What is a natural gas compressor station?

A compressor station is a facility that pressurizes gas to push it through the pipeline.  It usually also includes technology to remove moisture and contaminants from the gas.  Its engines can run on diesel, gas from the pipeline, or electric motors.  Compressor stations are built every 50 to 100 miles along the length of a transmission pipeline to boost the system pressure to keep the gas flowing. The pressures in transmission pipelines typically range from 500 to 1000 pounds of pressure per square inch, or psi. As a reference, automobile tires are inflated with compressed air and operate at around 30 to 50 pounds of pressure per square inch.

Who regulates pipelines and compressor stations?

The energy transportation network of the US consists of over 2.5 million miles of pipelines which are operated by approximately 3,000 companies, and overseen by the US Department of Transportation’s Pipeline and Hazardous Materials Safety Administration (PHMSA), which gathers data, sets up rules and issues reports, many of which are publicly available. PHMSA addresses minimum station safety regulations. It does not address community issues such as siting and appearance, or environmental issues such as emissions, noise, or light pollution.

How many compressor stations are there in the US?

The Pipeline and Hazardous Materials Safety Administration (PHMSA) does not maintain an inventory of compressor stations. Their task is just the pipelines. When asked, they said that there is no inventory anywhere.

What kinds of emissions are produced by pipeline compressor stations?

From permit applications we know that compressor stations emit:

·      Nitrogen oxides (NOx) which are associated with respiratory disease. Ozone is formed when NOx and volatile organic compounds (VOCs) react in the presence of heat and sunlight.

·      Volatile organic compounds (VOCs) are neurotoxins and have significant cognitive and behavioral effects. They are known hepatotoxins, reproductive toxins and fetotoxins, and have been associated with teratogenesis and fetal wastage. All are dermatotoxins.

·      Formaldehyde which is a carcinogen.

·      Sulfur dioxide (SO2 ) is associated with respiratory and neurological illness, and death.

·      Particulate matter is of small size and large surface area, and carries toxic pollutants deep into the lungs, and is a carcinogen.

The sources include the compressor engines, compressor blowdowns (accidental or scheduled), condensate tanks, storage tanks, truck loading racks, glycol dehydration units, amine units, separators, and fugitive emissions sources. In addition, accidents can occur at any point of gas production, from transport of materials to the site, to construction and operation of the facility, to the processing of the gas and the delivery of it via pipelines, and at any of those points, explosions are possible, as well as accidental releases of air toxins. 

The components of natural gas transported in pipelines include:

Methane (CH4 )

Light and heavy alkanes

BTEX - Benzene, toluene, ethylbenzene, and xylene

Hydrogen and carbonyl sulfides

Sulfur Dioxide (SO2)

Formaldehyde and other aldehydes

Particulate matter (tiny soot-like particles)

Carbon monoxide (CO)


Radon, polonium and lead

Polychlorinated Biphenyls (PCBs)

Several studies have looked at emissions from compressor stations and concluded that they are significant. A 2013 RAND study of air-quality damages in Pennsylvania determined that 60–75% of the estimated damages result from compressor station activities.

Dr. Allan Robinson of Carnegie Mellon University estimates that the greatest nitrogen oxide and VOC emissions associated with natural gas production are from compressor stations. He presented at an Institute of Medicine conference on shale gas development in Washington DC.

What level of emissions should we anticipate from the Highland compressor?

Extrapolating from known emissions from existing compressors, the 22,400 HP compressor station proposed for Highland can be expected to release about 125,000 tons of pollutants into the air each year, including known carcinogens and neurotoxins. This estimate is based on the specified horsepower of the proposed compressor and a comparison to similar gas-powered compressors in NYS. 

What are the anticipated health impacts for such a facility?

Depending on the frequency and severity of exposure, the health impacts associated with these compounds include respiratory disease, lung disease, asthma, heart failure, premature birth and low birth weight, eye and skin irritation, headaches, sleep disturbances and joint pain.  Children are particularly susceptible.   

A pediatrician, Dr. Curtis Norgaard, estimated the following health outcomes for a similar compressor in New Hampshire:

·      Nitrogen dioxide: Increased respiratory hospitalizations (2%), heart failure (1.7%)

·      Carbon monoxide: Increased premature birth rates (4%), and put women at risk of having low birth weight babies (7%)

·      Sulfur dioxide: Low birth weight (3%), heart failure (2.4%)

·      Particulate matter: Increased fatality from heart and lung disease (5.3%), and new childhood asthma diagnoses (10-12%).


