105635 An Analysis of the Impact of the Regulation of "Radionuclides" as 3 Hazardous Air Pollutant on the Petroleum Industry Prepared for the Committee for Environmental Biology and Community Health, Department of Medicine and Biology, American Petroleum Institute October 19. 1982 EMLEI 0069428 The impact of regulating "Radionuclides" as a hazardous air pollutant under Section 112 of the Clean Air Act is examined and is found to depend upon what is defined as an "acceptable level" of risk, and whether the regu- lation will be based upon committed dose equivalent to the general public, source characteristics, or individual radioisotopes. Almost all materials of interest and use to the petroleum industry contain measurable quantities of radionuclides that reside finally in pro? cess equipment, product streams, or waste. In addition, groundwater used for waterflood and brine solutions from operating wells contain biologically significant quantities of Radium 226 and Radon 222. The mining, cleaning, and combustion of coal also add measurably to the burden of radioactive pollutants in ambient air. Listing radionuclides as a hazardous air pollutant also brought radionuclides under the umbrella of CERCLA. Again, the impact of defining a "reportable quantity" depends upon the definition of "acceptable risk" and whether the standard is based upon a committed dose equivalent to a member of the general public or is established isotope by isotope. Table 10 in the main body of the report summarizes the quantities of radionuclides found in products and raw materials of most concern to API member companies. Table 13 summarizes the EPA's estimate of risk associated with certain industry operations to a maximum exposed indi- vidual inhaling and ingesting radionuclides from products of combustions. Table 17 shows how the impact upon the industry expands as the level of acceptable risk is reduced,'and Table 18 summarizes the combined potential impact of regulations under both the Clean Air Act and CERCLA. It is concluded that the regulation of radionuclides could impose a severe burden on API member companies, and it would be prudent to monitor closely both regulatory actions. EMLEI 0069429 What Radionuclides Should Be of Concern? When the EPA listed as a hazardous air pollutant, they meant all radioactive materials without exemption for material concentration activity). quantity, or material with which it is associated. There were no exemptions for the non-nuclear industries. The general classification "Radionuclides" includes: 0 By-Product Material - the material made radioactive through the use of special nuclear material or bombardment by radi- ations resulting from the use of special nuclear material (CFR, 1982). 0 Special Nuclear Material the fuel for reactors. Source Material - essentially the concentrated elements from which special nuclear material is separated. 0 Naturally Occurring or Accelerator~Produced Radioactive Materials those radioactive materials found in nature or made radioactive in a laboratory by an energetic ion beam. These are the materials that are present in our products in minute amounts. While many petroleum companies use radioactive materials as tracers and in process control, these are carefully regulated by the U.S. Nuclear Regulatory Commission present little, if any, environmental hazard, and are of small concern. The API should be more concerned with the potential for naturally occurring radio? nuclides being in our raw materials. Naturally occurring radioactive material is either produced in the earth's atmosphere as a result of cosmic?ray bombardment, i.e. Carbon?14, or exists as primordial radionuclides, i.e. radionuclides present from the event of creation in the earth's crust, such as Potassium 40 and Uranium. The families of radionuclides or series of radionuclides that are of most signifi- cance are in this primordial grouping. These are the decay series of Uranium 238, Uranium 235, Thorium 232. Uranium 235 is the nuclear fuel. About 0.71 of natural uranium is Uranium 235. Uranium 238 and Thorium 232 are uniformly distributed in the earth's crust. The Uranium 238 (Figure 1) series can be divided into some four subseries, all possessing significant expusure potential to man. These subSeries are the decay of Uranium 238 and Uranium 23k to Thorium 230. the decay of Thorium 230 to Radium 226, the decay of the inert gas Radon 222 and its short-lived daughters to the long-lived daughter, product Lead 210, and