Is Area Source Designation for Emissions from Oil & Gas Production Activities on the Horizon?

Credit: U.S. Geological Survey Department of the Interior/USGS U.S. Geological Survey/photo by Bill Cunningham

Is Area Source Designation for Emissions from Oil & Gas Production Activities on the Horizon?

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  • 2:31PM Aug 27, 2014
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Volatile Organic Compounds (VOCs) are carbon-based, chemical compounds that evaporate easily into the air. Long-term exposure and high concentrations of some VOCs can be dangerous to human health and/or cause harm to the environment.

What’s O&G Got to Do with It?

In the United States, the Oil and Gas (O&G) industry is responsible for 12% of total VOC emissions and for 67% of the VOC emissions attributed to industrial activities. Many of these VOCs are also designated as Hazardous Air Pollutants (HAPs), pollutants that can cause cancer or have other serious health effects. HAP emissions from the O&G sector often include toluene, hexane, benzene, mixed xylenes, ethylene glycol, methanol, ethyl benzene, or 2,2,4-trimethylpentane. These HAPs “can cause damage to the immune system, as well as neurological, reproductive (e.g., reduced fertility), developmental, respiratory and other health problems.”

Uncontrolled Ozone Precursors

O&G production activities also generate 35% of the nitrogen oxides (NOx) produced by U.S. industrial sources. Both NOx and VOCs are ozone precursors. That means that they chemically react in the atmosphere to contribute to the production of ground-level ozone and fine particle pollution. When gas production activities increase, it is likely that uncontrolled NOx and VOC emissions will also increase ozone concentrations. Air quality in areas already designated as ozone nonattainment or ozone maintenance areas will be further compromised. These are areas such as much of the Ohio Valley and the east coast of the U.S., from Maine to Virginia which are defined as having air quality worse than the national Ambient Air Quality Standards outlined in the Clean Air Act Amendments of 1970.

Current Regulation

The “2012 O&G New Source Performance Standards and National Emission Standards for Hazardous Air Pollutants” is focused primarily on methane. These standards only cover VOCs if they are also designated as HAPs, and only if those HAPs originated from dehydration units or from some types of storage tanks. The standards do not cover HAPs produced by many O&G sources such as liquids unloading activities and flowback/produced water impoundments. Recently proposed updates to control methane emissions do, in fact, reduce the emissions of non-methane VOCs and HAPs. However, the updates were not proposed to control the VOCs and HAPs, but in the process of controlling methane emissions, the VOCs and HAPs are simultaneously reduced. Emission control proponents feel that these current standards do not comprehensively address either process or fugitive emissions of VOCs and HAPs, and have petitioned the EPA to institute a minimum nationwide standard for emissions from O&G activities.

Petition for Area Source Designation

In May 2014, a group of 64 environmental groups, including the Sierra Club and the National Environmental Defense Council, petitioned the EPA to evaluate air emissions from O&G activities and to designate O&G activities as an “area” source. The EPA must provide a substantive response to the petition within 180 days.

The EPA has the authority to designate O&G production activities as area sources. “Area sources” are those that do not qualify as major sources (emitting less than 10 tons annually of a single hazardous air pollutant or less than 25 tons annually of a combination of hazardous air pollutants), but which collectively present an air quality concern, particularly when located in highly populated areas. The area source designation can be used within any metropolitan statistical area (MSA) or consolidated metropolitan statistical area (CMSA) with a population in excess of one million if the Administrator determines that emissions of hazardous air pollutants from natural gas production activities present more than a negligible risk to public health.

Area Source Table
* Comments of the Independent Petroleum Association of America (IPAA) and Western Energy Alliance on White Papers on Methane and VOC Emissions in the Oil and Natural Gas Sector per the Climate Action Plan Strategy to Reduce Methane Emissions.

In section 112 of the Clean Air Act, Congress indicates that the “Federal Government health policy since the mid-1950s has been premised on the principle that there is no safe level of exposure to a carcinogen and, unless all of the sources in the category are so remote that no human exposure occurs (a circumstance unclaimed for any source category at this time), standards should be imposed and the discretion not to act would be inappropriate.”

Criteria for an Area Source

Criteria required for designation of emissions as an area source are:

  1. The sources are located in a metropolitan statistical area (MSA) or a consolidated metropolitan statistical area (CMSA).
  2. The emissions pose more than a negligible health risk.
  3. The sources meet the following criteria:
    a.  sources are located on one or more contiguous or adjacent properties,
    b.  sources are under common control of same person, and
    c.  sources belong to a single major industrial grouping (same SIC code).

Response to Criteria

  1. Many metropolitan areas throughout the U.S. where O&G activities are taking place have been designated as MSAs or CMSAs because the population exceeds one million. For example, Allegheny County (Pittsburgh area) in Pennsylvania and the surrounding counties qualify as both a metropolitan statistical (MSA) and consolidated metropolitan statistical area (CMSA).
  2. Emission control advocates feel that the toxicology and exposure studies cited in the petition demonstrate that VOC and HAP emissions from O&G activities are more than a negligible health risk.
  3. The O&G sources satisfy criteria 3b and 3c (above) and proponents of O&G emission controls argue that 3a is also fulfilled because the sources are interconnected by a network of gathering lines and pipelines.


Emission control petitioners claim that natural gas development activities emit toxic pollutants that enhance health risks such as cancer and that these health risks are increasing as O&G activities infringe on urban areas. Supporters of emissions control suggest that natural gas development emissions probably pose a much greater risk to public health than current studies indicate because O&G emission estimates and inventories are incomplete. Noted is a 2013 EPA Inspector General report on the need to improve air emissions data and strengthen the quantity and quality of data that the EPA has for the oil and natural gas production sector. In this report, the EPA Inspector General found that the, “EPA has limited directly-measured air emissions data for air toxics and criteria pollutants for several important oil and gas production processes and sources, including well completions and evaporative ponds.” He went on to say that the EPA’s emission factors are of “questionable quality.”

The EPA is tasked with evaluating the necessity of VOC and HAP emissions regulations that will be a financial burden for both the O&G industry and the government without having adequate emissions data to do so. Air sampling programs should be conducted to evaluate emissions from various activities in each of the major shale plays so that adequate data is available to determine the proper level of emission control. Newer technology that provides accurate, real-time identification of part-per-trillion concentrations of individual VOCs is available for immediate deployment in the field. This technology can supplement established VOC and HAP methods that lack the capability to provide accurate real-time identification of individual VOC and HAP compounds, are limited to ppb concentrations, or are not easily applied in the field. The technology is available to quickly provide measurements that can be used to guide good policy decisions. It is not only technically responsible but financially prudent to use it.

For more information on this technology click here.