For more information about the project, additional copies of this report, or for tables not included in the online version:

The following additional factors were addressed in the paper on Hazardous Waste Generation and Disposal Activities: Public Awareness, Economy, Land Use and Growth.

ISSUE: HAZARDOUS WASTE GENERATION AND DISPOSAL

The issue of risk of hazardous waste generation and disposal is primarily an issue of potential risk versus actual risk. Because the risks and actual instances of contamination of the environment and threats to human health were demonstrated in the decades of the 1960's and 1970's, a very large and comprehensive body of regulations were developed to ensure that this risk was brought under control and managed adequately. The centerpiece of this regulatory body, the Resource and Conservation Recovery Act (RCRA), was enacted by the United States Congress in 1980 to form a "cradle-to-grave" management system for hazardous wastes. RCRA regulates any form of hazardous waste management, including conditions of generation, storage, treatment and disposal, and transportation of hazardous wastes. It also specifies conditions under which hazardous wastes may be recycled or re-used. Because of the stringency of these requirements, very little hazardous waste or hazardous waste constituents escape proper management techniques.

The scope of this paper is very narrowly confined to the risks to the general population and the environment from the generation of hazardous wastes, and its subsequent treatment or disposal. Other papers will address spills or releases of hazardous materials and wastes, and releases from facilities that manage such unique chemical and biological compounds as nerve agent and biological warfare materials.

What is meant by the term "hazardous waste"? RCRA defines hazardous wastes as either having one of several potentially harmful properties or "characteristics", or being on a list of process wastes or substances that were designated as hazardous because of their nature. These wastes can possess corrosive, flammable or reactive characteristics, or they can be designated by placement on a list of process wastes and specific chemical wastes. Box 1 provides a more complete definition of the term "hazardous waste".

The term hazardous waste "disposal" is taken to include forms of hazardous waste management that either alter the waste to remove its hazardous characteristics, destroy the waste or remove it from the environment into an engineered landfill. The first two of these three practices are also termed "treatment".

There are approximately 1500 businesses in Utah that generate hazardous waste. Cumulatively, they generated approximately 3.5 million tons of hazardous wastes in 1991. Their generation rate ranged from less than 100 kg (about 220 lbs) per month to more than 1000 kg (about 2200 lbs) per month. The majority of hazardous waste generators fall into the smaller generation categories. Table I provides a summary of the hazardous waste generators in Utah.

The largest quantities of hazardous waste are generated by 125 facilities in Utah who are termed "Large Quantity Generators". Because of the large quantities of waste they generate and manage, they are the most tightly regulated. They must have detailed plans and procedures implemented, including employee training plans, health and safety plans and contingency plans. They must also report their hazardous waste management activities on a biennial basis to the Utah Division of Solid and Hazardous Waste (DSHW) and the United States Environmental Protection Agency (EPA). These facilities are also inspected at least once every two years by the DSHW. The industries that are most commonly large quantity generators are metal manufacturing, transportation and utility, and defense and electronics manufacturing industries. In 1991, 116 Utah large quantity generators generated about 3.4 million tons of RCRA hazardous waste comprised of 353 different waste code combinations. Six waste streams categorized as corrosive; corrosive with toxic levels of several metals; corrosive with toxic levels of lead; having toxic levels of cadmium and chromium; benzene; and halogenated and non-halogenated solvents comprised 93% of the total waste generated. The majority of the hazardous waste generated (98%) was categorized as inorganic liquids. Surface preparation and refinishing operations, pollution control or waste treatment processes, and cleaning and degreasing operations constituted 85% of the hazardous waste sources. A large majority of these wastes-- approximately 1.8 million tons-- were in the form of wastewaters that were neutralized as they were generated and then sent to publicly operated wastewater treatment plants.

There are approximately 800 facilities in Utah presently notified as "Small Quantity Generators" (SQGs), meaning they may generate between 100 and 1000 kg (approximately 220-2,200 lbs) of hazardous waste per month. They are subject to a less comprehensive set of regulations concerning waste management, personnel training and emergency preparedness. They are not required to report their waste generation and management practices under the Biennial Reporting System. The businesses and industries that have the largest percentage of small quantity generators are machinery and electronics manufacturing, automotive dealers, auto body repair shops and dry cleaners.

There are approximately 300 businesses and facilities that have notified as "Very Small Quantity Generators" (VSQGs), meaning they generate less than 100 kg (approx 220 lbs) of hazardous waste per month. However, there are very many other facilities that may generate small quantities of hazardous waste who have not notified; the actual number of very small quantity generators may be closer to 500. This is because this group is conditionally exempt from regulations, and is not required to notify. However, these facilities may have notified in order to dispose of hazardous wastes at authorized treatment, storage and disposal facilities (TSDs), or in order for hazardous waste transport facilities to transport their waste to TSDs. The largest categories of notified VSQGs are small dry-cleaners, auto repair shops and educational institutions.

TABLE I

* Numbers of small quantity and very small quantity generators are estimated.

** Quantity generated by large quantity generators based on information reported in 1991 Biennial Reporting cycle. Quantity generated by small and very small quantity generators estimated based on maximum generation rates.

Because SQGs and VSQGs are not required to provide any information to state or federal regulators, there is less certainty about the hazardous waste management practices of this group in terms of aggregate quantities of waste produced or types of wastes produced. The businesses these generators are in tend to produce a limited number of types of wastes. Chlorinated solvents are the most common waste stream produced by these businesses, most of which are small machinery and electronics manufacturers, automotive dealers, auto body repair shops and dry cleaners.