finally the decay of Lead 210' to stable lead (NCRP, 19753. The elements in the Subseries Uranium 238 to Thorium 230 represent significant sources of internal exposure, primarily in the occupa- tiOnal environment. Radium 226 is a potent source of radiation exposure, both internal and external. Radon 222 and its short-lived progeny deliver significant papulation and occupational exposures to the upper tracheobronchial tree, while Lead 210 and its decay product contaminate much process equipment and can repre- sent significant exposure to the bone in some occupational subgroups. Radon 222 and its daughters cause the most severe impact to the public health. EMLEI 0069430 The Thorium series (see Figure 2) is characterized by the long?lived Thorium 232 at the head of the series and decay products that are relatively short lived. If no migration of the series members takes place, radio- equilibrium is established in about 60 years. In minerals and rocks of low permeability, the thorium series radionuclides are expected to be in equilibrium. In soils, natural waters, natural gas, crude oil and the atmosphere, the disparate chemical and physical properties of the series tend to cause disequilibrium. Certain parts of the world, Kerala in India and monazite mining districts in Brazil, are famous because of their high background levels of external radiation from the thorium series. The Presence of Radionuclides in Crude Oil, Natural Gas (HG), Liquefied Petroleum Gas (LPG), .Coal, Phosphate Rock, and Groundwater It is Well known that some naturally occurring elements, uranium for example, have an affinity for crude oil. The uranium that accumulates in crude oil, oil shale, coal, and phosphate rock is the residue remaining after.. the marine deposits have been consolidated. Petroleum is often assumed to have migrated to a position of minimum hydraulic potential in a "reservoir rock", which may or may not be derived from the same source deposits as the petroleum. Associated with the petroleum in widely ranging proportions are brine and natural gas. The radionuclides, particularly those of the uranium series (see Figure distribute themselves among the three fluid phases and the crusty, solid lining of the intergranular spaces according to chemical affinity, sorption phenomena and the vagaries of radioactive recoil. The gaseous radon isotopes follow the temperature?pressure dependent Henry's Law in their portioning among the gas and liquid phases. The sites of major uranium-series nuclides in the Texas Panhandle gas field and adjacent areas have been studied extensively (Pierce, 196a). In the gas reservoir, uranium is resident mainly in the crude oil and in pellets of solid hydrocarbon, radium is found in the brine and in the solid crust, and radon distributes itself among the oil, gas and brine in that order. The series equilibrium is evidently disrupted continually by movement of decay products from one phase to another that is chemically or physically more compatible. . Crude Oil Very little has appeared in the literature concerning the levels of radioactivity in-crude oil, but it would be safe to assume that the actual levels of contamination?would be between that feund in coal and that found in sedimentary rock similar to that of the reServoir rock or where the petroleum was formed. Uranium in the earth's crust averages 4 parts per million (CRC, 1969). The NCRP (NCRP, 1975) reported the data shown in Table for the various rock types. EMLEI 0069431 TABLE. 1 -Summary of o] mqjor radionuclidu in majm rock types and soil- Peluu?un?w RubldIun-? ?mien-DZ Uranium-m It?d Type Wren?. "rm lot-l 9cm; (on! pm.? ppm. pCUc' Polusimn lubldum [amou- Rock- Bmalt (CI-um! 0.3 1 40 14 0.34.! 0.34 0.1-6.3 Iver-n) 0.34.! 10-50 Ll, 1.1 0.3. 0.3 0.3. 0.1. 0.1 Solic? 4?5 Iva-m 1.3, Grumman-u! >4 >10 Ito?m (-8 LI - a I Iva-(I) Sodium-buy ?nch Sluts 22 130? l: 1.8 3.1 Sand-tonal: den qua-u 232 l.9?00 6.2E-l l.lE-1 i.9?to 6.26-I 1.1E-3 Table 12 (Cent.) SUMMARY OF RISKS FROM SOURCES OF AIRBORHC EMISSIONS 0F RADIONUCLIDES Dose Equivalent Holes lung Bone Lung Liver Dane Bone Bone Bone Bone Lung none Lung Balm fipOde lluivlduol (?ran/yr) i.2 l.JEtl l.2tl 3.]E0l Collective person- 5.7E02 3.6Et] 2.8Etl 1.7Etl 2.9EDZ 2.2Evl 7.4Et2 6.2E92 l.5Etl 5.2EOI legal) Radon Daughter [xpusure Regional Population (perion Haxinmm Individual (working Negligible Negligible vorlln Lifetime Health Eifeclt Fatal Cancerx per Year of Operllion to the Population 1! ?iik JE-Z 19. EMLEI 0069446 Operation Ground Water Treatment Southeastern Site Southwestern Site Geothermal Power Coke Production Northeast Southeastern Coal Fired Steam New Midwestern Southeastern Existing Coal Fire Industrial'Boilers Eastern Midwestern Coat Mining and Cleaning Underground Mining Mining Coal Cleaning Natural Gas Combustion Natural Gas Turbine 13 Summary of Operations Whose Regulation Will Impact On Member Companies . isotype oi interest 2228" 2128" 232Th :topu ZJIU ditto 23.? assu ditto ditto ditto ulU ditto ditto nan" Llietime Risk to the Maximum Exposed individual 6 x1o-' 1x1v? 1x10-? ex1m? 1 x10? 