GCA-TR-75-32-GI10) ASSESSMENT OF ORTHO-XYLENE AS A POTENTIAL AIR POLLUTION PROBLEM VOLUME X FINAL REPORT Contract No. 68-02-1337 Task Order No. 8 Prepared For U.S. ENVIRONMENTAL PROTECTION AGENCY Research Triangle Park North Carolina 27711 January 1976 GCA TECHNOLOGY DIVISION BEDFORD, MASSACHUSETTS 01730 ------- CCA-TR-75-32-C(10) ASSESSMENT OF ORTIIO-XYLENE AS A POTENTIAL AIR POLLUTION PROBLEM Volume X by Robert M. Patterson Mark I. Bornstein Eric Garshick GCA CORPORATION GCA/TECHNOLOGY DIVISION Bedford, Massachusetts , January 1976 Contract No. 68-02-1337 Task Order No. 8 EPA Project Officer Michael Jones EPA Task Officer Justice Manning PROPERTY Or EPA LJD^ARY R7P, tlC U.S. ENVIRONMENTAL PROTECTION AGENCY Research Triangle Park North Carolina 27711 ------- This report was furnished to the U.S. Environmental Protection Agency by the GCA Corporation, GCA/Technology Division, Bedford, Massachusetts 01730, in fulfillment of Contract No. 68-02-1337, Task Order No. 8. The opinions, findings, and conclusions expressed are those of the authors and not neces- sarily those of the U.S. Environmental Protection Agency or of the cooperating agencies. Mention of company or product names is not to be considered as an endorsement by the U.S. Environmental Protection Agency. ------- ABSTRACT This report is one of a series which assesses the potential air pollution. impacts of 14 industrial chemicals outside the work environment. Topics covered in each assessment include physical and chemical properties, health and welfare effects, ambient concentrations and measurement meth- ods, emission sources, and emission controls. The chemicals investigated in this report series are: ' Volume I Volume II Volume III Volume IV Volume V Volume VI Volume VII Volume VIII Volume IX Volume X Volume XI Volume XII Volume XIII Volume XIV Acetylene Methyl Alcohol Ethylene Bichloride Benzene Acetone Acrylonitrile Cyclohexanone Formaldehyde Methyl Methacrylate Ortho-Xylene Maleic Anhydride Dimethyl Terephthalate Adipic Acid Phthalic Anhydride. iii ------- CONTENTS Page Abstract iii List of Figures v List of Tables v Sections I Summary and Conclusions 1 II Air Pollution Assessment Report 3 Physical and Chemical Properties 3 Health and Welfare Effects 3 Ambient Concentrations and Measurement 6 Sources of Ortho-Xylene Emissions 9 Ortho-Xylene Emission Control Methods 13 III References 18 Append ix A Ortho-Xylene Manufacturers 20 iv ------- FIGURE No. page 1 Estimated Installed Cost of Ortho-Xylene Storage Tanks (Equipment Costs Assumed to be the Same as Gasoline Storage Tanks) 17 TABLES 1 Significant Properties of Ortho-Xylene 4 2 Estimated Isolated Ortho-Xylene Consumption 1974 10 3 Average Composition of Mixed Xylene 11 4 Estimated Xylene Consumption - 1974 11 5 Sources and Emission Estimates of Ortho-Xylene - 1974 12 6 Estimated Installed Costs of Adsorption Systems 15 7 Estimated Annual Operating Costs of Adsorption Systems 15 8 Estimated Installed Costs of Thermal and Catalytic Incinerators 16 9 Estimated Annual Operating Costs of Thermal and Catalytic Incinerators 16 ------- SECTION I SUMMARY AND CONCLUSIONS Xylene is a colorless, flammable liquid having an aromatic odor similar to that of benzene and toluene. There are three isomers of xylene: ortho-, tneta-, and para-xylene. Commercial xylene is a mixture of the three forms with meta-xylene being the major component and ortho-xylene making up about 20.5 percent of the mixture. Ortho-xylene is produced solely for the manufacture of phthalic anhydride, while mixed xylenes are used as solvents, for the manufacture of xylene sulfonates and xylidenes, and as high octane components of gasoline. Data linking ortho-xylene exposure with health effects are lacking, due to the almost always concomitant benzene and toluene. Ortho-xylene is an irritant and narcotic at high concentrations, producing effects sim- ilar to alcohol intoxication. The NIOSH recommended standard for xylene is a time weighted average (TWA) exposure of 100 ppm for up to a 10-hour workday, 40-hour workweek, with a ceiling concentration of 200 ppm for 10 minutes. Simple diffusion modeling estimates place the likely maximum 1-hour average ambient concentration at about 0.5 ppm of ortho-xylene. The maximum 24-hour average ambient concentration