Facilities that generate hazardous waste are located throughout the state. The larger quantity generators tend to be clustered in the more industrialized areas of the state in northern Utah. The much larger number of small and very small quantity generators are associated with service industries, and as such are located in the urbanized areas of the state. In the past, this has meant primarily northern Utah, but as urban areas grow, particularly in southwestern Utah, it is expected that the number of generators will increase in these areas.

Many facilities that generate hazardous waste also store it for a certain period of time on their property before disposing of it. This time period may be as long as 90 days (some facilities are permitted to store hazardous wastes for longer periods of time, under a certain set of conditions), and are then sent to hazardous waste treatment and disposal facilities either in Utah or other states.

The risks specifically associated with spills and releases of hazardous wastes are addressed in Utah's Comparative Risk Assessment as a separate issue: Spills and Releases of Hazardous Materials and Wastes. However, the clean-up of hazardous waste spills and releases is a significant contributor to the generation of hazardous waste in Utah, and is a significant part of hazardous waste management for many facilities that generate hazardous waste.

The major risk associated with the generation of hazardous waste is that of the inadvertent release of hazardous wastes to soil, surface water or groundwater through improper management methods. Many older manufacturing or processing sites have areas on their properties in which old management practices are responsible for areas of contamination. Contamination is also occurring at operating facilities at which wastes are improperly managed, either through ignorance or to avoid the costs and administrative responsibility of proper management. It is not known how many spill or release sites are present in Utah. Information on the sites that are known of will be presented in the Spills and Releases issue discussion. However, it is possible to get a picture of units that are typically involved in the release of hazardous wastes and the contaminants and pathways most frequently involved by examining records of site clean-ups that have been overseen by the Division of Solid and Hazardous Waste. These are sites at which hazardous waste materials have been released, and were discovered during investigations required by hazardous waste management permits, or upon discovery of these releases during excavation of underground storage tanks, construction of new facilities, or environmental assessments conducted pursuant to real estate transactions. A sample of sites is summarized in Table II.

As can be seen from Table II, chlorinated solvents are most frequently involved in hazardous waste releases, and underground storage tanks contaminated with hazardous wastes (usually chlorinated solvents) are the most frequently cited unit which has resulted in a release. It should be pointed out that these units have usually been discovered in the process of removal of old tanks for replacement or closure. The frequency of clean-ups associated with these units is expected to gradually decrease. As can also be seen from Table II, hazardous waste clean-up sites occur more frequently in the more industrialized counties in the state (Salt Lake County may be over-represented due to its proximity to state regulatory offices).

TABLE II

The treatment and disposal of hazardous waste, particularly wastes brought in from other states, is a major public concern in Utah. There are questions about the safety or risk of the disposal methods, transportation of the wastes into, out of, or through the state, and about the concept of being a "dumping ground" for the nation's wastes. The scope of this paper deals primarily with the health concerns surrounding Utah's hazardous waste disposal facilities, but will also attempt to identify some of the factors that have been voiced as concerns regarding "quality of life" in the state.

TABLE III

There are currently three facilities in operation in Utah that accept off-site hazardous waste as a commercial operation, with a fourth currently in the start-up phase. Table III provides some details on these facilities. Two of these facilities are hazardous waste landfills; one landfill accepts "mixed" hazardous wastes, that is, wastes that are both hazardous and contaminated with low levels of radioactive isotopes (this activity is discussed further in the paper on Low Level Radiation Disposal Activities). The other two facilities, including the one under construction are hazardous waste incineration facilities. All of Utah's off-site hazardous waste management facilities are located in western Tooele County.

Data from 1991 indicates that 98% of the 3.5 million tons of hazardous wastes generated in Utah were managed on-site by neutralization and discharged to water treatment plants and wastes, were diverted from hazardous waste management by recycling or reclamation, or were disposed of in out of state TSDs (in order of magnitude). Only 2%, or about 4,073 tons of hazardous wastes generated in Utah were disposed of at Utah's TSD facilities. In 1991, 66,987 tons of hazardous waste were imported into Utah for treatment or disposal. Since 1991, this trend has reversed somewhat; currently wastes treated and disposed of in Utah are about 60% out of state and 40% Utah-generated.

Hazardous waste disposal in landfills is only acceptable for wastes that meet a set of criteria known as "Land Disposal Restrictions". These restrictions only allow wastes that have an extremely low potential to contaminate groundwater to be placed in landfills.

Hazardous waste landfills are rigorously engineered structures designed to practically eliminate the possibility of groundwater contamination. In addition, they are only located in Utah in areas that are remote from potable groundwater. These landfills are constructed with double or triple alternating layers of low permeability clay, liner fabrics, drainage and leachate collection systems. Any liquids collected in this system are treated and disposed of as hazardous waste. (Though no liquid wastes can be disposed of in the landfill, moisture may be introduced in the form of precipitation or residual moisture in the waste. Very little leachate is typically collected.) In addition to collecting any leachate that may accumulate, monitoring wells around the facility are sampled on a regular basis to detect any transmission to groundwater at the soonest possible time and the lowest possible levels (No groundwater contamination has been detected at any of the commercial hazardous waste landfills in Utah at the date of this writing). When the landfill cell is filled, it is covered with layers of soil, clay, geotextile fabrics and erosion control materials. Even after the cell is closed, the leachate collection system remains in operation, and groundwater monitoring continues for at least 30 years after the landfill is closed.