5 x1o-? 5x10? 3 10-5 3 x10-5 9 x10? 5 x10? 1 10? 3 x10-I 4 x10.? 21. 22. Regulatory Option?_and Their Implications As far as industry is concerned. the regulatory issues should be: 1. What is an "acceptable level of risk"? 2. Which approach will be Followed in setting the standard. a generic "committed" dose equivalent approach or regulation isotope by isotope? The EPA risk assessment in part evaluated the risk to a "maximum exposed individual?. The risk to this person from sources of interest to the API ranged from 9 10'3 (underground coal mining) to 1 10'6 (coal cleaning) Risks for this individual resulting from the combustion of fossil fuels ranged in the 5 10-5 area (Ieknekron, 1981). Table 1a (Wilson, 1981) gives an indication of how those risks compare with others "accepted" by United States residents. The federal bureaucracy also has been pondering ever the concept of _5 acceptable and de minimis risk. Dr. Roy Albert has been supporting 1 10 excess lifetime risk of fatal cancer in the drinking water area. The FDA has accepted 1 10?6 excess risk as acceptable for acrylonitrile migratioz in food containers. The USNRC is considering in staff discussions 1 10? excess lifetime risk of and 10"6 excess lifetime risk of death or lower as de minimis. The EPA assessment lists the? combustion of fossil fuels as and 10-5. In addition to the definition of accEptable risk, the method of setting the limits could have considerable impact. There are two methods available to the EPA: regulate population?committed dose equivalent to air pollutants, the generic approach; or limit the emission of specific radionuclides. by an individual does not produce a risk of fatal cancer exceeding that of preselected whole?body dose commitment (ICRP, 1977; ICRP, 1980). Mathematically, this can be expressed as a I ?5 i where'dd is the deep dose commitment or (whole body dose) Ii j" is the annual intake of radionuclide by inhalation Io is the annual intake of radionuclide by the oral route is the annual intake by inhalation which will i provide a risk equal to a deep dose is the annual intake by the oral route that will produce a risk equal to a deep dose commitment D, and is the deep dose commitment resulting in an aCCEptable level of risk 5 EMLEI 0069447 23. TABLE 14 DEFINED LEVELS OF RISK ANNUAL RISK OF DEATH OF DEATH p.1- Motor Vehicle Home Accidents ii '3 7 Occupational Radiation Exposure Occupational (5 Rem per year, 50 years) Fails ll? 1 1111] II Significant Natural Radiation Background ii EPA-- Drinking? Fire Arms 1: 10-5 Water Pesticides Poisoning 1: (All Forms) Eiectrocution i Acceptable i Technologicaily Enhanced Radiation (API Sources) Acryionitrile Floods De minimis'Risk Proposed ?g USNRC (0.1_Milli Rem, per year) Tropical Storms -- a 10-7 *Being considered in revision of 10cm 20 Standards ior Radiation Protection. This is not an agency position. EMLEI 0069448 24. -4 ?The risk factor for whole body radiation is about 1.65 10 fatal cancers per Rem (ICRP, 1977). If we calculate the committed whole body dose equivalent to produce an excess lifetime risk of 10?5, we find ?5 cancer death rem -4 cancer deaths 10 lifetime yr) 1'6 x-lo rem and that D, the whole body committed dose equivalent whole body, is 62.5 milli- rem for a single exposure. If we further average that exposure over a lifetime. as would be realistic for an air pollutant. the dose committed is 0.9 millirem/ year. It could then be concluded that exposure to radioactive materials in combustion products of interest to the API plus all other sources should be less than 0.9 millirem per year. The second approach, one based on a variant of derived air concentrations (DAC), is less complicated and perhaps more reasonable. It encompasses a bubble concept in that only that material leaving the plant confines is of interest. If the concentration of radionuclides, Uranium, Thorium, Radon, etc., is less than