By GASIN Reporter
GASIN pays close attention to the safety of the environment amidst resource exploitation in the Niger Delta. As an expert-based civil society organization exclusively focused on gas, an elaborate desk research into the environmental and health issues associated with gas exploitation has been carried out. Some of the findings highlighting the environmental and common health issues associated with natural gas exploration and processing are herein presented.
These findings are the motivations behind the awareness and enlightenment campaign GASIN carries out in many communities hosting gas facilities in the Niger Delta. It is worrisome to us that the international best practices guiding gas exploitation are not strictly followed and regulated by gas operators and government regulatory agencies respectively, leaving the local people and the environment almost helpless.
Radioactive metals contaminate natural gas. Radon, for instance, is present in natural gas, because natural gas had previously been in contact with underground uranium and thorium-bearing rock and soil which continually release radon. The radon and its progeny remain with the natural gas as it travels through distribution pipes and into homes (ATSDR, 2010). Radium, a potent carcinogen, is also a heavy metal that mixes with natural gas, and also gives off radon gas, accumulates in plants and vegetables and takes 1,600 years to decay; it is known to cause bone, liver and breast cancers (Scientific American, 2009).
Radon is listed as a human carcinogen in the Twelfth Report on Carcinogens published by the National Toxicology Program because it causes lung cancer. Exposure to high levels of radon can cause other lung diseases such as emphysema and thickening of lung tissues whereas simultaneous exposure to radon and cigarette smoking can increase the incidence of lung cancer and lung disease (United States National Library of Medicine, 2012). Gas industry workers, for example, would almost certainly face an increased risk of cancer if they worked in a confined space where radon gas, a leading cause of lung cancer and a derivative of radium, can collect to dangerous levels (Scientific American, 2009).
In addition, radon concentrations have been found to be higher in the natural gas central processing facilities than the wellheads; these high levels are due to pressurizing and concentrating processes that enhance radon gas and its decay products (Al-Masri and Shwiekani, 2008).
In the gas processing facilities, plants that can filter out the radioactive materials are left with a concentrated sludge that has substantially higher radioactivity than the wastewater. Sludge can also collect inside the pipes at well sites, in waste pits and in holding tanks (Scientific American, 2009). Wastewater from natural gas drilling in New York State for instance, has been found to be radioactive, as high as 267 times the limit safe for discharge into the environment and thousands of times the limit safe for people to drink (Scientific American, 2009).
Hazardous materials and wastes
Natural gas processing facilities use and manufacture significant amounts of hazardous materials, including raw materials, intermediate/final products and by-products (WBG, 2007). These include highly toxic liquid effluents and solid wastes that accumulate in the interior surfaces of ethylene glycol regeneration facilities and other processing units within the processing plants. The wastes are dumped off site, leading to serious lethal environmental pollution.
Hazardous air pollutants (HAPs) from natural gas facilities include hydrogen sulfide and certain hydrocarbons such as benzene, a known human carcinogen. Formaldehyde is a HAP found in the exhaust of compressor engines (Ramon and Elizabeth, 2012). Elevated levels of benzene have been detected near some natural gas production sites (Goal, 2008; Coons and Walker, 2008).
In Gas-To-Liquid (GTL) units in natural gas processing facilities, hazardous wastes that are generated include bio-sludge, spent catalysts, spent oil, solvents, and filters (e.g., activated carbon filters and oily sludge from oil water separators), used containers and oily rags, mineral spirits, used sweetening, spent amines for CO2 removal and laboratory wastes (WBG, 2007).
Spent catalysts from GTL production are generated from scheduled replacements in natural gas desulphurization reactors, reforming reactors and furnaces, Fischer-Tropsch synthesis reactors. These spent catalysts may contain zinc, nickel, iron, cobalt, platinum, palladium, and copper, depending on the particular process involved (WBG, 2007). These heavy metals are highly toxic to living organisms including man.
Fugitive emissions in natural gas processing facilities are associated with leaks in tubing; valves, connections, flanges, packings, open-ended lines, floating roof storage tank, pump, and compressor seals; gas conveyance systems, pressure relief valves, tanks or open pits/containments, and loading and unloading operations of hydrocarbons. The main sources and pollutants of concern include Volatile Organic Compound (VOC) emissions from storage tanks during filling and due to tank breathing; floating roof seals in case of floating roof storage tanks; wastewater treatment units and product upgrading units [World Bank Group (WBG), 2007]. These emissions constitute serious environmental pollution.
