — and she agreed — that correlation does not prove a causal relationship. But would it not make sense to apply the “prevention principle” here? If there’s even a small indication that something is harmful to public health, why not take action as soon as possible? Why not make public health the top priority?

LW: Oh, it is, it definitely is. But I think the limitations to that study, which Dr. McKenzie would agree to, make it really difficult to apply. First of all, the [oil and gas] well data that was used in that study used a combination of open, shut-in and inactive wells, not just active wells. Second, the data was based not on residence, but on where the mothers delivered their babies, and we know that a lot of people, especially rural people, can travel quite a distance to deliver their babies. The correlation [between birth defects] and where you deliver your baby doesn’t hold up quite as well as the correlation to where you live. [NOTE: The study assumed that a mother’s address at time of delivery was the same as her address during the first trimester of pregnancy — the critical time period for formation of birth defects. Some studies have shown that up to 30 percent of mothers move during their pregnancy, “potentially introducing some exposure misclassification for the early pregnancy period of interest.]

There was also, if you were making the inference that living near oil and gas wells leads to an increase in certain kinds of birth defects, there were also some birth conditions that actually seemed to decrease in incidence, like cleft palates. We think that this is the kind of research that needs to be done, but certainly there were enough limitations that kept us from saying that we need to increase setbacks or reduce oil and gas activity or whatever.

CI: Health concerns were a major motivator for Colorado’s two anti-fracking ballot initiatives, which ultimately failed to make the ballot. What are your thoughts on these initiatives, considering both that 100,000-plus community members called for the protection of their health and that you yourself are an expert in public health?

LW: So, it’s really on your second point that my role fits in. I try to provide some technical assistance to these kinds of things, because I don’t have an official opinion that should matter. I’m a regulator. It’s the will of the people as to what they vote for, and it’s my job to take into account public health and environmental health and work with it. The second part of the statement is where I sometimes take issue.

I think people often invoke public health or health concerns when we don’t necessarily have evidence that there is a valid health issue. There are certainly other issues that are valid as to why people don’t want these things near them: They don’t like the noise, they don’t like the smell, they don’t like the traffic, they don’t like the appearance. I’m not invalidating those, at all — I certainly wouldn’t like to live in a neighborhood near those, either — but I can’t, in my role, allow that to be a substitute for saying that this is bad for public health. We don’t have any demonstrative evidence that increasing the setbacks from oil and gas development would be any more protective of the public’s health than where the current setbacks are, because we don’t have any evidence that there is a public health impact as a result of the current setbacks.

We don’t have any evidence that 500 feet is the wrong number. It might be the wrong number as it relates to noise, or to ‘I don’t like seeing it,’ or as it relates to truck traffic, but those aren’t really health issues. We have evidence that being five feet from an active well 24/7 is not good. With that kind of exposure, we see irritation and the potential to inhale directly benzenes and things that cause chronic diseases and cancer. So trying to find that right number [for a setback distance] is I think the right thing to do, but we just don’t have any credible evidence that 500 feet or 1,000 feet is not enough, that increased setbacks would be any more protective of public health than the current setbacks.

There are always ongoing efforts by researchers to try to measure the effects of oil and gas development, to see if there are any spikes in health problems as it relates to that, but it’s an ongoing effort.

CI: So what kind of threshold, in terms of evidence that oil and gas development has an impact on public health, would be required for the state to take action?

LW: One is studying air emissions. We just received the most comprehensive inventory of air emissions from Colorado State University to date, and so what we can do now is we can model that. Based on what the air monitors have detected as far as pollution levels in the air, we can now model that to say, ‘what’s the risk of cancer, what’s the risk of asthma’’ just by knowing what a good, solid air inventory shows us. We should have that modeled by next summer, so we’re hoping within the next year that that might give us some information that might cause us to act. And from the research community, we need well-designed studies that can overcome some of those limitations that we just talked about. We aren’t an academic institution, so we rely on academic institutions to conduct the kind of studies that Lisa McKenzie is working on. We want to see a body of research developed that can overcome some of those limitations.

CI: What would you say to people who feel, particularly given that the oil and gas industry is so powerful in this state, that data and information surrounding the environmental impacts of oil and gas development is biased?

LW: I think it’s fair. I think we live in a state where we have bias on both sides. We have a very strong advocacy community for oil and gas development, and we have a strong advocacy community for environmental protections. I would like to think that the CDPHE is one organization that can really try to stay unbiased and evidence-based and objective when it comes to putting forth truthful information. It’s not that either of those two sides would put forth untruthful information, but you can use data sometimes to make your point on one side or the other. So you have to be able to rely on somebody to be objective when it comes to balancing the playing field there.

I would like to think that is our department, but as you said, I think you have a governor — and I think our governor does a good job of balancing between environmental health and oil and gas development — but if somebody is suspicious of the governor, that would lead them to be suspicious of the health department, too. My goal is to be objective, but people will think what they want to think sometimes.

Official photo via Colorado.gov


  1. Well, you might want to talk to my brother who lived in Weld county about that. The effects of fracking nearly killed him. If you think this ISN’T having effects on people, then you are IGNORING the people. Because there ARE effects and they can be devastating. Anyone who says that this is a fine, clean way of getting energy from the ground is being PAID to tell you that or is a complete fool.

    As if the petro issues weren’t bad enough, what IDIOT thinks that you can go around destroying your bedrock and NOT have issues from it? Ask Oklahoma about that, they seem to be having just a LITTLE bit of an issue with earthquakes shaking their state rather seriously to the tune of about 3 a day. They used to have about 6 a YEAR.

    Anyone who lived in the Denver-Boulder area back in the 60’s remembers the earthquakes we had here then. Those happened thanks to the high pressure injection waste disposal down at Lowry Air Force base. As soon as they stopped doing that, the quakes stopped. SURPRISE! Good God, people, it’s time to be SMARTER rather than to just sit here destroying the very ground we walk and build on so that a very few people can get stinking rich. The rest of us just end up with a stinking state we can’t live in any longer. Is that REALLY what we want for Colorado?

    Not me.

  2. Yes, I agree that disturbing “bedrock” over a long period of time is going to have consequences. We cannot continue to treat the earth as though we are not connected to it. Our “public health” is dependent on the health of our planet, and recognizing that connection needs much more attention. My 2 cents.

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