an established limit based on the Annual Limit of Intake (ICRP, 1980), the plant would be in compliance. It must be recognized that the current occupational DACs would have to be adjusted for 24?hour exposures and for the most susceptible exposed population. Cumpliance could be judged on an isotope~by-isotope limit or added in the manner of the TLV as below: Conc Conc Th 1 DAC Th where Conc is the concentration of the element of interest and DAC is the derived air concentrations for that environmental exposure. The advantage of this system would be that each location could measure its own compliance without regard for air modeling, transport and dose reaponse modeling.? The disadvantage would be that the measurement is both difficult and expensive to make. Table 15 compares the two methods and gives estimates of some limits. For either approach, 10?5 excess risk permits very small increases over the natural background. Similar approaches as.those suggested to regulate air pollutants are being applied to the development of the Reportable Quantity under CERCLA. Table 16 estimates the amount of raw material or product that will contain one reportable quantity of selected radionuclide for a weight, activity, or dose?equivalent approach. Depending on the mode of definition, very small quantities of petro- leum products could easily contain reportable quantities of radionuclides. EMLEI 0069449 Table 15 Estimate of Radioactive Material Concentrations to Produce 10 Lifetime Excess Risk of Fatal Cancer to a Maximum?Exposed Individual Concentrations to Produce 10..5 Excess Risk in Target Population . (curies per cubic meter) 25. Solubility At Stack Ac Fenceline Radioisotoge Class Generic* Uranium 238 1 8 10-1? 6 10-15(8) 2.6 10?8 a 10'1? 1 10-1? (1) 2.5 10'1? Thorium 232 ?11 6.5 10?17 2 10'15(s) 6?5 10 1.3 10'16 2 Radium 225 3.9 10?8 3.9 10?14 (S) 6 10-15 (1) a 10'15 Radon 222 5.2 10?6 5.2 10'12 6 10?12 Lead 210 1.3 10"8 1.3 10'1? 8 10?15 1.6 10?1? ?6 Assumes 10 dilution factor, and the children (10-year old) as the target population, 15 m3 air inhaled per day (ICRP, 1975). Assumes children (lovyear) as target population. EMLEI 0069450 EMLEI 0069451 item/Product Crude Oil Natural Gas LPG US Coal SRC Product Shale Oil Shale Waste Phosphate Rock Ground Water TABLE 16 Amount of Product Needed to Assemble One Reportable Quantity of Uranium or Radon One Pound 2,162 4.9 1016 MCF 33.6 252 890 151 3.98 4.4 1016 Gals. Possible Form of Reportable Quantity One Milli. Curie 14,200 714 MCF 714 MCF 222 1,600 5,882 1,000 26.3 6.04 10? Gals. One Micro Curie 14.2 714,000 CF 714,000 CF 0.2 1.6T 5.8 1 .026 6.04 105 Gals. 5Rem' Committed Dose Equivalent 0.5 .017 MCF .071 MCF .88 .067 0.24 .04 .001 2.5 104 Gals. 26. 27. Control Options Any control methodology proposed for radioactive materials must recognize the fact that radioactivity can not be modified or made inert by chemical means. It also must recognize that radioactivity dissipates at fixed rates through fixed sequences or series. Decay to daughter products cannot be guaranteed to reduce the hazard. The control of emissions of naturally occurring radioactive materials can be accomplished by removing the radioactivity from the raw material or product. or by removing the radioactive materials after combustion. This removal can be accomplished by-taking advantage of radioactive decay; by physically removing the radioactive material by washing, filtering, or by absorption; by chemically scrubbing the material from the product or combustion gas stream; or by combination thereof. The removal of Radon 222 from natural gas could be accomplished by either decay or by absorption on a molecular sieve such as activated charcoal. Radon has a 3.83 day half-life. Storing natural gas for 5 half?lives approximately, 20 days would change some 99.52 of the Radon in the influent stream to 21?year Lead 210, much of which will plate out in the storage tanks, pipeline, and process equipment. When one compares the derived air concentration for each, however, it appears that the relative health hazard may have been increased. The DAC for Radon plus daughters, target organ the lung, is 3 10'8 C1 per cubic meter, while that for Lead 210, target organ bone, is 1.x 10"10 (ICRP, 1980). Capturing the Radon on a molecular sieve and the Radon daughters on a highrefficiency (HEPA) filter cleans the product stream but changes a very dilute source of radioactive materials into a very concentrated source of radioactivity, presenting