Polychlorinated biphenyls (PCBs) Pollution
PCBs are a blend of chemical compounds used in a variety of industrial products because of its chemical and thermal stability. In natural gas systems, PCBs are used as a compressor hydraulic/lubricant and a valve sealant (Environmental Protection Agency [EPA], 2004; Woodyard, 2005). Because these applications allow the PCBs to come in contact with the gas, some of the PCBs would occasionally enter the gas stream (Woodyard, 2005).
Leakages, venting or domestic utilization of PCB-contaminated gas leads to PCBs pollution of the environment. PCBs affect the skin, organ development, glands and hormones, liver, immune system and nervous system, and it is also reasonably anticipated to be Human Carcinogens (Agency for Toxic Substances and Disease Registry [ATSDR], 2011).
A natural gas pipeline is a potential fire hazard, especially where they run through communities that do not have sufficient pipeline safety precautions and orientation. Both internal and external corrosion of pipelines result in gas leaks. Thus, a rupture or fracture of a gas transmitting pipeline can lead to serious fire, with the accompanying pollution of the air by carbon dioxide and smoke. Moreover, the hitting of the pipeline by the high speed particles at pipeline bends causes erosion of the pipeline surfaces which eventually results in ruptures, with time. This increases the chances of leakages and consequent explosion. Cases of gas leakages are very common in the Niger Delta.
It has been found that natural gas contains mercury as one of the heavy metal contaminants. Mercury has a combination of health effects, which includes developmental (effects during periods when organs are developing), gastrointestinal (digestive), neurological (nervous system), ocular (eyes) and renal (urinary system or kidneys) (ATSDR, 2011).
Venting and Flaring
Venting and flaring are an important operational and safety measure used in natural gas processing facilities to ensure gas is safely disposed of in the event of an emergency, power or equipment failure, or other plant upset conditions. Unrelated raw materials and by-product combustible gases are also disposed of through venting and flaring (WBG, 2007), which constitute serious air pollution that leads to many health issues. This is made worse by the fact that gas travels wherever the wind takes it, and its effluents spread even wider.
Fire and Explosions
Fire and explosion hazards generated by process operations include the accidental release of Syn-gas (containing carbon monoxide and hydrogen), oxygen, and methanol. High pressure Syn-gas releases may cause “Jet Fires” or give rise to a Vapor Cloud Explosion (VCE), “Fireball,” or “Flash Fire,” depending on the quantity of flammable material involved and the degree or pressure of confinement of the cloud. Hydrogen, methane, and carbon monoxide gases may ignite even in the absence of ignition sources if their temperatures exceed their auto-ignition points of 500°C, 580°C, and 609°C, respectively. Flammable liquid spills may cause “Pool Fires” (WBG, 2007).
Moreover, as natural gas begins to collect in a space where there is a gas leak, it becomes more and more volatile. In the most dangerous situations, a natural gas leak can cause an explosion. An explosion can occur when natural gas reaches 4 to 15 percent in the air. It can be ignited by an open flame or electrical appliance. Lighting a cigarette, turning on a light switch, plugging in or unplugging appliances can create the spark needed to create an explosion in a space with a natural gas leak (Casandra, 2012).
Also, leaks of oxygen-enriched gases from gas separation units can create a fire risk. Oxygen-enriched atmospheres may potentially result in the saturation of materials, hair, and clothing with oxygen, which may burn violently if ignited (WBG, 2007).
Atmospheric emissions from rigs consist mainly of exhausts from diesel engines supplying power to meet rig requirements (drilling, hoisting, electricity, etc.). These emissions may be particulates, oxides of Nitrogen, carbon monoxide, sulfur dioxide and volatile organic compounds (VOCs). Nitrogen oxides and VOCs may combine to form ground level ozone. Impacts would depend upon the amount, duration, location and the meteorological conditions (e.g. wind speed and direction, precipitation and relative humidity). Emissions during this phase would not have a measurable impact on climate change. Sulfur dioxide can lead to corrosion of roofing sheets as a result of fuel burning through combustion; SO2 is released into the atmosphere which when made damp by the weather stays on roof tops thereby eating up the roof so that in France it was estimated that roofs that used to last for 30 years now last for only 4-5 years in worse cases. Similar cases are seen in Niger Delta communities hosting companies with functional gas flare facilities.
Exhaust gas emissions are produced by the combustion of gas or other hydrocarbon fuels in turbines, boilers, compressors, pumps, and other engines for power and heat generation and are a significant source of air emissions from natural gas processing facilities. Incineration of oxygenated byproducts at Gas-To-Liquid (GTL) production facilities also generates CO2 and nitrogen oxides (NOX) emissions (WBG, 2007).
Process wastewater and other wastewaters, which contain dissolved hydrocarbons, oxygenated compounds and other contaminants, are always generated during natural gas processing. This wastewater is normally channeled to a nearby water body (WBG, 2007).
