Almanac Table of Contents | Chapter Nine Table of Contents | TEC Home Page

NEXT PAGE * PREVIOUS PAGE Go to page 1*2*3*4*5*6*7*Notes


Texas Environmental Almanac, Chapter 9, Industrial Waste, Page 5
Reducing Hazardous Characteristics of Waste: Burning

Incineration is preferred to landfilling and underground injection in the state's hazardous waste management hierarchy. It reduces and may, in some cases, eliminate hazardous characteristics of waste. In the case of waste-to-energy facilities, it may also provide energy for use in other production processes. However, the burning of hazardous waste in incinerators, boilers and industrial furnaces (BIFS) and in cement kilns - which burn waste to produce cement - increases the amount of toxics released to the air (see Air chapter). In addition, the ash produced by burning hazardous waste may still be a threat to human health and the environment because it may contain such compounds as lead, uranium and arsenic. Finally, the variety of waste streams received at commercial incineration facilities makes it harder to control the burning process, leading to problems with explosions and toxic plumes.(86) For these reasons, a number of citizen-based and environmental groups in Texas have been vocally opposed to both the current operation of hazardous waste burning facilities as well as permitting additional facilities.

In the past, some facilities mixed hazardous waste or used oil with fuel to augment the heating value of fuels and reduce waste disposal costs, while at the same time avoiding regulation of waste disposal.(87) Until 1986, some utilities, industries, commercial facilities, schools, government institutions and apartment and home owners across the country used hazardous waste and used oil for energy recovery purposes.(88) Today, non-industrial facilities - homes, apartments, schools - are not allowed to burn hazardous waste or used oils containing toxics. Industrial facilities using hazardous waste or used oil must comply with certain standards and register with both the EPA and the state.(89)

In 1991, more than one million tons of hazardous waste were incinerated or burned for energy or thermal recovery at on-site boilers and industrial furnaces and industrial facilities in Texas.(90) An additional 200,000 tons were burned at commercial facilities. There is an increasing reliance on the burning of waste; 28 percent of Texas-generated hazardous waste processed and treated off-site was burned.(91)

Incineration has increased in Texas in large part because of imports of hazardous waste from out-of-state facilities as well as an increase in commercial capacity at cement kilns.(92) There has also been an increase in demand as a result of the federal land disposal rules, which require treatment of hazardous waste before land disposal. As land disposal has decreased, incineration and deep-well injection of waste have increased. Hazardous waste imported from out-of-state industries for incineration by Texas facilities increased from 31,000 to nearly 65,000 tons between 1989 and 1991.(93)

There are currently two commercial cement kilns that use hazardous waste fuels operating in Midlothian, in Ellis County, as well as 32 permitted hazardous waste incineration facilities throughout the state.

Despite their similarities, cement kilns currently do not have to meet the same standards as commercial waste incinerators.(94) Cement kilns are currently operating under interim regulations which permit them to burn liquid hazardous waste in proximity to populations without the same safety and monitoring standards as commercial incinerators. For example, the plants in Midlothian are located upwind of population centers and near prime agricultural areas. A state task force has recommended applying the same standards to all commercial facilities, including cement kilns, which burn hazardous waste.(95)

Incinerator and cement kiln operators are facing new environmental hurdles which will make their operations more costly. First, the 1990 Federal Clean Air Act is requiring these operators to install costly pollution control equipment to bring toxic air emissions into compliance (see Air chapter).

Second, in 1994, the U.S. Supreme Court ruled that incinerator ash - what remains after either industrial or municipal waste is burned - must be tested to determine if it's hazardous. Incinerator ash can contain some amounts of toxic metals such as lead, arsenic and cadmium. Previously, incinerator ash resulting from the burning of waste at hazardous waste incinerators was defined as hazardous waste, while ash that resulted from municipal solid waste incinerators or cement kiln incinerators did not have to be managed as hazardous waste. Now, all ash found to be hazardous will have to be managed as hazardous waste. The ruling will prevent the current practice of disposing of incinerator ash from the cement kiln industry in quarries. Costs could increase significantly for both municipal waste burners and cement kilns using hazardous waste fuels (see Municipal Waste chapter for more details).(96)


Pie of Hazardous Waste Burned

TOTAL: 1,273,500 TONS

Exports to incinerators out-of-state: 54,500.
Exports to cement kilns out-of-state: 24,200.