both an internal and external radiation hazard. The removal of Radon from groundwaters can be accomplished by aeration (which releases the radioactive material to the ambient air) or through decay. The decay again introduces Lead 210 into the water which, again, is not totally free of'hazard. The Lead 210 can be removed using bacterial filters; diatomaceous earth, with the resultant hazards associated'with concentrating radioactive materials. Uranium in crude oil presents a somewhat different dilemma. We estimated earlier in this paper that significant quantities of uranium potentially enter our refineries via crude 011. Little is known of its fate, however. Since the law of conversation of matter must apply, it can only end up in the product, the process waste, remain in the process equipment. or escape into the environment. The chemical properties of uranium suggest something concerning its ultimate fate. Uranium can be isolated by reducing uranium halides with alkali or alkaline earth metals or by reducing uranium oxides by calcium, aluminum or carbon at high temper- atures. Strong acids can dissolve the metal, but~it is relatively unaffected by alkali (CRC, 1981). It would seem likely to find most of the uranium plated out in the process equipment or concentrated in process wastes. Better understanding of the presence and fate of uranium in fuel oils is needed before a control scheme can be proposed. EMLEI 0069452 28. The main contaminants in coal are members of the Uranium 238 decay series, primarily Radium. Radon, and Uranium. Cleaning the coal will remove much of the radioactive materials on the surface of the coal but will concentrate the material in the waste water. Pulverizing the coal will release much trapped radon to the atmosphere. Combustion will cause most of the radioactivity to be concentrated in the fly ash. High-efficiency scrubbers or filters may be' required to reduce the health risks of such exposures to acceptable levels. Impact of Regulation on API Members The impact that the regulation of "radionuclides" under the Clean Air Act (6AA) will depend largely upon what the EPA decides is an "acceptable risk". answer in 180 days. The EPA has been forced to make this decision, and we will know the What the EPA decides depends largely upon what society; as represented by its most vocal members, wants. Table 14 gives some indication of what we might expect, and it is likely that lifetime excess risks greater than one one-hundredth of that imposed by the natural background (1.5 10?5) will be It is also equally likely that excess risks less Table 17 summarizes candidates for considered unacceptable. than 10"7 will be considered de minimis. regulation for different levels of acceptable risk. Table 17 Operations Subject to Regulation as a Function of Defined Acceptable Risk Acceptable Risk Level (Lifetime Excess Risk of Contracting Fatal Cancer) 1.5 10'5 Geothermal Power Coke Production (all locations) Coal-Fired Steam Coal-Fired Industrial Boilers Underground Coal Mining 5 10?6 Groundwater Use (all locations) Geothermal Power Coke Production (Northeast only) Coal-Fired Steam Coal-Fired Industrial Boilers Underground Coal Mining Strip Mining (coal) 1 10?6 Groundwater Use (all locations) Geothermal Power Coke Production (all locations) Coal-Fired Steam Coal?Fired Industrial Boilers Underground Coal Mining Strip Mining (coal) Coal Cleaning Natural Gas Combustion Natural Gas Turbines EMLEI 0069453 29. The impact of CERCLA on API members depends on the definition of reportable quantity. The data collected in this report appear to suggest that the CERCLA will place reporting requirements on many operating locations. The impact of both regulatory actions is summarized on Table 18. It appears that regulation of radionuclides could impose a severe burden on API member companies and that both regulatory actions should be closely followed. EMLEI 0069454 EMLEI 0069455 Operation Production Gas Liquids Crude Oil Water Flood Brine Disposal Disposal oi Scrap Equip., Pipe etc. Manufacturing Process Heat Power Generation Gas Turbine Gas Furnace Coal Geothermal Disposal oi Process Equip. Bottoms/Sludge Coal Mining Underground Strip Mining Cleaning Radio- IsotOpes '"Rn+d zaz?n+d 23lU+d mRn+d ??Ra+d zsrU+d ?la a mRn+d 210Pb man+d mRn+d mam "?Rmd nIU+d HID "?Ra+d ditto ditto TABLE 1.8 Potential Impact of Regulation on API Form Gas Liquid Liquid Gas Solid 'Soud Solid Gas Solid Gas Gas Gas Solid Solid and Gas Gas Solid Liquid Solid Solid 