might be expected to be about 0.3 ppm. About 1 billion pounds of isolated ortho-xylene were produced at nine locations in 1974, and production is expected to decline in 1975 before slowly increasing (6 percent growth by 1978). The primary emission ------- sources in descending order are mixed xylene solvent usage, mixed xylene production, ortho-xylene production and solvent usage, and bulk storage. Total emissions are estimated to have been about 184 million pounds in 1974. Although emission controls specifically for ortho-xylene are not reported, two types of controls are used extensively by the chemical industry to control hydrocarbon emissions. These are vapor recovery and incineration. Control by adsorption on activated charcoal is used when recovery is economically desirable. The primary advantage of incineration is that low concentrations may be oxidized with only small supplemental fuel requirements. Fixed roof storage tanks can be controlled by venting to an adsorber or to an incinerator, or they can be converted to floating roof design. Based on the results of the health effects research presented in this report, and the ambient concentration estimates, it appears that ortho- xylene as an air pollutant does not pose a threat to the health of the general population. In addition, ortho-xylene does not appear to pose other environmental insults which would warrant further investigation or restriction of its use at the present time. ------- SECTION II AIR POLLUTION ASSESSMENT REPORT PHYSICAL AND CHEMICAL PROPERTIES Xylene is a clear, colorless, flammable liquid having an aromatic odor similar to that of benzene and toluene. There are three isomers of xylene, ortho (1, 2 dimethyl benzene), meta (1, 3 dimethyl benzene), and para (1, 4 dimethyl benzene). Commercial xylene is a mixture of the three forms with meta-xylene being the major component. Ortho-xylene is the subject of this report. Commercial xylene is produced from both petroleum and coal tar. A typ- ical petroleum product contains approximately 20 percent ortho-xylene, while approximately 10 percent-15 percent of xylene manufactured from coal tar consists of the ortho isomer. Essentially all xylene in the U.S. is produced from petroleum. Ortho-xylene is predominantly used in the manufacture of phthalic anhydride. Significant physical properties are listed in Table 1.^ HEALTH AND WELFARE EFFECTS Effects on Man Acute Poisoning Xylene is an irritant to mucous membranes, and it is narcotic in high concentrations. Actual air concentrations have not, however, been reported when instances of acute poisoning have occurred. 2 In one instance three painters working in a ship's fuel tank were ------- overcome by xylene vapor from the paint they were using, in which the solvent was 90 percent xylene. The xylene concentration was estimated to have been 10,000 ppm. One of the men died shortly after discovery and an autopsy showed pulmonary edema and intra-alveolar hemorrhages. The other two men had temporary hepatic impairment and one had temporary renal impairment, but both recovered completely in two days. Table 1. SIGNIFICANT PROPERTIES OF ORTHO-XYLENE Synonyms Xylol, dimethyl benzene Chemical formula Molecular weight Boiling point Vapor density Solubility Explosive limits Flash point (closed cup) Autoignition temperature At 25°C and 760 mm Hg (CH3)2 106.16 143.6°C 1.024 (air = 1.0) Insoluble in water; miscible in alcohol, ether, and many organic solvents 17o-6% 17.2°C 501°C 1 ppm =4.34 mg/nf 1 mg/m3= 0.23 ppm Giddiness, anorexia (lack of appetite) and vomiting were observed in a 3 paint-pot cleaner who used a solvent containing 75 percent xylene. The remaining 25 percent was made up of ethylbenzene, methylethylbenzene, and trimethylbenzene. At head height above the pots the xylene concentration was 60 to 100 ppm when the pots were cold, and 270 to 350 ppm when they were warm. Higher concentrations were encountered when the painter placed his head inside the pots during cleaning. ------- For humans, only one report associates possible narcotic effects with a 4 known concentration of xylene. One of seven volunteers exposed to 230 ppm and one of six exposed to 460 ppm experienced slight lightheaded- ness without loss of equilibrium or coordination at the end of a 15- minute exposure period. Ingestion of xylene has caused acute injury of the liver. In one case a man mistakenly drank a small amount of nitrocellulose varnish, in which xylene was the main diluent, thinking it was water. He experienced immediate retro-sternal burning, heat and redness of the face, and some dyspnea (shortness of breath). Tests indicated toxic hepatosis with .