Source: Texas Water Commission, Trends in Texas Hazardous Waste Management (Austin: TWC, July 1993), Table 1 and 4.

Underground Injection of Hazardous Waste

The state's fifth-preferred method of managing hazardous waste is disposal in underground injection wells. The disposal of waste in deep geological formations is controversial. Texas officials believe injection wells, when operated correctly, are safe; however, many environmental groups are concerned about the heavy reliance on this technology, particularly the commercial facilities which must manage a wide variety of hazardous waste. Texas injects more liquid hazardous waste underground than any other state.(97)

In the 1930s, oil and gas exploration and production companies began injecting saltwater by-products back into the oil-producing underground strata. The first manufacturing industry to use this same technique to inject industrial hazardous waste underground in Texas was DuPont, which began a waste injection operation in 1953. Most underground injection wells in Texas inject the waste into oil-producing formations.(98)

The 1984 amendments to RCRA prohibited land disposal, including underground injection, of certain types of hazardous waste without pre-treatment. However, if an operator of the injection well can prove the waste will not migrate from the injection zone for 10,000 years, the company can inject hazardous waste into wells without pre-treatment.

Texas regulates the injection of hazardous waste through permits. About 200 permits to operate injection wells disposing of hazardous or non-hazardous waste have been granted in Texas since 1961; 117 of these wells are currently permitted.(99) Most are located in the coastal area and dispose of waste associated with the petrochemical industry; nine of these 117 are commercial facilities.

In 1991, almost 15 million tons of hazardous waste - about 11 percent of all hazardous waste generated - were injected underground in Texas, mostly at on-site facilities owned by companies.(100) In addition, about 12,500 injection wells used for oil and gas waste are currently permitted by the Railroad Commission of Texas to inject millions of tons of saltwater and other waste underground (see Water Quality chapter for a full discussion).(101)

Experts and local state officials agree that waste disposal through properly constructed and operated injection wells is safer and less likely to contaminate surface water or potable groundwater than are landfills and other forms of land treatment.(102) For example, injection of hazardous waste into aquifers that serve or could serve as groundwater supplies for communities is not allowed. However, there are several pathways by which waste injected underground could contaminate water resources:(103)

Because the areas in which deep well injection of hazardous waste is practiced in Texas are precisely those areas with a long history of oil and gas production, there are many possible routes for vertical migration of hazardous waste to the surface. State and federal regulations require those seeking to inject industrial and hazardous waste to survey existing wells within their injection area. Still, the possibility exists that old oil and gas wells may not be located or were not adequately plugged, or that migration could occur outside of the injection zone.

In Texas, the only confirmed case where injected hazardous waste contaminated underground drinking water occurred near Beaumont, Texas in 1975 before more stringent well design standards were enacted.(106) Soil contamination has also resulted from an industrial injection operation when gas apparently formed within the well, causing the waste to "blow out," spreading waste into the air and over the land.(107) Spills at the surface during the handling of the waste prior to injection can also contaminate soils and groundwater prior to injection and have occurred in Texas.

More likely is contamination resulting from the injection of saltwater and other oil and gas production waste. Injectors of these kinds of waste are regulated by the Railroad Commission of Texas, rather than the TNRCC and EPA (see the Water Quality chapter for a more complete description of oil and gas waste). There have been dozens of recorded cases of contamination from injection of saltwater during oil and gas production in Texas. In 1993, for example, there were two cases of oil and gas saltwater waste from injection wells contaminating groundwater.(108)

Acidic chemicals such as sulfuric acid and nitric acid are commonly injected in Texas. Opponents of injection wells have argued that these acidic chemicals have the potential to eat away formations and wells and migrate upward to contaminate groundwater.