Contaminated soil, debris and incinerator ash make up the majority of the volume of material disposed of at hazardous waste landfills. Other wastes may be brought to the facility and further treated to allow them to be land disposed. These treatments may include solidification, stabilization or chemical precipitation. Hazardous waste landfills are permitted to accept only certain types or certain contaminant levels of hazardous waste. Many hazardous waste constituents, including most organic hydrocarbon wastes are "land-banned" from being disposed of directly in landfills, and must be treated by other methods first (such as incineration or stabilization) to reduce levels of the constituents of concern before being placed in a hazardous waste landfill. Therefore, the contamination or toxicity levels of the materials disposed of in landfills are typically very low because of this treatment requirement. Additionally, free liquids are not allowed to be placed in hazardous waste landfills. Liquid wastes must be solidified before disposal.

Hazardous waste incinerators have become accepted as a feasible waste management practice because they are one of the few methods that absolutely remove the waste from the environment by destroying it. The residual risk to human health attributable to these facilities is identified as residual levels of metals and halides (primarily chlorine) that may escape pollution control devices which process the incinerator's emissions, which could subsequently be inhaled by people or ingested by eating plants that these emissions had settled on. The facilities are designed to destroy or capture 99.99% to 99.9999% of these residuals. Because materials fed into the incinerator are rarely pure waste (soil, debris, sludges and liquids contaminated with hazardous waste at the parts per hundred to parts per billion range make up the largest volume of materials incinerated), emissions levels of hazardous contaminants are much lower than are permitted for industrial air emissions of the same constituents.

Hazardous waste incineration is a treatment method that uses the thermal energy value of certain hazardous waste as a fuel for combustion. The objective of incineration is to destroy hazardous wastes by completely combusting (burning) them. The result of incineration is a gas stream that carries with it fluid and particulate contaminants. The exhaust gases from complete incineration typically contain Carbon dioxide (CO₂) and water (H₂O), with lesser amounts of fine metal particles and Hydrochloric Acid (HCl) as contaminants. Hazardous waste incinerators have pollution abatement systems after the incinerator to remove these contaminants from the gases that are exhausted to the atmosphere. A baghouse is a common device used to filter out particles from the gas stream. An acid scrubber tower is a common device used to neutralize acids from the exhaust gases. An incinerator system can be designed with a vast combination of pollution abatement devices to accomplish a specific goal. The overall goal is to exhaust the least possible amount of contaminants to the atmosphere. An incinerator must demonstrate, prior to normal operation, that it is not emitting these contaminants above established standards.

In order to be permitted, incinerators must demonstrate in a Trial Burn period that they are capable of destroying 99.99% or more of the amount of waste incinerated. The incinerator must pass the trial burn under the most extreme conditions that the incinerator is designed to operate under: the highest concentrations of waste, the highest feed rates, and the lowest incineration temperatures. The incinerator is then required to operate well within these extremes to ensure that the destruction and removal efficiency that it demonstrated during the trial burn is being met or exceeded. Organic compounds composed chiefly of carbon and hydrogen, such as solvents, are frequently treated by this method. However, wastes that are incinerated frequently contain a broad mixture of organic wastes and wastes exhibiting the characteristic of toxicity. Pollution control sludges and incinerator ash, containing the remnants of the matrix the waste was in (soil is the major component) are disposed of in a hazardous waste landfill.

In addition to the facilities that accept hazardous waste from other businesses to treat or dispose of as a commercial enterprise, there are also several other facilities in Utah that treat hazardous wastes that originate at their facilities. The CAMDS and TOCDF facilities, both located at Tooele Army Depot are multi-unit hazardous waste incineration systems designed to separate and dispose of chemical munitions weapons (principally nerve agent and mustard agent, see Appendix for fact sheets and more information on these facilities).

CAMDS (Chemical Agent Munitions Destruction System) is a test incinerator that is used sporadically during development and testing of demilitarization processes, including the incineration of munitions. This facility consists of four incinerators: Liquid Incinerator (LIC); Metal Parts Furnace (MPF); Toxic Dunnage Incinerator (DUN); and Deactivation Furnace System (DFS). Each of the incinerators is designed to treat specific components of the stockpile munitions. The LIC is designed to incinerate liquid agent. The MPF is designed to treat, by incineration, large metal components, storage tanks, casings, and miscellaneous scraps that are potentially contaminated with agent. The DUN is designed to burn potentially contaminated trash generated from the demilitarization of the munitions. The DFS has several steps as part of the design. It is designed to break down some of the components of the munitions, by dismantling, shredding, and draining. Following the dismantling portion of the system, the explosive components and remaining body of the munitions are incinerated.

Testing that occurs at CAMDS can involve any combination of the demilitarization components of the process. Each test is designed with a specific goal and target information in mind. Information obtained from CAMDS testing is applied to the design and operation of other Chemical Stockpile Demilitarization Facilities. CAMDS has the capacity to burn about 600 pounds of waste per hour during operation. Since this is not a 'production' plant, it does not operate for the sole purpose of disposing of munitions. It only operates in conjunction with a testing campaign that includes preparation,operation and follow-up/conclusion testing.

The TOCDF (Tooele Chemical Demilitarization Facility) is also located on the Tooele Army Depot. It is the first of eight continental U.S. Chemical Stockpile Demilitarization (Stockpile) facilities to be built and operated for the destruction of the U.S. Army Chemical Stockpile of munitions. The facility consists of five incinerators: two Liquid incinerators (LICs), one Metal Parts Furnace (MPF), one Toxic Dunnage Incinerator (DUN), and one Deactivation Furnace System (DFS). TOCDF is permitted to burn a maximum of 6,250 pounds per hour of waste during plant operation. This is a combined maximum for all five furnaces and all waste feeds. The plant is scheduled to operate twenty-four hours per day, seven days per week until all of the stockpile munitions scheduled for disposal are managed. The total amount is not known, but is estimated to be approximately 42% of the nation's inventory of stockpiled chemical weapons.

