More than Methane: Volatile Organic Compounds


Jul 06, 2023

Volatile Organic Compounds

It’s not just methane: Oil and gas wells can also release volatile organic compounds (VOCs) that are hazardous to human health. According to the EPA regulations, VOCs are defined as “any compound of carbon, excluding carbon monoxide, carbon dioxide, carbonic acid, metallic carbides or carbonates, and ammonium carbonate, which participates in atmospheric photochemical reactions.” (40 CFR 51.100(s)) As chemical substances which react with light, VOCs act as precursors for the formation of ozone, a primary component of smog.

The definition also includes a list of chemicals not defined as VOCs. Some of the industry’s commonly produced organic compounds – methane and ethane, carbon dioxide, nitrous oxide, hydrogen sulfide, and fluorinated gases – are not defined as VOCs: they are greenhouse gases.

Forgotten Wells

A Pennsylvania-focused study of abandoned wells captured and analyzed well emissions and discovered that one of the VOCs released is benzene, a potential carcinogen. Especially concerning is the fact that Pennsylvania may have 250,000 such abandoned well sites, with almost 25% of them within 300 feet of residential areas and public buildings. Many are unmarked: homeowners and visitors may not even be aware of their existence. Homes and businesses are sometimes built right on top of abandoned wells.

One of the study co-authors, Eric Lebel, said of abandoned wells, “it’s not just a climate concern but also a health concern.”

Health Risks

Abandoned wells can emit a variety of VOCs, which are linked to risks of cancer, asthma, neurological, immune system, and developmental problems as well as reproductive issues. VOCs are actually found in many common industrial and household products: building materials, petroleum products, and personal care items. Some large consumer companies are facing lawsuits for potential harm caused by personal care products.

While methane escaping from wells is the primary environmental concern due to climate warming, benzene is a known human health risk, as exposure to benzene is associated with multiple types of cancer and can aggravate asthma symptoms and complications.

VOC Measurement

Measuring the levels of VOCs and particularly benzene that are emitted from abandoned wells is difficult, and methods of determining rates of VOCs in gas streams are still being researched. As with methane, measuring VOC movement through soil in a concern that cannot be accurately assessed. This leads to concerns about soil and water contamination. Preliminary data show that Pennsylvania’s abandoned wells may be releasing benzene at lower concentrations that other US well locations.

The EPA estimates there are over 3 million abandoned wells across the United States, ranging from fully plugged and sealed to completely unmarked and/or undocumented, and potentially leaking toxic fluids, greenhouse gasses (methane), and VOCs (benzene and others).

The EPA is reevaluating pollution regulations for oil and gas, currently focusing on emissions from active production operations and equipment, rather than abandoned wells emissions.

Sealing Leaks

Locating these abandoned wells and evaluating the risks (to health and the environment) is a challenge. Once they are found and the emissions accurately measured, plugging and sealing to reduce releases of methane and potentially hazardous VOCs like benzene is the path to protecting both human health and slowing climate warming. BioSqueeze® provides the most effective solution for sealing leaks, forming limestone (a natural gas-tight caprock) in leakage pathways to permanently sequester escaping gases.