Document e59BXDrgEepG5d05zo7mpj0mq

AMERICAN SMELTING AND REFINING COMPANY Department of Environmental Sciences Salt Lake City, Utah PLANT: El Paso FIELD WORK: C.E. Dungey J.B. Richardson SURVEY DATE: January 13-17, 1975 REPORT DATE: April 11, 1975 ENVIRONMENTAL SURVEY I. OPERATING - CONDITIONS The #3 blast furnace was down during the survey. Otherwise, operations were normal, however, certain operations were curtailed during the day to avoid SO2 violations. II. SAMPLING PROCEDURES A. One-hour sequential samples of airborne dust and fume were collected with A.I.S.I. tape samplers at seven specific locations: 1. Sinter Plant - Fire Floor - Feeder end between sinter machines #1 and #2. 2. Sinter Plant - Fire Floor - Feeder end between sinter machines #3 and #4. 3. Sinter Plant - Fire Floor - Discharge end of sinter machine #2. 4. Copper Reverberatory Furnace - Reverb Charge Deck - 15 feet southwest of slag charge port. '5. Copper Reverberatory Furnace - South of Reverb Near matte launder. 6. Copper Converters - Between converters #2 and #3 at control station. 7. Zinc Filming Furnace - Northeast side of furnace on steel support. -2- All samples collected were analyzed for lead and arsenic. In addition, copper plant samples were analyzed for copper, and samples collected near the zinc, fuming furnace were analyzed for zinc and copper. Analyses for lead, copper, and zinc were done by atomic absorption spectrophotometry. Arsenic was analyzed colorimetrically. B. Individual dust and fume samples were collected with M.S.A. personal monitors equipped with 0.8 micron pore size Millipore filter cassettes (plastic cover in place and inlet plug removed). These samples were also analyzed for lead, copper, zinc, and arsenic by the same methods described above. Two respirable dust samples (particles less than 10 microns) were collected with the M.S.A. pumps and a cyclone/filter assembly. C. DuPont audio dosimeters were used to record individual noise exposures in various areas throughout the plant. Memory cells in the dosimeters automatically integrated the worker's noise exposure and gave a readout in percent of the 8-hour timeweighted average of 90 dBA. One dosimeter was used that recorded exposure over 85 dBA. D. Sulfur dioxide samples were collected using the M.S.A. personal monitor equipped with a midget impinger and pre-filter. The absorbing solution was 3% hydrogen peroxide. Analysis was per formed by the Shell Development titration method. E. Carbon monoxide measurements were taken near the blast furnaces and in the blast furnace baghouse clean-out area using a M.S.A. "Model D" portable CO-sampler. F. Laboratory hood ventilation measurements were made with an Alnor thermoanemometer. G. A composite sample of dust was collected from railings on the second floor of the mill. It will be used to determine the percentage of free silica in this area. ') -3- III. SAMPLING RESULTS A. A.I.S.I. Tape Samplers: Department Location Start- ' ing No. of Date Hourly (1975) Samples Analysis Mean Concentration (mg/nr) Max. Min. Percent Exceeding OSHA Graph Limit No. Sinter Feeder end Plant between sinter machines #1 and #2 1/13 . 24 Pb 1.34(c) As<b) 0.049 3.55 0.119 0.09 0.009 79 0 1 -- Feeder end , 1/14 between sinter machines #3 and #4 18(a) Pb 1.45 As (**) 0.041 2.91 0.073 O'. 30 ` 0.009 100 0 2 -- Discharge 1/15 end,sinter machine #2 24 Pb 1.77(c) As(b) 0.059 4.01 0.147 0.16 0.011 92 0 3 -- Copper Reverb Reverb charge deck 1/13 24 Pb 0.10 As ^ 0.30 0.20 1.81 0.04 0.04 0 13 -- -- Cu 1.28(d) 4.18 0.56 67 (dust) 4 100(fume) --* Near matte 1/14 launder 22 Pb 0.08 0.29 As<b> 0.060 0.112 Cu 0.35(e) . 