Tooele Army depot stores the following types of agents in munitions configurations: Mustard Blister Agent (H, HD, HT), VX Nerve Agent, GB and GA Nerve Agents, and Lewisite Agent. The munitions contain propellants and explosives inherent to munitions. Incineration has been well defined as an effective treatment process for explosives, propellants, and chemical agents.

The largest hazardous waste management activity by volume that occurs in Utah is the treatment of hazardous wastes by the generator when the waste is only hazardous because of a characteristic, most frequently that of corrosivity. Acidic or alkaline waste waters, generated by many processes are most frequently managed by neutralizing and then discharging to a sanitary sewer. Other smaller volume hazardous wastes exhibiting other characteristics are sometimes dealt with on site by treatment as they accumulate. Wastes that cannot be treated in this manner must be stored and disposed of as hazardous wastes.

Waste minimization and waste reduction activities reduce or manage the potential risks of hazardous waste management by reducing the amounts or toxicity of wastes generated and by reducing the amount of waste that must be subsequently managed as hazardous waste. Many hazardous wastes that are generated are never disposed of because they are either re-used in other processes or are recycled to reclaim the usable portion or quality of the original material. Examples of this are re-distilling solvents to separate the usable solvent from particles of whatever the solvent was used to dissolve, or reclaiming silver from spent photographic developing solution. Use of waste materials in this way removes it from the waste stream, and removes it from consideration as a waste generation, storage or disposal risk.

Recycling and reuse are management techniques that minimize the amount of hazardous waste that is either treated by incineration or disposed of in hazardous waste landfills. As the costs of hazardous waste treatment and disposal increase and expand to include administrative costs and potential future environmental and legal liability, hazardous waste generators seek to recycle their spent materials and get as much use as possible out of them before disposing of them. The most common example of this practice is recycling of solvents. Spent, contaminated solvents are placed into a distillation apparatus that vaporizes and re-condenses the solvent, which is then clean enough to be used again. The economic advantage is two-fold: the amount of product that must be purchased is reduced, and the amount of waste that must be disposed of is reduced. The sludge, containing the contaminants, must be disposed of as a hazardous waste, but the volume of that waste is much reduced. This activity circumvents the production of a hazardous waste and is not reported as a management activity, therefore there is no good information source on how many tons of material are recycled this way. Other common examples of recycling are reclamation of silver from spent photographic solutions, and removal and reclamation of zinc sulfate and iron sulfate from acidic solutions used in steel galvanizing.

The information for this analysis of potential risks to human health was drawn from Hazardous Waste Activity Notification information, Biennial Report data, and from the expertise of the staff of the Utah Department of Environmental Quality, Division of Solid and Hazardous Waste. It is a qualitative analysis, because for the most part the information used was not gathered to address questions in a risk analysis context. In most cases, there is not sufficient information on the types of substances, amounts people or the environment are exposed to, or potential exposure pathways to "fill in the blanks" for a quantitative analysis. Rather than simply say- "there is not enough information and there is no way to say anything about these risks", this paper will attempt to broadly portray basic information. There are limitations to this approach: It is not as accurate or precise as a quantitative analysis, and any conclusions must be viewed with a high degree of uncertainty. However, if anything, this approach may help identify where knowledge is most lacking and further investigation is most needed.

Though there are between 1500 - 2000 materials that have the potential of being hazardous waste when disposed, chlorinated organic solvents or materials containing these substances are probably the most widely generated and managed hazardous waste. Materials containing high levels of toxic metals such as lead (Pb), chrome (Cr), cadmium (Cd), arsenic (As), and mercury (Hg) are another very predominantly generated hazardous waste.

The primary hazard of chlorinated solvents associated with generation and storage is inhalation of escaping fumes. The other potential hazard of generation and storage of these wastes is the hazard of potential release in an accidental or intentional spill. (The risks associated with this issue are addressed in the issue "Spills or releases of hazardous materials or wastes"). Prolonged inhalation of this class of compounds can cause liver, kidney and neurological damage (see Table IV).

The primary hazard associated with the generation and storage of toxic metal containing compounds is the threat of potential release to soil or groundwater. Because these materials are generally not volatile in the forms they are generated in, they are not as likely to escape to the environment via the air pathway.

The dose levels given for the following compounds have been shown to have acute and chronic health effects in animal models:

TABLE IV

1 LD₅₀= Dose level at which 50% of study population died

Information from "Draft Toxicological Profile for Tetrachloroethylene" and "Draft Toxicological Profile for Chromium", Published By U.S. Department of Health and Human Services, both October 1991.

Approximately 3.5 million tons of hazardous waste were reported to have been generated in Utah in 1991. There are currently approximately 1500-2000 businesses and other entities in Utah who have notified the state and EPA that they generate hazardous waste. An additional small quantity of hazardous waste is generated by an unknown number of additional facilities who generate very small quantities, who are not required to notify, and whose management requirements are less stringent.

Population exposed: Because of the association of generation and storage of hazardous wastes with industrial and service industries, urban populations have a greater potential of exposure than rural populations. However, these wastes are also generated (though at a lower density) in rural areas, so the potential for exposure exists there as well. Reduced possibility of exposure is directly related to the quality of waste management practiced by the generator.

Magnitude: For the most part (excluding spills or accidental releases) the concentrations of these constituents that would be found in the general environment (primarily air pathway) would be expected to be fairly small. Process controls and waste management practices are designed to minimize the amount of emissions of these wastes, and act to decrease the magnitude of exposure. Poorly managed facilities will increase the likelihood and magnitude of exposure for surrounding populations.

