Fracking's air pollution threat

North Carolina regulators will hold the second of two planned public hearings in Chapel Hill today to gather comments on a recently released draft report that calls for lifting the state's ban on the controversial gas drilling technique known as hydraulic fracturing or "fracking."

The first hearing, held last week in Sanford, N.C., brought out many opponents of fracking who focused on the documented threat such drilling presents to local water quality. Fracking opponents who attend tonight's hearing plan to wear blue to show support for clean water.

But a growing body of science also raises concerns about fracking's public-health impacts from air pollution.

A recent study by scientists with the Colorado School of Public Health found that air pollution from gas-drilling operations may cause acute and chronic health problems for nearby residents, with the greatest risk for people living closest to the wells. The study will be published in an upcoming edition of Science of the Total Environment.

"Our data show that it is important to include air pollution in the national dialogue on natural gas development that has focused largely on water exposures to hydraulic fracturing," says lead author Lisa McKenzie.

The study, which drew on three years of monitoring data, found toxic petroleum hydrocarbons in the air near the wells in rural Garfield County, Colo., a major gas-drilling center. The chemicals detected included benzene, which is linked to blood disorders including cancer; ethylbenzene, a possible carcinogen that causes kidney damage; toluene, a neurotoxin that's also linked to kidney damage; and xylene, another neurotoxin. As a group those chemicals are known as BTEX.

This is not the first time that researchers have raised concerns about air pollution from fracking. According to a 2011 study that also looked at the public-health impact of fracking:

In addition to the land and water contamination issues, at each stage of production and delivery tons of toxic volatile compounds (VOCs), including BETX, other hydrocarbons, and fugitive natural gas (methane), can escape and mix with nitrogen oxides (NOx) from the exhaust of diesel-fueled, mobile, and stationary equipment, to produce ground-level ozone … . One highly reactive molecule of ground level ozone can burn the deep alveolar tissue in the lungs, causing it to age prematurely. Chronic exposure can lead to asthma and chronic obstructive pulmonary diseases (COPD), and is particularly damaging to children, active young adults who spend time outdoors, and the aged … .

The heavy truck traffic typically associated with gas drilling operations also contributes to air pollution. A general environmental impact statement prepared by the state of New York estimated that fracking could increase NOx emissions by 3.7 percent statewide and by as much as 10.4 percent in the upstate area where there are large shale-gas deposits.

Last year the Environmental Protection Agency developed draft standards for air emissions from natural gas exploration and production activities. While the agency had planned to finalize the rules last month, the timeline was extended to allow for more public comment.

North Carolina's draft report on fracking acknowledges that the state would face regulatory challenges when it comes to protecting the public from fracking's air pollution hazards. As now set up, the state's Air Toxics Program requires a source of regulated air pollutants to demonstrate compliance with acceptable air-pollution levels at the property boundary, but shale gas production often occurs on leased property that may be occupied.

"An evaluation of the existing policy will be necessary to determine whether it represents adequate protection under scenarios where natural gas production is occurring on residential properties or farms," the draft report concludes. The N.C. Air Toxics Program has recently been targeted for regulatory rollbacks by the Republican-led legislature with conditional support from the Democratic administration of Gov. Beverly Perdue.

For more details about the March 27 hearing in Chapel Hill (where the town council voted this week to oppose fracking unless strong regulations are put in place), or for information on how to submit comments through the mail or electronically, click here. The state will accept comments through April 1.

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