* recovery in about three weeks. Liquid xylene is also a skin irritant, causing erythema, dryness, and defatting. Prolonged contact can cause blistering, but absorption through intact skin is not significant. Chronic Poisoning The NIOSH recommended standard for xylene is a time weighted average exposure of 100 ppm for up to a 10-hour workday, 40-hour workweek, with a ceiling concentration of 200-pom for 10 minutes. This standard is based mainly on the narcotic and irritant actions of xylene. Effects on Animals Acute Poisoning - The acute oral toxicity of xylene to animals is less than that of toluene or benzene. The oral LD _ has been given as 1.85 ml/kg. In white mice, narcotic effects have been noted at concen- trations of about 4000 ppm of ortho-xylene, with a lethal concentration iti 8 of about 7000 ppm. A concentration of 3062 ppm of ortho-xylene for 24 hours was fatal to some mice. Chronic Poisoning - Rats, guinea pigs, monkeys, and dogs were exposed to 770 ppm of ortho-xylene for 8 hours a day, 5 days a week for 30 days; 9 and to 78 ppm continuously for 90 days. At the end of the exposures ------- the animals were killed. Sections of heart, lung, liver, spleen, and kidney were taken from all species; sections of brain and spinal cord .were taken from dogs and monkeys. Results of microscopic examinations were negative and no significant changes were noted in body weight or hematologic data. Effects on Vegetation Tomato, barley, and carrot were exposed to xylene vapor at 1150 ppm for 1/4, 1/2, 1, and 2 hours. Barley was the most sensitive while carrots were least sensitive, based on percent injury and time of recovery. The * first noticeable symptom in all plants was a darkening of the tips of the youngest leaves, due presumably to a leakage of sap into the inter- cellular spaces. The darkening then spread to older leaves, and there was a loss of rigidity with drooping of stems and leaves. AMBIENT CONCENTRATIONS AND MEASUREMENT Ambient Concentration Estimates Although ortho-xylene emissions are greatest from the solvent usage source category, these sources tend to be small and geographically scattered. Production of ortho-xylene, however, occurs at a few loca- tions for which the emissions characteristics can be fairly well defined, and which as single point or area sources have a large emission density. The largest installation for isolated ortho-xylene production is located near Houston, Texas, a city of over one million population, and it has a capacity of about 210 million Ib/yr. Assuming a 0.5 percent loss, this converts to an emission rate of ------- (0.005 emission factor) (210 x IQ6 Ib/yr) (453.6 g/lb) 3.1536 x 107 sec/yr =15.1 g/sec of ortho-xylene. Some assumptions must be made regarding this ortho-xylene release to the atmosphere. First of all, the emissions do not all come from one source location, but rather from a number of locations within the plant where ortho-xylene vapor leaks to the atmosphere. Thus, the emissions can be characterized as coming from an area source which will be taken to be 100 meters on a side. Secondly, the emissions, occur at different heights, and an average emission height of 10 meters is assumed. Ground level concentrations can then be estimated at locations downwind of the facility. To do this a virtual point source of emission is assumed upwind of the facility at a distance where the initial horizontal dispersion coefficient equals the length of a side of the area divided by 4.3. In this case: o- = 100m/4.3 = 23.3si yo Assuming neutral stability conditions (Pasquill-Gifford Stability Class D) with overcast skies and light winds, the upwind distance of the virtual point source is approximately 310 meters. With consideration of the plant boundary, it is reasonable to assume that the nearest receptor location is thus about 500 meters from the virtual point source. Finally, taking 2 m/sec as an average wind speed, the ground level concentration may be calculated from: uircr ------- y ~.