Duration: For people living near the point of generation of volatile wastes, duration could be expected to be consistent with the work schedule of the facility. The general population's exposure is intermittent and short-term.

Trend: Due to trends in waste management, including waste minimization and material substitution, the amount of hazardous waste generated by large facilities is tending to decline on a per facility basis. If Utah loses large manufacturing industries, waste generation totals in the state will decrease because each of these types of facilities tend to be large quantity generators. However, as the number of businesses in the service sector increases (corresponding with growth in urban areas in the state), the number of generators of small quantities of hazardous waste will increase.

3.2 POTENTIAL RISKS TO HUMAN HEALTH FROM THE TREATMENT AND DISPOSAL OF HAZARDOUS WASTES:

While there are over 1000 different hazardous wastes that are treated and disposed of in Utah, chlorinated organic solvents and metals-containing wastes comprise the majority of hazardous wastes that are treated and disposed of in Utah.

The primary health hazard from the treatment and disposal of hazardous waste comes from the possibility of exposure to the hazardous wastes or their treatment residues that may escape from the treatment or disposal process. There are two primary methods of treatment or disposal of hazardous wastes practiced in Utah: high temperature thermal treatment (incineration) and disposal in regulated, engineered hazardous waste landfills. Each of these methods poses different potential hazards via different potential pathways.

Incineration: The incineration process emits concentrations of chlorine and metals one to two orders of magnitude lower than concentrations permitted for many industries. The potential exposure pathways for these emissions are inhalation of particulate matter, or ingestion of foods on which these emissions have settled. Prolonged exposure to high concentrations of chlorine and heavy metals may cause non-cancer respiratory effects, liver and kidney effects (See Table IV).

Landfills: The primary hazard that hazardous waste landfills pose is the possibility of escape of hazardous waste constituents to groundwater beneath the landfill. Heavy metals such as lead, chrome, and cadmium are generally of greatest concern because of their predominance in disposed wastes and their potential health effects. There is evidence that prolonged exposure to heavy metals, using lead as an example, in drinking water may have caused kidney damage in a study of 283 people who had ingested drinking water contaminated with lead for a mean of 21.5 years. (Information from "Draft Toxicological Profile for Lead", October, 1991, U.S. Department of Health and Human Services) ,

Landfill: Metals leaching to groundwater (Lead as model):

(Information from "Draft Toxicological Profile for Lead", October, 1991, U.S. Department of Health and Human Services)

Incineration: Inhalation of trace metals in incinerator emissions (chromium as model, see Table IV):

Approximately 60,000 tons of hazardous waste were treated at Utah's commercial hazardous waste facilities in 1993 (a very large quantity of the hazardous waste generated in Utah consists of caustic wastewaters that are neutralized at the point of generation or are discharged to water treatment facilities rather than disposed of at hazardous waste treatment and disposal facilities). Of this amount, 16,000 tons were incinerated and the remainder was disposed of in one of two permitted landfills. All of these facilities are located in Tooele County.

Population exposed: The population living closest to hazardous waste incineration facilities is the most likely to be exposed to any measurable levels of air emissions. According to 1990 census data, there are from 0-5 permanent residents within a 4 mile radius of these facilities. Due to atmospheric mixing, it is expected that populations outside of this would not be exposed to measurable concentrations of incinerator emissions.

There were no drinking water wells noted in the area of the hazardous waste landfills in the state according a database maintained by the Utah Division of Water Resources.

Magnitude: The levels of emissions from hazardous waste incinerators in Utah are monitored during a maximum load-minimum efficiency trial burn period, and have demonstrated the ability to destroy or remove at least 99.99%, and in many cases, 99.9999% of the waste concentrations input to the incinerator under these less-than-optimum conditions. The levels of waste emitted by incinerators are difficult to measure directly; measurements of carbon monoxide and other constituents are used to indicate efficiency of combustion.

The permitted hazardous waste landfills have not been found to have released any detectible concentration of contaminants to groundwater.

Duration: Permitted hazardous waste treatment and disposal facilities have been operational in Utah since 1988. These facilities are expected to continue operations into the twenty first century.

Trend: The rate of addition of hazardous waste treatment, storage and disposal facilities to the state is expected to be very slow because of regulatory and political restrictions.

3.3. CHARACTERIZATION OF THE RISKS TO HUMAN HEALTH POSED BY THE GENERATION, TREATMENT AND DISPOSAL OF HAZARDOUS WASTES

The population potentially exposed to emissions from hazardous waste generation corresponds most highly with the population that lives adjacent to manufacturing and service industries. In this regard, most of the population of the state that lives in urban areas could be considered to be exposed. However, emissions at the source are rapidly attenuated by dilution in the atmosphere and the exposure potential would be expected to rapidly diminish with distance from the source. This would mean that most of those who are potentially exposed are exposed to very low levels of airborne hazardous waste constituents. Additionally, the constituents of concern that could be emitted from hazardous wastes are also emitted from other, sometimes more common sources, such as the case of benzene emissions from gasoline. (For a more complete discussion of these airborne sources, see the issue Air Pollution). Though it is not within the evaluative scope of this paper, the potential risks to people in the workplace who are engaged in the processes that generate these wastes are potentially exposed to significantly higher levels of these compounds, and are potentially exposed for longer or more continuous periods of time. Without proper safety equipment and training, these people may be at a significantly higher risk of cancer, or other non-cancer adverse effects. Cancer risks were not evaluated for this paper.

