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1: Executive Summary

2: About Oil/Gas Leases

3: Oil & Gas Impacts

4: Bush Admin Rollbacks

5: The Spin on Drilling

6: Hotspot: Roan Plateau, CO

7: Hotspot: Otero Mesa, NM

8: Hotspot: Rocky Mtn Front, MT

9: Hotspot: Powder River Basin, WY

10: Hotspot: Book Cliffs, UT

11: Oil, Gas, Political Cash

12: EWG Recommendations

13: Methodology

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Oil & Gas: Impacts at Every Step of the Way

The process of obtaining oil and gas from federal lands involves more than just drilling. Some of the potential impacts from drilling to wildlife, drinking water, and local communities are documented here, including those from exploration techniques, road construction, the use of heavy machinery, and the use and production of hazardous fluids. In some cases, oil and gas operators can take measures to mitigate environmental impacts — these measures are also discussed below. For a more detailed discussion of these issues, see the Oil and Gas Accountability Project's (OGAP) "Oil and Gas at Your Door: A Landowner's Guide to Oil and Gas Development" (OGAP 2004).


Once potential operators of oil and gas wells have leased land, they can enter the land to explore for oil and gas. The most common exploration technique is "seismic exploration" in which an operator explodes dynamite in a hole drilled several hundred feet in the ground, drops a heavy object from a truck onto a hard surface such as a paved road, or shakes the ground with a mechanism known as a vibrasizer.

Seismic waves from these impacts travel downward and outward and then bounce back at different rates and strengths depending on what underground substances the waves pass through. Oil and gas companies analyze these waves to determine the location of oil and gas deposits (Farmbrough 1996).

Impacts from exploration can be significant. The author, Terry Tempest Williams, recently described a convoy of "thumper trucks" moving through Utah's red rock desert. The giant trucks, with tires as tall as a man, were exploring for oil by lowering huge plates onto the desert, applying 64,000 pounds of pressure and then sending a seismic jolt into the ground to measure the waves as they returned.

"Three other thumper trucks were at work about half a mile ahead," Williams wrote. Behind them was pulverized earth: a 15-foot swath of beaten down and broken junipers, blackbrush, rabbitbrush, squawbush and cliffrose. The delicate desert crust that holds the red sand in place from wind and erosion, known as cryptobiotic soil, was obliterated. Replacing it, in effect, was a newly crushed road. "In January Jayne Belnap, a United States Geological Survey expert on soil damage, submitted an official comment letter to the Bureau of Land Management about the fragility of desert crusts, warning it could take from 50 to 300 years for the dry soil to recover from the damage incurred by heavy equipment" (Williams 2002).

Among other damage, water seepage can result when blasts from dynamite breach the water table. Water seeping from such blast holes has made land so wet that farmers were unable to harvest hay. Plugging these holes from bottom to top can avoid water seepage problems.

Wire pin flags used for surveying can be shredded in the making of hay. The leftover metal bits can kill livestock that eat the feed. Livestock and wildlife can also die after eating ribbons attached to the flags. To prevent such harm, OGAP recommends that operators use of wooden stakes and remove them when exploration is complete (OGAP, I-6).

Exploratory Drilling

After exploration is complete, oil and gas companies will drill exploratory wells to ensure that there is oil and gas on the site in quantities sufficient for economical development.

This stage includes building roads for access to the drilling area, which may require bulldozers, road graders and gravel trucks. The oil or gas company will then clear vegetation from the drilling area and level it. The company may construct a drilling pad out of gravel as well as pits to hold water and other wastes. Next, the company will install the drilling rig that raises and lowers the drill stem and bit along with any associated engines, pumps and equipment.

Impacts in the drilling stage include disturbed land, which can exceed 40 acres per well depending on the length of roads, size of equipment, and other factors (LEERIC). The movement of heavy vehicles and drilling can create continuous noise, often running 24 hours each day, seven days a week. Emissions from diesel engines and turbines that power the drilling equipment can pollute the air with particulates and carbon monoxide (EPA 2000, 38; BLM Draft EIS 2000, 4-51)

The drilling process can generate thousands of gallons per day of drilling waste including "cuttings" (the shards of rock generated by the drill bit) and drilling fluid or "mud" that is used to keep the hole open and the drill bit cool. The cuttings can contain arsenic as well as oil with which the cuttings come into contact during the drilling process. Oil and gas companies use water-based muds most commonly but also use more toxic oil-based muds for certain types of drilling (EPA 2000, 18-19). Drilling operators sometimes place wastes in pits lined with plastic but often discharge cuttings, muds, and other drilling byproducts onto the ground (Beaumont).

Several ways to reduce the impacts from drilling include using lined pits to store waste or shipping waste to a secure disposal facility, using less toxic drilling fluids, and revegetating the drilling pad surface with native grasses (OGAP 2004, I-12).

Completion of Drilling

Oil and gas companies will sometimes employ techniques to improve the flow of oil and gas to the well. One such method is known as hydraulic fracturing or "fracing" (rhymes with "cracking"). Companies use fracing to create fractures in rock or coal formations so that gas or oil can escape. In this method, the companies will pump into the formation a fluid, often one that they have thickened with gelling agents. The formation will crack under the pressure, and then the company will pump in substances called "proppants" to hold the fractures open. Some fracing fluids and proppants include potentially toxic acids and diesel fuel (EPA 2002, Ch.4). The EPA has warned that "the use of diesel fuel in fracturing fluids by some companies introduces the majority of constituents of concern to underground sources of drinking water. Water-based alternatives exist and from an environmental perspective, these water-based products are preferable" (EPA 2002).