Chemical Waste Management Corpus Christi, Nueces
Malone Service Company Texas City, Galveston
Malone Service CompanyTexas City, Galveston
MerichemHouston, Harris
Odessa InjectionOdessa, Ector
Empak Houston, Harris
Chemical Waste Port Arthur, Harris
Disposal Systems Inc.Deer Park, Harris
Gibraltar ChemicalKilgore, Smith
Source: Texas Natural Resource Conservation Commission, "Class 1 Injection Well Permits," (Austin: TNRCC, December 1993).

Nitric Acid16,097,151
Ammonium Nitrate15,578,708
Sulfuric Acid11,291,286
Ethylene Glycol5,643,487
Source: Toxic Release Inventory Program, Office of Pollution Prevention, Texas Natural Resource Conservation Commission.


The TNRCC emphasizes prevention of leaks rather than after-the-fact groundwater monitoring to assure that no leaks have ocurred in hazardous waste wells. In most cases, no groundwater monitoring is required for hazardous waste injection wells. Instead, operators of industrial hazardous waste injection wells are required to perform an annual mechanical integrity test of the well casing. A space between the tubing in which the waste is injected and a second casing is filled with a pressurized anti-corrosive fluid. Since the pressure of the fluid within the well is known, any drop in pressure would indicate a leak in either the tubing or casing.

The usefulness of monitoring wells to detect leakages is hotly debated. There have been cases where groundwater monitoring wells have detected contamination above an injection zone that was not identified by monitoring the pressure within the injection well itself.(104) In addition, environmental groups are concerned that hazardous waste could migrate beyond the injection zones over the long-term, a problem that could only be detected by groundwater monitoring.(105)

Landfilling Hazardous Waste in Texas

At the bottom of the TNRCC's hierarchy of hazardous waste management methods is land disposal, be it landfills, surface impoundment, land treatment units or waste piles. Landfills are controversial for a simple reason: past and present experience has shown that such facilities can eventually leak hazardous materials which can contaminate both the nearby soil and surface and groundwater.(109)

For example, in 1993, the Industrial and Hazardous Waste Division of the TNRCC reported that, between 1989 and 1993, 456 different hazardous waste land disposal sites had contaminated groundwater with either hazardous or other industrial contaminants.(110) The vast majority of these contamination cases occurred at industrial facilities along the Gulf of Mexico.(111)

Texas does not utilize landfills for its hazardous waste as much as some states. Less than 1 percent of hazardous waste managed on-site, and only 18 percent of Texas-generated hazardous waste disposed of off-site at commercial facilities was managed at landfills or other land disposal facilities.(112) There is currently only one commercial landfill receiving hazardous waste in Texas, although another has been permitted recently.(113) About 80 percent of Texas-generated waste which was landfilled went to other states.(114) In addition, 398,000 tons of Class 1 non-hazardous industrial waste were landfilled in Texas and in other states in 1991.(115) These non-hazardous waste included asbestos materials, contaminated soils from abandoned waste sites and PCB-contaminated materials.

New land-disposal restrictions have prevented some types of waste from being disposed of in landfills, further decreasing the demand for this technology.(116) In addition, clean-up of abandoned hazardous waste sites under the Superfund program is now emphasizing clean-up of contaminated soils on-site rather than shipping them off-site, which also has reduced the amount of waste landfilled.(117) Finally, increasing land disposal costs because of RCRA regulations, as well as public opposition and lawsuits over the health impacts of toxic waste dumping, have shifted waste management strategies away from land disposal.

Despite more stringent regulations and permitting requirements, not all disposal of industrial waste into landfills or surface impoundments is closely monitored or requires a permit (see box). For example, industrial facilities do not need a permit to dispose of Class I non-hazardous waste at the facility where it is produced. Thus, most on-site facilities that manage non-hazardous industrial waste do not meet the same strict standards as do facilities which manage hazardous waste or even municipal waste landfills.(118) Yet much Class I waste, including oil and gas waste from exploration and materials containing asbestos and low levels of PCBs, is toxic and potentially dangerous to human health and the environment.