Management controls on the generation of hazardous waste are designed to minimize the potential risk from these activities. The most likely releases to the environment from properly managed hazardous waste generation activities are possible fugitive emissions from the generation and storage of volatile hazardous wastes. Waste reduction, by the use of less quantities of these hazardous waste-generating compounds, or substitution with products that do not produce hazardous wastes, can be significant means of reducing these risks.

The population potentially exposed to the risks of hazardous waste treatment and disposal is much smaller than the population potentially exposed to risk from hazardous waste generation and storage activities. This is primarily because all commercial, off-site hazardous waste treatment and disposal occurs in a single, sparsely populated area of the state. The risks associated with hazardous waste treatment and disposal center either on the potential for inhalation of hazardous waste treatment residues emitted by incinerators, or the potential of drinking water contaminated with hazardous waste constituents.

The potential risks of drinking water contaminated with hazardous waste constituents approach zero because of the absence of public or private drinking water wells within at least four miles of Utah's hazardous waste landfills. Additionally, intensive groundwater monitoring designed to detect releases to groundwater at the facility have not recorded an instance of contamination escaping landfill units to this date.

There is a fair amount of treatment of hazardous waste that occurs at the site where the waste is generated. However, this activity is strictly limited to certain materials (such as acidic or basic wastewaters) that do not pose a cancer risk, and must occur as the waste accumulates. In effect, this practice is a form of risk management in that the waste is rendered non-hazardous as it is generated, and does not have the opportunity to present subsequent risks during waste storage, treatment or disposal.

One of the risks of hazardous waste management, particularly generation and storage, is that of accidental release. This situation could pose significantly higher risks to human health than the risks due to fugitive emissions and emissions of residues. This risk is addressed in the issue Spills and Releases of Hazardous Materials and Wastes.

The controlled management of hazardous waste during the generation, storage and disposal process typically presents few risks to ecosystems or ecosystem components in Utah. The levels of fugitive emission from these facilities are usually relatively low, and concentrations decrease rapidly with distance from the source. Because most facilities that manage hazardous waste are located either in industrialized or urbanized areas, ecological resources have typically already been impacted significantly by the loss of habitat resources inherent in this type of development. This factor makes detection of damage due to hazardous waste management difficult. In general, hazardous waste management does not pose much of a broad-scale risk to Utah's ecosystems.

The stressors that could potentially impact ecosystems are the same ones that could potentially impact human health: airborne emissions of, or potential groundwater contamination by organic compounds, chlorine and metals

The concentration levels of hazardous waste constituents that may escape hazardous waste management, treatment or disposal could be expected to have similar impacts to individuals of populations in ecosystems proximal to hazardous waste management sites as to humans living in the same area.

Facilities with the greatest potential to impact groundwater during normal operations are located in an area of the state with no aquatic ecosystems hydraulically connected to groundwater that may be impacted by these sites. This, combined with the fact that ecosystems typically have limited access to potential exposure via groundwater, minimizes the hazard that hazardous waste management facilities may have on ecosystems.

For the most part, it is not known what environmental levels of these stressors would be required to impact ecosystems. Many of the dose levels which have been estimated for human health effects were determined in animal models, so presumably these levels would hold be relevant for populations of similar animal species that might be exposed to these constituents. However, an ecosystem is made of a diverse assemblage of many species of animals. Perturbations are buffered or stabilized by that diversity. Because of this, subtle effects on individuals in ecosystems are more likely to be compensated for and masked by the ecosystem, rather than magnified. Again, very little work has been done in this area, so this assessment must be viewed with some uncertainty.

Since ecosystems extend beyond the lifetime of the individuals inhabiting them, an additional factor of ecosystem dose response is reversibility. This can be defined as the ability of the ecosystem to regain its initial condition once the stressor is removed. In general, the longer the stressor is applied, the less likely the initial condition is to be restored, particularly if species begin to be excluded from the ecosystem by the stressor. In the case of the hazardous waste constituent levels in question, it is expected that ecosystems could reestablish their initial condition once the stressors are removed, if only for the reason that the potential effect at these levels is barely perceptible.

There are two general ecosystem types in Utah that have the highest potential of exposure to the effects of hazardous waste management. Hazardous waste generation and management typically occurs in the industrialized or urbanized areas of Utah that host ecosystems strongly impacted by that land use. In many respects, these ecosystems are already very far from their initial conditions. Urban/Industrial ecosystems typically contain less diversity of species, and the species that are present tend to be more tolerant of perturbations of the system. This is significant because the potential dose response of these ecosystems would be on the one hand harder to discern (see above) and on the other hand, less likely to effect many of the species in the ecosystem because of the increased tolerance of those species. Many of the state's industrial facilities are at present surrounded by fairly undeveloped areas that may support somewhat more functional ecosystems. These tend to be Rocky Mountain Ecoregion valley bottom (grassland) ecosystems that have been altered by historic previous activities. Several large quantity hazardous waste generators are also located adjacent to aquatic ecosystems.

The other ecosystem types that have the potential to be exposed to the effects of hazardous waste are those of the Great Basin Ecoregion, where the commercial hazardous waste management facilities of the state are located. This ecosystem is composed of a variety of arid adapted habitats that tend to be determined by elevation or by soils. Valley bottoms with saline soils contain communities of salt adapted plants and sparsely distributed small animal and insect populations that live off of these plants. Higher elevations grade through salt scrub to sagebrush steppes to stands of pinyon and juniper on the mountainsides of the Greyback, Cedar, Lakeside and Stansbury mountain ranges. The few areas of sufficiently high elevation grade into sub-alpine communities. Species density and diversity gradually increases with increasing elevation, but is in all cases relatively low.