^ -% / 10 \ ; "• X'-tN.— y*^/-Nxi«-»r-\^ I ~-j"o C* J 15.1 (2) TT (36) (18.5) = 3.12 x 10"3 g/ra3 for a 10-minute average concentration. Over a period of an hour this becomes (3.12 x 10"3 g/ra3) (0.72) = 2.25 x 10"3 g/m3 or 0.5 ppm 1-hour average concentration. Over a 24-hour period, the average concentration might roughly be expected to be about 0.3 ppm. Ortho-Xylene Measurement Techniques Analytical methods for measuring ortho-xylene concentrations in air include ultraviolet absorption spectrophotometry, colorimetry, and gas chromatography. Air is either drawn through a bubbler or passed over silica gel or charcoal to remove the ortho-xylene from the air. Sensi- tivity, specificity, and accuracy are functions of the sampling method used and of the sampling interval. Features of the techniques are discussed below. 12 Ultraviolet Absorption Spectrophotometry - Ortho-xylene absorbs ultra- violet light at a wavelength of 272.0 mfi. Concentration may be determined by comparing the absorbance of the sample with the absorbance of known standards. In this technique air is collected in a gas washing bottle containing methanol, which is immersed in dry ice. After collection, the absorbance of ortho-xylene is determined on a spectrophotometer. This method is not/specific for ortho-xylene as other aromatic hydrocarbons will interfere and is not sensitive enough for air pollution work. The lower detection limit is about 10 ppm of ortho-xylene. 13 Colorimetric Method - In this technique air is collected in a special U-tube containing a solution of formaldehyde and sulfuric acid. After collection, the sample is transferred to a volumetric flask and diluted ------- with formaldehyde and sulfuric acid. The optical density of the color produced is read on a spcctrophotometer at 460 mpi. The concentration of the sample is then read from a calibration curve. Concentrations from 40 to 350 ppm may be determined by this method. Interferences will result from other aromatic hydrocarbons. This method is not sensitive enough for air pollution work but may be used for industrial hygiene work. 14 Gas Chromatography -aAdsorption of xylene vapor on activated charcoal with subsequent desorption and analyses by gas chromatograph is the pre- ferred sampling method for ortho-xylene. Concentrations in the range of 5 ppm are readily detectable by this method. Air is drawn through a tube containing charcoal on which organic vapors are adsorbed. The sample is then desorbed using carbon disulfide, and an aliquot of the desorbed sample is analyzed using a gas chromatograph. The presence and concentration of ortho-xylene are determined from its characteristic retention time and the area under the curve. Interferences may result from other organic compounds having similar retention times; however, this may be overcome by changing the operating conditions of the instrument, usually the column and/or the column temperature. This technique is especially well-suited for air pollution work since there is no requirement for special chemicals in the field. SOURCES OF ORTHO-XYLENE EMISSIONS Ortho-Xylene Production and Consumption The production of isolated ortho-xylene in 1974 was 1,045 million pounds and is expected to decli in growth during 1975 before slowly increasing (6 percent growth by 1978). ' ' Because of economic conditions during 1974 production of ortho-xylene far exceeded its demand (789 million pounds). The only ------- outlets for ortho-xylene are for phthallc anhydride, exports and miscel- laneous uses such as solvents for agricultural sprays. The difference between production and demand (256 million pounds) could not be accounted for even though conversations were held with several individuals in the 17 18 19 chemical industry. ' ' The only satisfactory explanation for the difference is that the ortho-xylene produced in 1974 was not all consumed and is being stored for future use when economic conditions improve.