Drilling often removes enormous amounts of groundwater. Companies frequently pump out thousands of gallons of water per well, particularly in oil wells and coal bed methane operations (USGS 2004 and EPA 2000, 38-39). The removal of water can create several problems: water may be depleted from nearby aquifers if large quantities of water are pumped out of the ground (Regele and Stark 2000, 3-5); removing water from coal beds creates the potential for underground coal fires; and vast quantities of water that are saline or contaminated with drilling fluids can contaminate soil, surface water and groundwater (OGAP I-48; USGS 2004).

One way to reduce the amount of water and hazardous substances used in drilling is to use a fracing technique that employs sand and carbon dioxide. It is reported that this technique has increased production by two to five times more than water-based fracing (McCallister 2000). Another way to reduce environmental impacts is by so-called "closed loop" drilling in which the solid cuttings are removed from the drilling fluid and the fluid is stored in tanks and reused rather than dumped in a pit as is frequently the case. One contractor in Texas saved $10,000 per well by using "closed loop" drilling due to lower construction, closure and waste management costs (there was no need to build a pit or clean it up). The operator also reduced its liability by eliminating the chance of contamination from a leaking pit (Texas RRC 2004).

Transportation of Oil and Gas

While roads and well pads disturb some land, the construction of pipelines and compressors that are used to transport oil and gas from the well can impact additional acres. Compressors, used to maintain pressure in pipelines for the transportation of natural gas, can produce a tremendous amount of noise that disturbs local landowners (PRBRC 2000).

Abandoning Wells

Some wells are left unplugged or improperly plugged after they have ceased to produce oil or gas or after their operators have abandoned them. Some such wells are abandoned after their operators go bankrupt and have no funds for properly securing the well. Oil, gas and saltwater leaking from improperly plugged wells can contaminate groundwater. Improperly plugged wells can also allow pesticides to leak into groundwater supplies and can pose safety risks to humans and livestock (OGAP I-27, 2004).

State and federal governments should ensure that wells are properly abandoned.


  1. Beaumont and Foster, 1992; Legg, 1994. in Oil - A Life Cycle Analysis of its Health and Environmental Impacts. Edited by Paul R. Epstein and Jesse Selber. The Center for Health and the Global Environment, Harvard Medical School. March, 2002. pp. 9,10. Accessed online on June 29, 2004 at http://www.med.harvard.edu/chge/oil.html.
  2. Bureau of Land Management (BLM EIS). 2000. Draft RMPA/ElS for Federal Fluid Minerals Leasing and Development in Sierra and Otero Counties. 4-51.
  3. Environmental Protection Agency (EPA). October 2000. Profile of the Oil and Gas Extraction Industry. EPA Office of Compliance Sector Notebook Project. EPA/310-R-99-006. pp. 18, 33, 38-40, 52-55. http://www.epa.gov/compliance/resources/publications
  4. Environmental Protection Agency (EPA). August, 2002. DRAFT Evaluation of Impacts to Underground Sources of Drinking Water by Hydraulic Fracturing of Coalbed Methane Reservoirs. EPA 816-D-02-006. Chapters 1, 4. http://www.epa.gov/safewater/uic/cbmstudy/docs.html.
  5. Farmbrough, J. June 1996. Minerals, Surface Rights and Royalty Payments. The Real Estate Center, Texas A&M University. Technical Report 840. p. 5.
  6. Louisiana Energy and Environmental Resource and Information Center (LEERIC). Louisiana State University. Accessed online June 29, 2004 at http://www.leeric.lsu.edu/bgbb/5/drilling.html.
  7. McCallister, Ted. (updated 2002) lmpact of Unconventional Gas Technology in the Annual Energy Outlook 2000. Energy Information Administration, US Department of the Environment. Accessed online July 12, 2004 at http://www.eia.doe.gov/oiaf/analysispaper
  8. Oil and Gas Accountability Project. (OGAP). 2004. Oil and Gas at Your Door: A Landowner's Guide to Oil and Gas Development. Accessed online June 16, 2004 at http://www.ogap.org/.
  9. Powder River Basin Resource Council (PRBRC). Winter 2002/2003. Coalbed Methane Monitor. Accessed online on June 29, 2004 at http://www.powderriverbasin.org/cbm/index.htm.
  10. Regele, S. and Stark, J. Sept. 2000 (Regele and Stark). Coal Bed Methane Gas Development in Montana, Some Biological Issues. Montana Department of Environmental Quality, Industrial and Energy Minerals Bureau. Accessed online on June 29, 2004 at http://www.deq.state.mt.us/CoaIBedMethane
  11. Texas Railroad Commission, Oil and Gas Division, Waste Minimization Case Histories — Drilling Operations (Texas RRC). Accessed online July 12, 2004 at http://www.rrc.state.tx.us./divisions/og/key-programs
  12. U.S. Geological Survey (USGS). 2004. Environmental Impacts Associated with Disposal of Saline During Petroleum Production - Osage-Skiatook Petroleum Environmental Research Project. Accessed online on June 29, 2004 at http://toxics.usgs.gov/sites/ph20_page.html.
  13. Williams, Terry Tempest. Chewing Up a Fragile Land. The New York Times. February 21, 2002, pg. 23.

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