Tuesday, June 26, 2012

Can Gas Drilling Emissions Cause Heart Attacks?

That's the question I raised a month ago when writing about the need for health impact studies. Anecdotal evidence in one Barnett Shale community found an increase in the rate of heart attacks and exposure to drilling emissions.

People living near wells are exposed to a whole host of potential pollutants, many airborne.  For example, they breathe in volatile organic chemicals much higher than what's considered "potentially harmful" to public health. And drilling sites aren't the only problem: airborne toxins from compressor stations are finding their way into people's lungs and bloodstream. They also breathe in more particulates.

But one of the real killers hiding in the emissions may be ozone - not an emission itself, but something created when nitrogen oxides combine with volatile organic compounds in the sunlight. It's such a concern that NY's Department of Environmental Conservation (and PA's Department of Environmental Protection)  issues "ozone alerts" on very hot days, warning people to stay inside.

Now new research shows that high levels of ozone can increase the risk for heart attacks and stroke. EPA toxicologist Robert Devlin exposed healthy young volunteers to high levels of ozone - levels that reflect the same cumulative dose they would receive had they been working outside for eight hours in a place like Los Angeles. Or the Upper Green River Basin of Wyoming, where ozone levels can get as high as 124 parts per billion (ppb)  - that's way over the US federal limit of 75 ppm and higher than Los Angeles on its smoggiest day.

The problem boils down to inflammation. Ozone exposure triggers high blood levels of inflammatory agents that stick around in the blood for a long time. In turn, the body could perceive the inflammation as a wound and turn on a clotting response, potentially blocking blood flow. Ozone also changed the levels of some proteins involved in blood clotting and affected the heart rate.


  1. Dear Sue--You are right on the money as far as ozone is concerned. Ozone is one of the very worst pollutants. Not only does it increase the risk for heart attacks and strokes, but it causes many cases of asthma, especially child hood asthma at rates as high as 25 percent in areas that are heavily drilled in the west. (Per TEDX.) Ozone will have a deleterious effect on any living organism at vanishingly low concentrations. Just another reason to band not only hydrofracking, but any industry dependent upon diesel engines and fossil fuels in general. Take care. Tom

  2. I do wish you had gone on to say what the researchers found to have happened to those young healthy volunteers.

    1. Carrie, if you click on the link at the beginning of the next to last paragraph, you can read an article about the report. An excerpt follows:

      In the new study, blood levels of several inflammatory agents increased after ozone exposure — sometimes more than doubling —throughout a period that lasted more than a day. This “caught us by surprise,” Devlin says, and “we think it’s one of the more important and significant findings.”

      The high ozone exposure also triggered subtle changes in heart rate variability. Although small, this points to an increased risk of arrhythmias, notes EPA cardiologist Wayne E. Cascio. Ozone also altered levels of several proteins involved in blood clotting.

  3. nice posting.. thanks for sharing.