*0 Presently, there are nine companies at nine locations who isolate ortho- xylene from unmixed xylene (see Appendix A). The consumption of isolated ortho-xylene for final products is shown in Table 2. Table 2. ESTIMATED ISOLATED ORTHO-XYLENE CONSUMPTION 1974 Product Phthalic anhydride Exports Miscellaneous Increase in inventories Total Million pounds 667 117 5 256 1,045 Ortho-Xylene Sources and Emission Estimates In this report primary sources of emissions of ortho-xylene are estimated from both unisolated ortho-xylene present in mixed xylene streams, and from isolated ortho-xylene. Ortho-xylene is produced solely for the manufacture of phthalic anhydride; however, it is also a major component in mixed xylene streams. The composition of a typical mixed xylene has 21 been reported as shown in Table 3. Mixed xylenes are used primarily to produce the individual isomers, for solvent usage and for the manufacture of xylene sulfonates and xylidenes. They are also used as high octane components of gasoline. See Table 4. 10 ------- Table 3. AVERAGE COMPOSITION OF MIXED XYLENE 21 Toluene Ethylbenzene p-xylene m-xylene o-xylene c + aromatic 2.9% 23.7%. 16.77. 35.77. 20.57, 0.57. 100.07. Table 4. ESTIMATED XYLENE CONSUMPTION 197415'17'18)19>20>22 Product Million pounds 1. Mixed xylenes As a source of individual isomers Solvent usage Xylene sulfonates, xylidenes Blended into gasoline 2. Ethylbenzene 3. Ortho-xylene Phthalic anhydride Exports Miscellaneous solvent usage Inventory 4. Meta-xylene 5. Para-xylene 4,328 809 35 619 667 117 5 256 5,791 500 1,045 99 2,684 11 ------- Emissions of ortho-xylene result from mixed xylene solvent usage, mixed xylene production, ortho-xylene production, miscellaneous ortho-xylene solvent usage and bulk storage. Total emissions from all categories are estimated to be 184 million pounds with emissions from mixed xylene pro- duction and usage accounting for approximately 93 percent of all losses. See Table 5. Table 5. SOURCES AND EMISSION ESTIMATES OF ORTHO-XYLENE - 1974 Source Mixed xylene solvent usage Mixed xylene production Ortho xylene production Miscellaneous ortho-xylene solvent usage Bulk storage Million pounds 166 6 5 5 2 The major source of ortho-xylene emissions results from its use as a solvent present in mixed xylene (20.5 percent). The chief outlet of mixed xylenes in the solvent market is for industrial paints and thinners. It is assumed that all ortho-xylene used as a solvent will evaporate to the atmosphere. In 1974 an estimated 809 million pounds of mixed xylenes 22 were used for solvent purposes. Converting this figure to ortho-xylene will result in emissions of 166 million pounds. The second major source of emissions results from the manufacture of mixed xylenes. Ninety-nine percent of all mixed xylenes are recovered from petroleum sources and the rest are obtained as a by-product of coke- oven operations. Approximately 96 percent of the recovered xylene from petroleum sources is solvent extracted from reformate and the remaining 4 percent is solvent extracted from pyrolysis gasoline. 12 ------- Since there are no emission data available concerning these processes, 23 based on other similar processes, it is estimated that 0.5 percent of production is lost as mixed xylene resulting in 29 million pounds. Ortho-xylene emissions account for 20.5 percent of this total or 6 mil- lion pounds. The next major source of emissions is from the production of ortho-xylene, Using the same assumptions as above, 0.5 percent of production is lost resulting in 5 million pounds of ortho-xylene emissions. The fourth major source of ortho-xylene emissions is from miscellaneous solvent usage. Conversations with the industry have indicated that approximately 5 million pounds of ortho-xylene were used during 1974 as either a solvent for pesticide applications or as a solvent for other • ! • A 16,18 . specialized purposes. Aj evaporated to the atmosphere. •I /" -I Q specialized purposes. ' Again it is assumed that all solvent is The last primary source of emissions results from the bulk storage of ortho-xylene. Using the emission factors in AP-42 and assuming that all storage tanks are fixed roof tanks, 2 million pounds of ortho-xylene are 23 emitted from bulk storage tanks. 