Oil and gas fields are areas where oil and natural gas have accumulated under the land’s surface. Oil and gas fields can also be offshore in lakes and oceans. Oil and gas operations drill in these fields to extract oil and gas for sources of energy.

Oil and gas operations pose many health, environmental, and safety concerns. Health concerns at oil and gas fields include air emissions of toxic chemicals, drilling waste, radioactive waste, and contaminated water produced by drilling operations.

Oil and gas production can emit hazardous air pollutants, including benzene, toluene, and xylenes. These activities can emit carbon dioxide and methane, which are greenhouse gases that contribute to global warming and climate change.

Operations at oil and gas fields can also emit nitrogen oxides, volatile organic compounds, carbon monoxide, sulfur dioxide, and particulate matter.

Air emissions can come from several sources at oil and gas fields. Sources include equipment engines, drilling rigs, pumpjacks, boilers, heaters, generators, combustion flares, storage tanks, injection pumps, dehydrators, vehicles, and oil and gas skimmers.

One of the major sources of air emissions at gas fields are compressor stations that move natural gas through pipelines and gas processing plants.

Oil and gas field activities produce drilling waste, which contains drilling mud, rock waste, and drilling fluids. Wastes include tank bottoms, which are liquids that collect in the bottom of storage tanks and other production equipment. Other wastes are fluids from treatment and stimulation activities, oily soil and dirty rags, sand, pit and sump waste, and waste from cleaning pipelines.

The underground rock and sediments that hold oil and gas deposits contain naturally occurring radioactive materials, including radium, uranium, and thorium. Radium decays to produce radon, an invisible and odorless radioactive gas. Oil and gas production can leave behind radioactive waste that can settle inside pipes, sludge, equipment, evaporation ponds, waste water, and drilling mud. 

During drilling, a mixture of oil, gas, and underground formation water is pumped to the surface. When the water is separated from the oil and gas, it is called produced water.

Produced water can contain salt, oil, grease, chemicals used in drilling, and naturally occurring radioactive material. It is the largest volume waste from oil and gas production. Produced water in the past was disposed of in evaporation ponds, but is now generally reinjected into deep wells or discharged into non-potable coastal waters. An estimated 35 percent of produced water requires disposal because it cannot be recycled. Past disposal practices and accidental releases of produced water could contaminate groundwater.

Health and safety concerns at oil and gas fields include possible exposure to hydrogen sulfide, a poisonous and flammable gas that occurs naturally in oil and gas. It is an extreme health hazard because it can be fatal or harmful if inhaled. Hydrogen sulfide occurs in many areas marked with warning signs, but can be present in unidentified spaces.

Other safety concerns at oil and gas fields are open waste pits, abandoned wells, drilling equipment, cleaning and pumping activities, fires, explosions, and confined spaces where gases can accumulate.

A major environmental concern is natural gas flaring, which is the process of burning off gas during oil production. Gas flaring emits millions of tons of carbon dioxide each year. Other environmental concerns are damage to land and habitat, leakage of drilling fluids, and fires.

Oil and gas can be extracted through a process called hydraulic fracturing or fracking. It injects water, sand, and chemicals into deep underground rock formations.

Chemicals used in fracturing include benzene, toluene, diesel, lead, ethylene glycol, ethylene oxide, formaldehyde, methanol, and xylene.

Fracturing chemicals may contaminate surface water, groundwater, and aquifers that are sources of drinking water. Chemicals may also be released in spills or leaks from fracturing equipment.

Oil and gas fields can also be offshore in oceans and lakes. Fires and explosions on offshore drilling rigs are a concern as they can lead to oil spills in the water. This was the case in the Deepwater Horizon oil spill of 2010 in the Gulf of Mexico.

Six states in the Southwest are among the top 11 states for oil and gas production: California, Colorado, New Mexico, Oklahoma, Texas, and Utah. Navajo Nation lands in the Southwest include an estimated 1,572 oil and gas wells.

This description is based on the information found in the Web links listed with this topic.

Web Links from MedlinePlus (National Library of Medicine)
Radon

More Links
An Assessment of the Environmental Implications of Oil and Gas Production: A Regional Case Study (Environmental Protection Agency) (PDF — 2.24 MB)
Global Gas Flaring Reduction Partnership (World Bank Group)
Natural Gas Extraction - Hydraulic Fracturing (Environmental Protection Agency)
Oil and Gas Production Wastes (Environmental Protection Agency)
Oil and Gas Well Drilling and Servicing eTool (Occupational Safety and Health Administration)
Oil and Natural Gas Production (Environmental Protection Agency)
Radioactive Wastes from Oil and Gas Drilling (Environmental Protection Agency)

Chemicals in Oil and Gas Fields
Are these chemicals in MY community?
Benzene
Carbon Dioxide
Carbon Monoxide
Crude Oil
Diesel
Ethylene Glycol
Formaldehyde
Lead
Methane
Methanol
Natural Gas
Nitrogen Oxides
Particulate Matter
Radon
Sulfur Dioxide
Toluene
Volatile Organic Compounds (VOCs)

Last Updated: November 14, 2012