In both main ecosystem types potentially exposed to hazardous waste management, the degree of exposure to individuals would be expected to be comparable to the degree of exposure human populations would experience. However, exposure to ecosystem populations could have to be adjusted to a slightly higher level because of the fact that ecosystem populations would be expected to be continuously exposed to the constituent, and have the potential to be additionally exposed through the pathway of ingestion of materials that have accumulated the constituent. No studies have been completed to date in Utah to determine these exposure levels. However, there are several studies in progress associated with Department of Defense facilities and hazardous waste management facilities that will assess this exposure potential. In the case of Urban/Industrial impacted ecosystems, the degree of exposure to hazardous waste constituents would be difficult to separate from exposure to other environmental stressors such as surface water pollution or habitat restrictions.

As Utah's population and economy expands, it can be expected that the amount of hazardous waste generated and managed in the state will increase. This factor may increase the amount of potential risk that Utah's ecosystems may be exposed to. However, this risk will continue to be outweighed by the risks inherent in the urbanization process.

The risks to Utah's ecosystems associated with hazardous waste treatment and disposal can also be expected to increase. It is not projected at this date that any more off-site hazardous waste facilities will be built, so any increase in risk would be due to increases of treatment and disposal volume. This increase is being offset at present by waste minimization efforts at many generating facilities, resulting in a decrease in hazardous waste treatment levels over originally projected levels.

Based on the factors presented in the assessment above, Utah's ecosystems are at minimal risk from the generation and management of hazardous wastes, particularly when compared to the greater ecosystem risks posed by the urbanization that hazardous waste management is typically associated with. The management practices that are designed to minimize the risk to human populations can also be expected to be protective of individuals of ecosystem populations. The levels of hazardous waste constituents that ecosystem populations could be exposed to would be expected to be comparable to levels humans may be exposed to. However, duration and intensity of exposure may be higher because of the greater percentage of time they those populations may be exposed, and because they may be exposed to the additional pathway of ingestion of materials that have accumulated hazardous waste residues. The potential of exposure via groundwater, primarily an issue with drinking water wells in the vicinity of hazardous waste landfills, would be expected to be practically non-existent.

One of the risks of hazardous waste management, particularly generation and storage, is that of accidental release. This situation could pose significantly higher risks to ecosystems than the risks due to fugitive emissions and emissions of residues. This risk is addressed in the issue Spills and Releases of Hazardous Materials and Wastes.

The environmental risks associated with hazardous waste generation and management at the point of generation (storage, on-site treatment) has traditionally not been the focus of a great deal of discussion or debate regarding those aspects that constitute "quality of life". Many of the regulations that deal with protection of those working with hazardous materials and the proper management of hazardous waste are intended to protect people from factors that may tend to decrease quality of life such as adverse health effects, nuisance, or destruction of the environment.

Whether hazardous wastes should be generated or not has traditionally not been much of a quality of life issue, either. The assumption was that these wastes were a necessary by-product of the production of goods or services that increase quality of life. Hazardous wastes are generated in the production of almost every synthetic material in use today and a good number of "natural" materials; they are also produced during the performance of many services such as auto body repair and dry-cleaning. But many of the consequences of hazardous waste generation are now being seen to potentially impact quality of life: the cost and necessity of hazardous waste disposal, the potential for risks to human health and the environment, and the economic cost of dealing with those risks. This realization is causing an increasing number of generators and consumers to rethink the assumptions about hazardous waste generation. They are trying to find ways to generate less wastes, and buying products that generate less wastes during use or are not themselves a hazardous waste when disposed of.

Another quality of life issue revolving around the generation of hazardous waste that was commonly brought up during public scoping meetings held by the Comparative Risk Assessment technical staff was the cost and complexity involved in complying with hazardous waste management regulations. While this issue is technically not related to the risk of hazardous waste generation or management, and is considered to be outside the scope of the Comparative Risk assessment process, it is a significant concern.

Hazardous waste management after generation-- the treatment and disposal of hazardous waste-- has been and will continue to be the focus of a great deal of public concern about quality of life matters. "Fairness" issues such as where facilities are located, if the public should be subjected to perceived risks involuntarily, if Utah should accept wastes from other states, and if Utah is becoming a "dumping ground" for hazardous wastes have provoked extensive and ongoing debate. Positions range from the contention that hazardous waste management is a viable industry that can safely contribute to the state's economy to the view that the presence of hazardous waste management facilities enables the continued unnecessary and harmful generation of hazardous wastes. These arguments are as grounded in personal values, beliefs and world view as they are in technical considerations, and there are no easy or "right" answers.

Hazardous waste generation is generally tied to the production of goods and services in widespread use in modern civilization. Rates of production and quantities produced range widely from industries which produce raw materials, such as steel or fuels; to service industries such as dry-cleaning and auto body repair. These businesses form a large percentage of the total industries in the state. While the primary costs of hazardous waste generation may not be high, the secondary costs of generation: disposal, employee training and protection, insurance, regulatory compliance, etc. may cumulatively be quite costly. These costs may be incorporated into the costs of goods and services. Because of these costs, many generators are exploring possibilities of product replacement and hazardous waste reduction. This has created an industry involved with the management of hazardous waste from the generation standpoint, including waste minimization consultants, waste management auditors, and site clean-up consultants and contractors. There were over 80 of these companies listed for the Salt Lake area in 1993. So, while the number of companies involved with the generation of hazardous waste in Utah (both directly and in the consulting field) may be expected to increase in the future, the rate of generation may decrease as non-hazardous waste generating alternatives become available.

Hazardous waste treatment and disposal facilities in Utah may play a fairly large role in certain sectors of the state's economy despite the small number of facilities in the state. At this time, there has been no economically based cost/benefit analysis performed regarding the presence of these facilities in Utah. The information below is presented more for consideration than as a definitive assessment of the positive and negative impacts of the hazardous waste industry on the state.