24 Data from a recent report on phthalic anhydride have indicated that emissions of ortho-xylene from this process are negligible. Based on this report, it is assumed that phthalic anhydride production is not a primary source of ortho-xylene emissions. ORTHO-XYLENE EMISSION CONTROL METHODS The literature does not report specific control equipment for ortho- xylene emissions, but it does report on control devices for other similar 25 hydrocarbons. Two types of control devices are presently used by the industry to control hydrocarbon emissions: vapor recovery and incineration. Both systems have reported efficiencies of at least 95 percent. 13 ------- Control of hydrocarbon emissions by adsorption on activated charcoal is generally applied when recovery of adsorbed material is economically desirable. Adsorption should be used when concentrations of hydrocarbons 9 fi are greater than 2500 ppm. Other applications are for the control of very low concentration hydrocarbons that are poisonous to catalytic in- cinerators and for collection and concentration of low concentration emissions for subsequent disposal by incineration. Cost data for the cases utilizing adsorption are presented in Tables 6 and 7. The three cases presented are adsorption with solvent recovery, adsorption with incineration, and adsorption with incineration plus heat recovery. Control of xylene emissions by incineration or catalytic oxidation in- volves direct oxidation of the combustible portion of the effluent, the desired ultimate products being water and carbon dioxide. The primary advantage of catalytic incineration is that extremely small concentrations of organics can be oxidized with only small amounts of supplemental fuel required. The main disadvantages are the higher capital cost and the poisoning of the catalyst by certain hydrocarbons. Cost data for thermal and catalytic incinerators with and without heat 27 recovery are presented in Tables 8 and 9. Control of emissions from storage tanks will require the use of floating roof tanks or venting the emissions to the previously mentioned adsorber or incinerator. Emissions from fixed roof tanks can be vented to either system without any major increase in cost. If these systems are not available the fixed roof tanks should be switched to floating roof tanks- resulting in a 67 percent reduction of emissions. Figure 1 provides 27 estimated costs of various gasoline storage tanks. " These equipment cost estimates can also be applied to ortho-xylene. As can be seen, conversion of fixed roof to floating roof tanks by installation of internal floating covers is more economical than the installation of new pontoon floating tanks. 14 ------- Table 6. ESTIMATED INSTALLED COSTS3 OF ADSORPTION SYSTEMS27 Adsorber capacity, SCFM - based on 25 percent lower explosive limit With solvent recovery, $ With thermal incinerator/ No heat recovery, $ With thermal incineration/ Primary heat recovery, $ 1,000 74,000 89,500 101,500 10,000 162,300 202,000 255,000 20,000 280,000 344,000 431,000 Costs updated to 1st quarter 1975. O ~7 Table 7. ESTIMATED ANNUAL OPERATING COSTSa OF ADSORPTION SYSTEMS Adsorber capacity, SCFM- based on 25 percent lower explosive limit With solvent recovery, $/yr With thermal incineration/ No heat recovery, $/yr With thermal incineration/ Primary heat recovery, $/yr 1,000 13,200 23,400 25,600 10,000 10,479b 64,300 82,000 20,000 37,200b 123,200 141,600 Costs updated to 1st quarter 1975. Indicates a savings. 15 ------- Table 8. ESTIMATED INSTALLED COSTS3 OF THERMAL AND CATALYTIC INCINERATORS27 Incinerator capacity, SCFM - based on 25 percent lower explosive limit Installed costs, $ Catalytic without heat recovery Catalytic with primary heat recovery Catalytic with primary and secondary heat recovery Thermal without heat recovery Thermal with primary heat recovery Thermal with primary and secondary heat recovery 1,000 43,500 54,100 68,300 27,200 , 40,300 54,400 10,000 272,000 306,000 361,800 92,500 144,200 200,000 20,000 504,600 573,900 666,400 137,400 232,600 322,300 Costs updated to 1st quarter 1975. Table 9. ESTIMATED ANNUAL OPERATING COSTS OF THERMAL AND CATALYTIC INCINERATORS2? Incinerator capacity, SCFM - based on 25 percent lower explosive limit Operating costs, $/yr Catalytic without heat recovery Catalytic with primary heat recovery Catalytic with primary and secondary heat recovery Thermal without heat recovery Thermal with primary heat recovery Thermal with primary and secondary heat recovery 1,000 16,200 16,400 19,300 12,000 11,500 14,400 10,000 102,800 78,500 108,700 54,300 36,300 50,800 20,000 195,000 177,900 203,700 96,700 59,200 84,500 Costs updated to 1st quarter 1975. 