The principal sources of noise in natural gas processing facilities include large rotating machines (e.g. compressors, turbines, pumps, electric motors, air coolers, and fired heaters) etc. During emergency depressurization, high noise levels can be generated due to release of high-pressure gases to flare and/or steam release into the atmosphere (WBG, 2007). Prolonged exposure to high noise levels lead impaired hearing conditions.
NATURAL GAS AND HUMAN HEALTH
Exposure to natural gas through gas leaks can be harmful. It may lead to explosions and pose serious health hazards that are sometimes even fatal. Small gas leaks accumulate over a period of time and add a significant amount of pollutants that stress the immune system and other bodily functions. According to the National Library of Medicine, "If a natural gas leak has occurred and is severe, oxygen can be reduced, causing dizziness, fatigue, nausea, headache, and irregular breathing" (Casandra, 2012; Deyanda, 2012). Gas leaks can cause serious harm to plants, thus affecting the environmental ecosystem as well (Deyanda, 2012). Some common health issues associated with natural gas are highlighted as follow:
One of the major health effects of natural gas leakage (or exposure to methane) is asphyxiation. It is a serious health condition where the body is not able to get sufficient oxygen supply, which may lead to loss of consciousness, brain damage and death. People with high chemical sensitivity are more susceptible to this disease (Deyanda, 2012).
Asthma and Respiratory Illness
Natural gas has been linked to asthma and other respiratory illnesses, especially because it contains, in addition to methane, many toxic impurities including radon and other radioactive materials, BTEX (benzene, toluene, ethylbenzene and xylene), organometallic compounds such as methylmercury, organoarsenic and organolead, mercaptan odorants, nitrogen dioxide, carbon monoxide, fine particulates, polycyclic aromatic hydrocarbons, volatile organic compounds (including formaldehyde), and hundreds of other chemicals (Wimberly, 2000).
Leakages and subsequent combustion of natural gas release large amounts of water vapor, ashes, volatile organic compounds and toxic fumes into the atmosphere. These particulates and substances pass through our respiratory system and enter deep into the lungs and body, bringing about respiratory diseases. Natural gas is lighter than air and therefore rises up, concentrating nearer to the head. Associated symptoms such as pneumonia, nausea, vomiting, irregular breathing, memory loss, fatigue, sinus pain and headache are also reported because of the exposure to natural gas leaks in lower concentrations. Some other adverse effects include flatulence, diarrhea, constipation, depression, itching in genitals and pain in hands and legs (Deyanda, 2012).
Benzene, toluene and xylene are members of the BTEX (Benzene, Toluene, Ethylbenzene and Xylene) released during natural gas processing. These toxic compounds have been found to decrease sperm vitality and sperm motility (GuoBing et al, 2001). Thus, communities located around natural gas processing facilities are potentially exposed to these compounds. Moreover, exposure to carbon disulphide and ethylene glycol ethers has been linked to infertility (Lähdetie, 1995).
Methanethiol (methyl mercaptan) or ethanethiol (ethyl mercaptan) is the odorant that is added by the natural gas companies to detect its leakage. When inhaled in sufficient amounts, ethanethiol causes physiological effects such as dizziness, headache, vomiting, shivering, fever and unconsciousness. Natural gas may also contain several contaminants like PCBs (polychlorinated biphenyl), benzene, toluene and radon (radon is present in natural gas in its original state). We inhale benzene and toluene during gas leaks. They pose serious health threats. PCBs, benzene and radon are carcinogenic (cancer-causing), whereas toluene may cause reproductive harm (Deyanda, 2012).
Cancer and Birth defects
Researchers have found out that residents living ≤ ½ mile from wells are at greater risk for health effects from natural gas processing facilities than are residents living >½ mile from wells. Cumulative cancer risks are 10 in a million and 6 in a million for residents living ≤ ½ mile and >½ mile from wells, respectively, with benzene as the major contributor to the risk. Subchronic exposures to air pollutants during well completion activities present the greatest potential for health effects (McKenzie et al, 2012).
Benzo-a-pyrene occurs naturally in natural gas extracted from the ground. It inhibits the P53 gene and now has a direct correlation to natural gas. It has therefore been listed as one of the chemicals known to cause cancer, birth defects and reproductive harm (Gascape, 2012).
New research suggests the health of newborn babies is adversely affected in areas close to sites undertaking natural gas extraction by way of hydraulic fracturing, or fracking; the method of obtaining natural gas by blasting shale with a solution of water and chemicals (The Epoch Times, 2012).
It is also documented that fetal exposure to high levels of PCBs, which are also used in natural gas processing facilities, cause skin and nail abnormalities (Rogan, 1982).
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