There is relatively little quantitative information available concerning the amount of property taxes, sales taxes and corporate taxes these companies pay, but it can be assumed that these monies are a fairly substantial contribution to the economy of the county they are located in (Tooele county). It is estimated that the hazardous waste treatment and disposal industry has an annual payroll of approximately $16 million; most of these jobs are relatively high-paying. The presence of this industry could confer additional inputs to the state economy in the way of support service companies, and lowered costs of waste disposal for hazardous waste generators in Utah due to the proximity of these facilities. A hazardous waste disposal fee paid per ton to the state funds governmental oversight of these facilities, in addition to providing support for other state hazardous waste programs.

The costs to the state from this industry are difficult to evaluate, but could conceivably include potential health costs to employees and the citizens of the state (see health risk evaluation), loss of desire of individuals or new industries to locate to Utah because of the presence of these facilities, or loss of income from recreational or tourist visitation in the state because of these facilities.

Hazardous waste generation and temporary storage occurs on site at industrial facilities and at businesses. No additional land is required to manage hazardous waste, nor must land be diverted from other uses to manage wastes.

Utah's hazardous waste treatment and disposal facilities occupy fairly small parcels of land in Tooele County with a total of less than 3 square miles utilized by these facilities. Surrounding lands may be privately owned, or federally owned and managed by the U.S. Bureau of Land Management with scattered state land inholdings. The land surrounding the facilities is presently designated as range land, primarily used for grazing; this use has not been compromised by the presence of the facilities.

There are two trends regarding hazardous waste generation and growth that tend to balance each other out. If Utah's economy grows, particularly in the direction of high technology manufacturing jobs, it can be expected that there will be some increase in the number of companies that generate hazardous waste. As Utah's population grows, there will be an increase in the number of goods and services providers in the state that generate hazardous waste. Balancing this upward growth is a trend towards decreasing amounts of hazardous waste generated by each facility. This expected decrease is due to a variety of factors including an emphasis on pollution prevention and reduction, the costs of managing and disposing of hazardous wastes, and the availability of substitute products that do not generate hazardous wastes. The amount of hazardous waste generated in the state will probably grow over time, but the rate of growth will probably decrease due to waste minimization efforts; the net rate of growth is difficult to predict.

Hazardous waste treatment and disposal in Utah is not expected to grow much in terms of numbers of new facilities in the near future because of regulatory requirements (including legislative and gubernatorial approval of new facilities) and public pressure. Competitive pressures in the hazardous waste treatment and disposal industry appear to be fierce at this time; market growth of the facilities in Utah measured in terms of amount of waste accepted has actually declined over the last two years.

Because the services directly associated with tourism and recreation (hotels, restaurants, entertainment) do not generate large amounts of hazardous waste, an increase in these activities would not be expected to impact hazardous waste generation significantly. However, an increase in secondary activity associated with tourism and recreation, such as manufacture of products to sell to visitors, repair of rental cars, etc, may occur. It would be difficult to separate this out from general economic growth though.

Hazardous waste treatment and disposal does not appear to have much impact on tourism and recreation. Public concern or opposition over the presence of these facilities does not appear to detract significantly from Utah's desirability as a tourism destination. The facilities themselves are not located near any major tourism and recreation destinations. Where they are located en route, they tend to be unobtrusive. Travellers between Salt Lake City and Wendover, a major regional tourist destination, pass within 2 miles of one hazardous waste management facility, probably without realizing it.

The primary concern over hazardous waste generation and subsequent management-- storage, treatment and disposal-- is primarily concern about the risk of serious potential harm to human health and the environment if wastes are mismanaged or improperly disposed of. The potential risks that remain even after the best management and risk reduction strategies are employed is termed residual risk, and is the subject of this assessment.

The direct residual risks to human health from hazardous waste generation are primarily expected to come via the air pathway, through inhalation of vapors or fumes emitted by the wastes during generation or storage. They are generally low for the general public because direct contact with hazardous wastes is minimal, and atmospheric concentrations decrease rapidly with increasing distance from the source. Also, because most hazardous waste generation takes place in an industrial or urbanized area, the risks from hazardous waste generation may not be discernible from the risks due to other environmental factors such as air emissions from industry or automobiles of the same constituents in the area. The residual risks of concern resulting from hazardous waste treatment and disposal are the potential for contamination of drinking water resulting from land disposal of hazardous wastes, and the potential for exposure to airborne emissions (primarily halogens such as chlorine, and heavy metals residues) from hazardous waste incinerators. The two primary factors mitigating this risk are the extremely low concentrations of these materials in incinerator emissions, and the distance these facilities are located from population centers. Quantitative risk assessments are underway for these types of facilities in Utah; there is limited data at present.

Hazardous waste generation and management are expected to present minimal risk to Utah's ecosystems or ecological resources. Most hazardous waste generation points are located in environments that are already heavily impacted by the urbanization process, and additional impacts to the ecosystems that are in these areas would be extremely difficult to detect. Impacts to less disturbed ecosystems surrounding hazardous waste disposal facilities may be easier to model, and there may be slightly more risk to individuals of ecosystem populations than to individual humans, but ecosystem impacts would be more difficult to discern. There has been little scientific work done in this area; again, risk assessments are underway which should eventually provide more information.

Several "quality of life" factors are discussed in this assessment, relating to public awareness and opinion, economy, land use, growth and recreation. These areas are not objective assessments, rather they are points that the reader may use to evaluate his or her own feelings as to how hazardous waste management impacts life in Utah.