Study points to higher emissions near Northern Colorado oil, gas sites

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By Jeremy Johnson

NORTHERN FRONT RANGE — Residents of Northern Colorado living near wells or in areas with increased oil and gas extraction may be subjected to ambient atmospheric hydrocarbon levels at or higher than levels found within major urban areas, according to a recent article published by a nonprofit academic group.

The study, published Nov. 14 by Elementa: Science of the Anthropocene, and penned by three atmospheric scientists with ties to the University of Colorado in Boulder, claims emissions from oil and gas development in northeastern Colorado are compromising air quality, despite a 2008 tightening of emissions standards for oil and gas industries known as the Fugitive Emissions rule. 

In the recent academic study, “Influence of oil and gas emissions on ambient atmospheric non-methane hydrocarbons in residential areas of Northeastern Colorado,” authors Chelsea R. Thompson, Jacques Hueber and Detlev Helmig found that concentrations of non-methane hydrocarbons (NMHC) present in residential areas located near wells in Erie were “significantly higher than expected.”

The trio found NMCH concentrations were 18 to 77 times greater than regional background and, in some instances, those concentrations — which are also attributed to vehicle pollution in addition to O&G industry emissions — were higher than what is typically found in “large urban centers.

“When combined with NMHC observations from downtown Denver and Platteville, it is apparent that these compounds are elevated across the (northern Front Range), with highest levels within the Greater Wattenberg Gas Field,” authors wrote in their introduction. “This represents a large area source for ozone precursors in the (northern Front Range).

In Erie, those “precursors” — which the scientists say can cause “respiratory distress” — include “comparable” levels of the elementary petrochemical and carcinogen, benzene, whereas other hydrocarbons such as toluene, ethylbenzene and xylene are higher than normal but lower than levels in large urban areas. However, in nearby Platteville, authors said benzene levels were “significantly higher,” and pose a threat to public health.

“Benzene levels in both Platteville and Erie/Longmont could be detrimental to human health if chronic lifetime exposure should occur,” authors wrote.

“An initial look at comparisons with data sets from previous years reveal that ambient levels for oil and gas-related NMHC in Erie, as well as further downwind in Boulder, have not decreased,” authors added, “but appear to have been increasing, despite tightening of emissions standards … in 2008.”

As ozone precursors, NMHCs could also present a larger problem down the road, authors said. 

“Apart from concerns related to primary NMCH emissions, ozone is also a health concern, as elevated levels of ground-level ozone can lead to respiratory distress,” authors added. “Unlike the NMHC emissions, ozone is a secondary pollutant that can often be formed far from the source of the precursor compounds, and thus becomes a regional problem.”

Fracking is the backbone of expansion

The study’s authors said the increase in oil and gas development in northeastern Colorado and throughout the state is the direct result of advanced techniques in hydraulic fracturing, or fracking, coupled with abundant natural gas and oil supplies found within the Denver-Julesburg Basin (DJB). As a result, authors said the DJB is home to more than 25,000 active wells, 24,000 of which are located within Weld County.

Authors also attribute the natural gas boom to the Greater Wattenberg Field, located within the basin. Vast available resources and advancements in technology have led to Colorado’s ranking as the sixth-highest state in terms of active natural gas wells, at about 32,000 statewide in 2012, authors wrote.

“The rapidly expanding use of fracking in Colorado … has led to growing environmental and public health concerns, primarily relating to air and water quality,” authors wrote. “A growing body of scientific research is finding that emissions of (NMHC) from oil and gas drilling and related activities are leading to poorer air quality, contributing to high ozone episodes and causing health concerns.”

However, the article goes on to suggest that it is not necessarily just the number of active wells in northeastern Colorado contributing to an increase of emissions, but the location of many of those wells, too. While 2012 regulations established lengthier “setbacks” of 350 to 500 feet, those regulations did not apply to already existing wells.

“While oil and gas development has traditionally been conducted in rural areas, this dynamic has been changing in recent years, with an increasing number of wells being drilled in residential and municipal locations, posing new questions related to health impacts of oil and gas emissions,” authors said, noting that some community groups along the Front Range have successfully lobbied for moratoriums against fracking. 

Such postponements were passed in 2013 in Boulder, Fort Collins and Lafayette, and Boulder County commissioners agreed — just one day before the Elementa article was published — to extend their moratorium through 2018.

Authors of the study said those who have lobbied for fracking freezes want more comprehensive scientific research, but said oil and gas reports relating to health impacts are hard to come by.

“Health impact studies … are sparse, and challenging due to the chronic nature of such exposures,” authors said. “However, a recent study … conducted in Garfield County found that residents living within a half-mile of wells were at greater risk of health impacts relating to NMHC exposure, such as to benzene, a known carcinogen.”

Emissions restrictions not the only answer

To determine the source of NMHC along the Front Range, scientists, working out of the University of Colorado’s Institute of Arctic and Alpine Research, said they studied the makeup of dozens of hours-long samples collected between March and June of 2013 in Denver, Erie, Boulder, Longmont and Platteville. What they found is, though there are similar levels of NMHC in urban Denver and rural Platteville, the makeup of compounds reveals a different source for those hydrocarbons.

“The comparison of the aromatic species between Denver and Platteville is of interest given that these two locations are quite different,” the study reads, “with Denver being a highly populated urban center (of about 2.2 million) and Platteville (2,600 residents) being a rural town located within the Wattenberg Field. Benzene, in particular, is significantly higher in Platteville than in Denver.” 

According to authors, the higher correlation of propane found in NMHC near Platteville compared to Denver’s acetylene correlation means all fingers point to oil and gas drilling as the root of the rural hydrocarbon levels, unlike in Denver where vehicle emissions “and other urban, combustion sources” contribute to the majority of pollutants. However, scientists ultimately conclude that Platteville’s NMHC levels are likely multi-faceted.

“The proximity of Platteville to (Route 85), a well-traveled, north-south corridor between Denver and Greeley, may explain some of the enhancement in (exhaust and/or urban tracer compounds) at the Platteville site,” the report reads. “Additionally, industrial activities in support of the oil and gas industry may also contribute, including emissions from generators, compressors or diesel engines used during the drilling phase, and high volumes of heavy truck traffic, especially during the hydraulic fracturing phase.”

A number of emissions regulations have been passed in the past half-decade or so, and authors of the study said 2014’s Air Quality Control Commission tightened the oil and gas industry’s volatile organic compound (VOC) emissions standards — along with vehicle tailpipe emissions standards — even more. Authors said the latest regulations push aims to capture 95 percent of NMCH emissions.

Health concerns aside, the state has little choice in implementing stricter standards, as all the Front Range communities included in the Elementa study have been, since 2007, federally designated as non-attainment areas. Such areas are defined by air quality that falls below national ambient air quality standards, and the federal designation requires implementation of plans designed to meet federal standards — failure to do so can result in loss of regular federal funding. 

But authors suggest emissions regulations are not the only answer.

“Even though the volume of emissions per well may be decreasing, the rapid and continuing increase in the number of wells may potentially negate any real improvements,” authors concluded. “These findings, and the continuing development of this region, provide a strong argument for the continued atmospheric monitoring of this region in the coming years.”

For more information or to read the whole study, go online to www.elementascience.org.