16 ------- 500 400 •o 300 r~ x O u 200 g z 100 T I I TT~1—T~T~1—T~T~T Total Coil Cono Roof Tank Converted with Internal floating Roof Pontoon Floating Roof Tank Cona Roof Tank Internal Float Cover on Existing Cona Roof Tonic (Incremental Cost - Conversion] Ol I f I I I I I I I I I I I f I I I I ? 0 50 100 150 200 CAPACITY, barrels x 1CT3 Figure 1. Estimated installed cost of ortho-xylene storage tanks (equipment costs assumed to be the same as gasoline storage tanks)27 17 ------- SECTION III REFERENCES 1. Am Ind Hyg Assoc J. Hygienic Guide Series. 32, October 1971. 2. MorleyR., D.W. Eccleston, C.P. Douglas, W.E.J. Greville, D.J. Scott, and J. Anderson. Xylene Poisoning A Report on One Fatal Case and Two Cases of Recovery After Prolonged Unconsciousness. Br Med J. 3:442-43, 1970. 3. Glass, W.I. Annotation: A Case of Suspected Xylol Poisoning. NZ Med J. 60:113, 1961. 4. Greenburg L., M.R. Mayers, L. Goldwater, and A.R. Smith. Benzene (Benzol) Poisoning in the Rotogravure Printing Industry in New York City. J Ind Hyg Toxicol. 21:395-420, 1939. 5. Browning, E. Toxicity and Metabolism of Industrial Solvents. Elsevier Publishing Co. (Amsterdam). 1965. 6. Occupational Exposure to Xylene: Criteria for a Recommended Standard. HEW Publication Number (NIOSH) 75-168. 1975. 7. Lazarew, N.W. On the Toxicity of Various Hydrocarbon Vapors. Arch Exper Pathol Pharmakol (Germany). 143:223-33, 1929. 8. Cameron, G.R., J.L.H. Paterson, G.S.W. de Saram, and J.C. Thomas. The Toxicity of Some Methyl Derivatives of Benzene with Special Reference to Pseudocumene and Heavy Coal Tar Naphtha. J Pathol Bacteriol. 46:95-107, 1938. 9. Jenkins, L.J. Jr., R.A. Jones, and J. Siegel. Long-Term Inhalation Screening Studies of Benzene, Toluene, Ortho-Xylene, and Cumene on Experimental Animals. Toxicol Appl Pharmacol. 16:818-23, 1970. 10. Currier, H.B. Herbicidal Properties of Benzene and Certain Methyl Derivatives. Hilgardia. 20:19, February 1951. 11. Turner, D.B. Workbook of Atmospheric Dispersion Estimates. U.S. Environmental Protection Agency Publication No. AP-26. April 1973. 18 ------- 12. Danbrouskas, T., and W. Cook. Methanol as the Absorbing Reagent in the Determination of Benzene, Toluene, Xylene and Their Mixtures in Air. Amer Ind Hyg Assoc J. 24.:568, 1963. 13. Hanson, N. , D. Reilly, and H. Stagg. The Determination of Toxic Substances in Air. W. Heffer and Sons, Ltd. 1965. 14. Occupational Exposure to Xylene. U.S. Dept. of Health, Education and Welfare. NIOSH. 1975. 15. Preliminary Report on U.S. Production of Selected Synthetic Organic Chemicals. U.S. International Trade Commission. May 16, 1975. 16. Chemical Profile, Chemical Marketing Reporter. May 26, 1975. 17. Conversation with ARCO, Houston, Texas. September 1975. 18. Conversation with Cosdon Oil and Chemical, Big Spring, Texas. September 1975. 19. Conversation with Shell Chemical Co., Houston, Texas. September 1975. 20. U.S. Exports Schedule B Commodity by County. U.S. Department of Commerce. December 1974. 21. Weedman, J.A., and R.A. Findlay. How to Separate Xylenes for Profit. Petroleum Refiner. November 1958. 22. Chemical Economics Handbook. Stanford Research Institute. September 1971. 23. Compilation of Air Pollution Emission Factors. U.S. Environmental Protection Agency Publication No. AP-42. April 1973. 24. Engineering and Cost Study of Air Pollution Control for the Petro- chemical Industry. Phthalic Anhydride Manufacture from Ortho- Xylene. U.S. Environmental Protection Agency Report No. 450/3-73-006-g. 25. Profitably Recycling Solvents from Process Systems. Pollut Eng. Hoyt Manufacturing Co., Westport, Mass. October 1973. 26. Lauber, J. The Control of Solvent Vapor Emissions. N.Y. State Department of Health. January 1969. 27. Hydrocarbon Pollutant Systems Study, Volume 1, MSA Research Corp. October 1972. 19 ------- APPENDIX A ORTHO-XYLENE MANUFACTURERS Arco Chevron Commonwealth Exxon Monsanto Phillips Shell Sun Tenneco Houston, Texas Richmond, California Panuelas, Puerto Rico Baytown, Texas Alvin, Texas Guayama, Puerto Rico Houston, Texas Corpus Christi, Texas Chalmette, Texas Total Annual capacity, million pounds 210 130 150 130 30 130 200 160 155 1,295 20 ------- |