Curtis Nordgaard, MD MSc, Pediatrician. DotHouse Health. “A compressor station in New Hampshire? Analysis of health risks”

Wilma Subra, a chemist and microbiologist, performed health surveys in Louisiana, Texas and Pennsylvania and reported the health impacts on community members living near compressor stations and gas metering stations along gas transmission pipelines.  61% of health impacts recorded were associated with chemicals present in amounts that were in excess of short and long term health screening levels in the air.  The most prevalent conditions in individuals living close to compressors, and the percentages of study participants who reported these symptoms, were:

·      Respiratory Impacts 71%

·      Sinus Problems 58%

·      Throat Irritation 55%

·      Allergies 55%

·      Weakness and Fatigue 55%

·      Eye Irritation 52%

·      Nasal Irritation 48%

·      Joint Pain 45%

·      Muscle Aches & Pains 42%

·      Breathing Difficulties 42%

·      Vision Impairment 42%

·      Severe Headaches 39%

·      Sleep Disturbances 39%

·      Swollen & Painful Joints 39%

90% of individuals living and working within 2-3 miles of compressor stations reported experiencing odor events and health impacts.  

Why aren’t these health impacts considered during the application process?

In the Environmental Assessment (EA) for the Minisink Compressor, the standards for air emissions used modelling rather than direct measurements. Based on the modeling, FERC wrote:

“… the Minisink Compressor Station would not be a major source of air emissions under federal air quality permitting programs. In addition, the total potential emissions from the proposed station would comply with the EPA’s NAAQS [National Ambient Air Quality Standards,] in accordance with the CAA [Clean Air Act] …”

However, data from the Southwest Pennsylvania Environmental Health Project’s (SWPA-EHP) pilot study of the Minisink compressor show the opposite.  The SWPA-EHP pilot project documented health impacts on residents that were not in synch with what FERC, the EPA and state agencies were modeling, and which had led those agencies to conclude during the application process that there would be no health impacts. The symptoms clinicians observed in people living near gas development could be persistent, transient, or intermittent. These variations in symptom presentation are consistent with the changing and episodic nature of exposures. For example, symptom severity related to particulate matter (PM) correlated with the height of PM measurement using a SPECK Particulate Matter monitor 12-hour report.

The reasons for this disconnect between SWPA-EHP’s field observations and the projections of FERC and other agencies may include:

·      FERC uses models and predictions, in other words, conjecture, to arrive at their conclusions.

·      Measurements done by the company or government agencies were based upon sampling and not continuous.

·      They do not measure peaks of exposure.

·      They do not assess the health data adequately.

·      Critical data is not collected because non-disclosure is a condition of compensation for damages.

Aren’t there strict federal environmental regulations in place?

The oil and gas industry has secured exemptions from key provisions of seven major environmental laws: the Safe Drinking Water Act (SDWA); The Clean Air Act (CAA); the Clean Water Act (CWA); the Resource Conservation and Recovery Act (RCRA); the Comprehensive Environmental Response, Compensation and Liability Act (CERCLA); the National Environmental Policy Act (NEPA); and the Toxic Release Inventory of EPCRA (Emergency Planning and Community Right-To-Know Act).  Most critically:

·      The industry’s exemption from the aggregation of small projects under the Clean Air Act means that the cumulative health effects of multiple compressors and pump stations along a pipeline cannot be taken into consideration – each project is evaluated in isolation.

·      Exemptions to the Clean Water Act mean that contaminated run-off from pipeline construction and operations can flow into rivers and streams.

·      Exemptions from CERCLA mean that the oil and gas industry is not held liable for the spill or release of the toxic substances benzene, toluene, ethylbenzene, and xylene (Btex) – substances that are regulated for other industries – and are not held liable for clean-up costs.

·      Exemptions from NEPA, enacted with the Energy Policy Act of 2005, weakened the environmental review and public participation standards of the law in application to the oil and gas industry.

·      Exemptions from the Toxic Release Inventory of EPCRA relieve the oil and gas industry of the requirement to report significant releases of toxic substances, including fugitive emissions, which makes it difficult to analyze health impacts or assign responsibility.