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Groundwater may also be affected by the thousands of wells in Texas drilled for water or for oil and gas
exploration. When improperly drilled or cased, or when the casing has corroded, old oil, gas, and water wells serve as conduits for contamination of the aquifers below. Improperly completed
and abandoned water wells may allow direct access from the surface to groundwater for contaminants such as pesticides, or they may facilitate the comingling of groundwater from one aquifer to
another. Additionally, they can be a safety hazard to humans and livestock.
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COUNTIES WITH GROUNDWATER CONTAMINATION
FROM OIL AND GAS ACTIVITIES, 2002
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Source: Texas Natural Resource Conservation Commission, Joint
Groundwater Monitoring and Contamination Report, 1997 (June 1998), Figure 12.
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According to TWDB estimates, more than 800,000 water wells were drilled last century
in Texas. The TWDB estimates that about 20,000 new wells are drilled each year, most of which are not properly inventoried.*
Currently, the TWDB maintains an ambient groundwater monitoring database that contains information from over 51,000 water wells, but it has information on more than
50,000 other wells. Still, there is little information on potentially hundreds of thousands of presently operating and abandoned water wells. All new wells must
meet specific casing and construction standards, and abandoned wells must be plugged. This plugging activity is overseen by the Water Well Drillers/Pump Installer Section
which in 1997 was transferred from the TCEQ to the Texas Department of Licensing and Regulation.* About 150 wells per month are
plugged by individual landowners and reported to the Water Well Drillers.* In 2002, the Water
Well Drillers Section conducted 519 investigations, and located 32 abandoned wells, leading to notification, further investigations and in some cases enforcement to plug the water wells.
In addition to water wells, an estimated 1.5 million holes were drilled last century for oil- and gas-related activities.* Currently, 266,820 active oil wells and 88,048 active gas wells across the state are registered with the Railroad
Commission, about 88,000 of which are not currently producing.* Commission records indicate that between FY 1992
and FY 2002, operators of oil and gas wells voluntarly plugged some 90,000 wells, while some 24,449 abandoned wells remain inactive and in violation of the commission's plugging rule.*
Abandoned oil wells are channels for the upward movement of brine—salt water often found in oil-bearing zones—and
they are paths to contamination by oil and gas, drilling fluids, and other contaminants. Salt water from abandoned oil wells has already polluted the upper portions of the Colorado River.* These wells must be plugged to prevent the
contamination of aquifers by salt water and oil wastes. To address the large number of unplugged wells, the Texas
legislature in 1983 created a new Abandoned Well Plugging Fund, which was supported by a $100 per well drilling
permit fee, penalties, and other sources of funds. In 1991, due to falling oil production which jeapordized the program,
the Texas Legislature enacted SB 1103, which created the Oil Field Cleanup Fund, and authorized new funding sources.
The Oil Field Cleanup Fund can be used for a variety of environmental purposes including plugging and cleaning up
abandoned leases, pits and oil fields. Further changes enacted in 1999 and 2001 helped increase the drilling fees,
penalties, regulatory fees and interest which support the program. In fact, changes made in 2001 increased the amount
that could be spent annually from $10 million to $20 million, providing there is sufficient revenue. For example, in FY
2002, total revenues were about $16.8 million and total expenditures were $18.3 million, a large portion of which ($6.9
million) was used to plug some 1,400 abandoned wells. Between FY 92 and FY 2002, the Railroad Commission plugged 15,306 abandoned wells .*
Other Oil and Gas Industry Impacts
The EPA estimates that about one million tons of hazardous waste is produced each year in American oil fields.* The disposal of these wastes has the potential to affect groundwater. Until 1969, when the Railroad Commission adopted its
no pit rule—also known as Statewide Rule 8—oil companies typically disposed of salt water and chemicals in open pits,
creeks, and roads. The chemicals used during the oil-well drilling process and disposed of in these pits include such highly toxic elements as barium, arsenic, and cadmium.
Today, the storage and disposal of major oil and gas wastes requires a permit or authorization by rule. Statewide Rule
8 identifies three types of oil-field pits: prohibited pits, authorized pits, and pits authorized through permit. Authorized
activities include land farming, where toxic materials are mixed with soils; burial; road-spreading; commercial hauling,
treatment, and disposal; and the use of pits such as reserve pits, fresh mining water pits, and others. Other pits such
as saltwater disposal pits, brine pits, drilling-fluid storage and disposal pits, and gas-plant evaporation and retention pits, require a permit from the Railroad Commission.* There are currently 28 land-farming facilities permitted for
disposal of oil and gas waste and 4,220 pits permitted for storage or disposal of such wastes or the retention of brine .* However, in 2002, only 55 sites regulated by Statewide Rule 8 required groundwater monitoring.*
The Railroad Commission reported 225 cases of groundwater contamination from oil and gas activities in 81 different
counties, including 26 new cases in 2002. These cases included facilities covered under Rule 8, both those requiring
permits and those which do not require them, as well as illegal waste sites identified through a complaint or investigation.* Under the Oil Field Cleanup Fund, many of the older contaminated sites can use state monies to help
clean-up these and other sites. For example, during FY 2002, some 1,629 abandoned oilfield sites were identified as
candidates for state-managed remediation, and 355 cleanup or investigation activities were conducted. Between FY 92
and FY 2002, the Railroad Commission of Texas used the Oil Field Cleanup Fund to clean up, assess or investigate over
2,100 abandoned oilfield sites, many of which involved groundwater contamination *. Finally, the Railroad Commission
of Texas also runs a Operator Cleanup Program funded by the responsible operator. The program helps coordinate the
assessment and clean-up of environmentally sensitive sites. Often, the frequent mergers, acquisitions and divestitures
of oil field properties lead the new owners to assess and remediate newly acquired property under the guidance of the
Railroad Commission. Between 235 and 625 sites a year are have been assessed through this program over the last five years *
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