Commercial waste management facilities are more highly regulated and more of a concern to state officials than on-site landfills. While managers of on-site waste management facilities are extremely familiar with their facility's waste stream, commercial facilities receive waste from tens and sometimes hundreds of industries. Thus, the potential for comingling of different waste streams that react, explode or ignite is much higher. Treatment or disposal of this mixed waste can be much more difficult.(119)


Landfills are disposal facilities where hazardous and other solid waste are placed into the land. Landfills designed according to RCRA rules must contain systems to collect contaminated surface water run-off as well as synthetic liners below and around the landfill.

Surface Impoundments are depressions or diked areas where solid waste can be stored, disposed of or treated. Pits, ponds, lagoons and basins are all forms of surface impoundments.

Waste Piles are accumulations of solid waste, sometimes used as disposal sites and sometimes as storage facilities.

Land Treatment is a disposal process in which solid waste is applied on top of or mixed into soil. Land application or land farming facilities are examples of land treatment.

Source: Environmental Protection Agency, Solving the Hazardous Waste Problem: EPA's RCRA Program (Washington, DC: EPA, November 1986).


All facilities which generate hazardous waste are subject to regulations in the State of Texas such as proper registration, labeling, suitable containers and disposal. However, the following types of facilities and processes are usually exempt from hazardous waste permitting requirements, as regulated in Texas:

  • Transfer facilities.

  • Generators which store, treat or dispose of non-hazardous waste, including Class 1 indus-trial waste, on-site.

  • Generators which store hazardous waste in tanks, chip-pads and/or containers for less than 90 days.

  • Small quantity generators that produce less than 1,000 kilograms of hazardous waste a month, provided that no more than 6,000 kilograms are stored for more than 180 days and only 1 kilogram or less per month is "acutely" hazardous.

  • Facilities which treat their waste in units directly connected to an industrial production process, where waste streams are never released into the environment.

  • Some wastewater treatment units, including municipal wastewater treatment facilities and industrial wastewater facilities regulated by the Federal Clean Water Act.

  • Some recycling operations on a case-by-case basis. Only the recycling process itself is exempt.

  • Farmers disposing of pesticides.

  • Clean up of Superfund Sites.

  • Emergency response clean-up.
Source: Texas Natural Resource Conservation Commission, Industrial and Hazardous Waste Division


Controversial plans to locate hazardous and radioactive waste facilities near the border have generated opposition from a new source: Mexico. Mexico is concerned that such facilities could contaminate both the Rio Grande which divides Texas from Mexico, as well as underground aquifers that traverse both sides of the border.

For example, a proposal to build a 600-acre hazardous waste and PCB landfill near Dryden, about 15 miles from the border, was opposed by the City of Del Rio, the U.S. National Park Service, the adjacent Mexican state of Coahuila and many others. Chemical Waste Management eventually withdrew its permit application after the executive director of the TNRCC and the Environmental Protection Agency concluded that the company had failed to demonstrate that it could adequately monitor groundwater underneath the proposed site.

The Federal Government of Mexico sent several diplomatic notes to the U.S. State Department protesting this landfill and a second for radioactive materials proposed by Texcor near Brackettville. Mexico cited Article 2 of the La Paz Agreement - an environmental agreement signed by the U.S. and Mexico in 1983. Both governments agreed to protect a strip 62 miles wide on each side of the border from environmental degradation. The TNRCC rejected the Texcor landfill application in 1993.

Texas Environmental Almanac, Chapter 9, Industrial Waste, Page 5

Almanac Table of Contents | Chapter Nine Table of Contents | TEC Home Page

NEXT PAGE * PREVIOUS PAGE Go to page 1*2*3*4*5*6*7*Notes


Please send questions, comments, or problems with this page to