8: Gas ditto ditto CAA Potential For M. CERCLA XX XX XX Potential Impact Removal of Radon (20 day storage) Removal of Radon (20 day storage) Reporting and Control Control Release of Radon- Control Reieaseoi Radon Reporting and Control, Disposal Site Reporting and Control at Disposal Site Control of Release of Radon. Control at Release at Radon Control at Release at Radon Control of Release at Radon Control at Release of Radioactive materials. Control at Release of Radon Radon lrom Fiyash Disposal Site. Control at Release at Radon Reporting and Control at Disposal Control at Release of Radon Reporting and Control oi Disposal Control at Release of Radon Control at Release of Radioactive Materials and Radon ditto Reporting and Control ol Waste Disposal Site 30. 31. References (Baas, 1981). Haas. C. F. and Sharp, R. A Directory of Parameters Used in a Series of Assessment Applications of the Air and DARTAB Computer Codes, Oak Ridge National Laboratory, ORNL S710, 1981. (Barber, 1977), Harbor, D. E., and Giorgio, H. R.: Gamma Ray Activity in Bitu- minous, Subbituminous, and Lignite Coals; Health thsics, Volume 32, February 1977, pp. 83-88. (Begovich, 1981), Begovich, C. L., et al; DARTAB: A Program to Combine Airborne Radionuclide Data with Dosimetric and Health Effects Data to Generate Tabulations of Predicted Health Impacts, Oak Ridge National Laboratory, ORNL 5692, 1981. (CFR, 1982) Code of Federal Regulations, Title 10, Part 20, Standards for Radiation Protection, Paragraph 20.3, April 23; 1982. (CRC, 1969), CRC, Handbook of Chemistry and Physics, 49th Edition, (Dunning, 1981), Dunning, D. 8., et al; A Combined Methodology for Estimating Dose Rates and Health_Effects from Exposure to Radioactive Pollutants, Oak Ridge National Laboratories, 1980., (EPA, 1973), Assessment of the Potential Health Effects from Radon in Natural Gas; Office of Radiation Programs, USEPA, 1973, p. 5. (EPA, 1979, EPA Radiological Impact Caused by Emissions of Radio? nuclides into_the Air of the United States, Preliminary Raport, Washington. D.C., 1979. (FR, 1979), The Federal Register, Volume 44, NR Thursday, December 27, 1979 (FRL 1292?8). pp. 76738-76746. (Gessell, 1974), Gessell, T. Radiological Health Implications of Radon in Natural Gas and Natural Gas Products, a report to the University of Texas, health Science Center at Houston, School of Public Health, Houston, 1974. (Gessell, 1975), Gessell, T. F., and Pritchard, H. The Technologically En? hanced Radiation Environment, Health thsics, Volume 28 (April) 1975, pp. 361- 366. (ICRP, 1975), ICRP Publication 23; Report of the Task Group on Reference Han, Pergamon Press, 1975, p. 3&5; (ICRP, 1977), ICRP PublicatiOn 26, Recommendations of the International Com- mission on Radiological Protection, Pergamon Press, New York, 1977. (ICRP, 1980), ICRP Publication 30, Limits for Intakes of Radionuclides bx Yorkers, Pergamon Press, New York, 1980. EMLEI 0069456 32. (NCRP, 1975), Natural Background Radiation in the United States, National Council on Radiation Protection and Measurement. November 15, 1945, pp. 4, A7, 53. S4 and 57, and Figures 1, 2, and 3. (Pierce, 1964), Pierce, A. Gott, G. and Myton, J. Uranium and Helium in the Pan Handle Gas Field, Texas, and Adjacent Areas; USCS Profes? sional Paper 454?6, U.S. Government Printing Office, washington, D.C., 1964. (Rhodes6 1972), Rhodes, D. Comganz Memo, Reference 6252PHOO, Determination of,PbZl in Samples from Kuwait. (Sasser, 1978), Sasset, M. and Watson, J. An Evaluation of the Radon Con? centration in North Carolina Ground Water Supplies; Health Physics; Volume 34 (June), 1978, pp. 667?671. (Sullivan, 1981), Sullivan, R. al; Estimates of Health Risk from Ex- posure to Radioactive Pollutants; Oak Ridge Notional Laboratory, 7745, 1981. (Teknekton, 1981), "Draft", Technical Support for the Evaluation and Control bf EmiSSions of Radioactive Materials into Ambient Air, Teknekron Research Corp., Hay 1981. (UNSCEAR, 1977), United Nations Scientific Committee on the Effects of Atomic Radiation; Sources and Effects of Ionizing Radiation; United Nations, 1977, p. 12 and Annex B, Tables 35, 36, 38, 42 and 43. (USCGS, 1959), Uranium in Coal in the Western United States, Geological Bulletin 1055, Washington, 1959. (USDC, 1978), Analysis for Radionuclides in SRC and Coal Combustion Samples, Hittman Associates Inc., Columbia, Maryland, 1978, p. 11. (Wilson. 1982), Wilson, R., and Crouch, Risk/Benefit Analysis, Ballinger Publishing Company, 1982, Table 7?2. EMLEI 0069457