0.71 0.02 0.015 0.17 5 -- 0-- 0 (dust) --100 (fume) -- Copper Between Con- #2 and #3 verter Converters 1/15 24 Pb 0.13 As<b> 0.016 Cu 0.29(e) 0.81 0.040 1.73 0.02 <.008 0.04 17 5 0 4 (dust) 6 75 (fume) -- Zinc Northeast Fuming side Furnace 1/16 17 Pb 0.22(c) 0.69 Zn 0.44 3.43 0.02 <.04 35 7 (f) (ZnO fume) As<b) 0.065 Cu 0.19(e) 0.25 0.56 <.008 0.01 0-- 0(dust) -- 59(fume) -- A.I.S.I. Tape Samplers (cont.) FOOTNOTES AND EXPLANATIONS: (a) Tape sampler averaged 70 minutes per spot instead of the customary one hour. (b) OSHA is currently proposing a more stringent 8-hour time-weighted average for arsenic of 0.004 mg/m3. All average and most hourly arsenic concentrations would violate such a proposed standard. (c) Mean exceeds OSHA 8-hour time-weighted average (TWA) concentration for lead. (d) Mean exceeds OSHA 8-hour time-weighted average for copper dust. (e) Mean may exceed OSHA limit for airborne copper fume. However, tape samplers cannot separate fume and/or dust particles. Further sampling would be needed to determine compliance with the copper fume standard. (f) OSHA has a standard for ZnO fume of 5.0 mg/m^. It does not specify a limit on Zn or ZnO dust. The laboratory can only detect for elemental zinc. The : amount of ZnO fume in the sample is'* some unknown percentage of the total amount. PRESENT ,0SHA LIMITS: Pb ZnO fume Cu dust Cu fume As 3 0.2 mg/m 5.0 mg/m3 1.0 mg/m3 0.1 mg/m3 0.5 mg/m3 B. Personal Monitors Depart- Employee Name ment and Number Job or Operation Shift* Sampling 1975 Time Date (Min). Analysis Conc'n. (mg/m3) Mill g Car Unloader D 1/17 176 Pb 0.09 Cu 0.09 As 0.009(e) Total Particulate 1.92 Cs V 'hg*i Gyratory Feeder ^ D 1/17 181 Pb 0.21(a) Cd 0.01 As 0.016(e) Total Particulate 9.41 Gyratory . Feeder D 1/14 \ 252 (Gross sample invalid -- pump failed) (Respirable sample) Pb Cd As Respirable Particulate 0.03 <.005 <.005 2.03 Symmonds Feeder 4- D 1/14 251 Pb 0.21 Cd 0.008 As 0.021(e> Total Particulate 142(afd) Ore Bins #24 Beltman t i- 1/14 268 Pb 0.61(a> Cd 0.03 As 0.066(e) Total Particulate 95.4(a,d) Sinter Plant \ D & L q(f\ Feeder ' M 1/15 262 Pb '"* Cd As 1.38(a) 0.06 0.056(e) DSL 3/; M 1/15 252 Pb 48.89(a'd) v Beltman Cd 0.78(afb,d) As 2.53(a/d,e) DSL Final Fireman j,-. M 1/15 258 Pb Cd AS 0.63(s) 0.04 0.028(e) B. Personal Monitors (cant.) Department Sinter Plant Employee Name and Number : ' Job or Operation * Shift' D & L First Fireman & , \ \\ M Sampling 1975 Time Date (Min) Analysis 1/15 256 Pb Cd As Blast Furnace Blast Furnace M 1/15 282 Pb * Charge Floored Cd As Conc'n. _ (mg/in3) 0.90{a> 0.06 0.035(e) 1.18 (aJ 0.30(a) 0.053(eJ tg Blast Furnace Baghouse '& -- #1 Fumaceman D Fork Lift Operator M Dust Puller D \0-' 1/14 > 233 Pb Cd As 0.49 0.03 0.023(e) 1/15 264 Pb C\ ! ' Cd As 0.81(a) 0.10 0.032(e) 1/16 223 Pb Cd As 4.06(a) 3.10 0.19(e) (Respirable Sample) Pb Cd As Respirable Particulate 1.12{a> 1.09(at) 0.058(e> 12.26(a) ' V Lead Dross Reverb *.*y- V Payloader Operatory/" Tenant Sweeper , ,,,g Operator Dross Reverb Molder ' ' Bucket Craneman t, ~ \ Respirable Fraction: Pb = 28% - Cd = 35% As = 31% D 1/16 219 Pb Cd As D 1/16 211 Pb Cd As D 1/14 232 Pb : .!* \> Cd As E 1/16 181 Pb Cd As 14.29(a) 10.29(a,b) 0.53(a'e) 0.94(a) 0.09 0.035(e) 0.90(a) 0.03 0.022 (e) 1.54(a) 0.009 , 0.17(e) B. Personal Monitors (cont.) 7 Depart- Employee Name ment and Number Job or Operation * Shift Sampling 1975 Time Date (Min) Analysis Conc'n. (mq/m3 ) Wedge Boasters M s? Feeder Feeder E 1/16 179 Pb 0.07 Cd <.007 Cu 0.63 As 0.043<e) E 1/16 171 Pb 0.09 Cd O.OO^ Cu 0.37lc; As 0.02 e' 55?: Fire Floor ^ E 1/16 170 Pb 0.07 Operator ' Cd 0.006 Cu 1.25 As 0.053<e) Copper Reverb Larry Car D 1/17 171 Pb 0.06 Switchman - Cd <.008 Cu 1.95(a) As 0.047(e) Larry Car , Motorman v" ^ D 1/17 172 Pb 0.09 Cd <006 Cu 1.50(a) As 0.05(e) Matte Tapper J E 1/15 \wc. 212 Pb 0.06 Cd <005 Cu 0.38(e) As 0.05(e) Slag .E 1/15 213 Pb 0.05 Skimmer if'U Cd 0.005 1 Cu 0.13(c) As 0.033(eJ Converter Waste Heat Boilerman D Skimmer on #3 E Skimmer on #2 ... E 1/17, r~ 154 1/15 " 233 1/15 227 Pb 0.05 Cd <.008 Cu 0.19() As 0.054{e) Pb 0.15 Cd 0.005 Cu 0.12(c) As 0.015(e) Pb 0.23(a) Cd 0.006 Cu 0.43 (<") As 0.035 (e) B. Personal Monitors (cont.) 8- ' Depart-. Employee Name ment______ and Number Converter Job or Operation Shift Tuyere c>; Puncher *' E Zinc Fuming Furnace Crane ^ Chaser l'-"' E >y-r: So.Craneman E > ^ ar v Tapper ' D i Furnace L D l Helper Zinc jV*>' > ) Boiler Man r> \'V D Operator D Loader \^ D D Laborer D (unloading^ ) dust) \ Sampling 1975 Time Date (Min) 1/15 *i ! T`:.7,, 233 1/15 214 1/15 227 1/16 C-i- 204 1/16 278 1/16 207 1/15 279 1/15 287 1/15 283 1/15 283 Analysis Conc'n. (mg/m3) Pb 0.28 (a) Cd 0.008 Cu 5.01(a) As 0.04(e) Pb 0.15 Cd 0.005 Cu 0.53 (c) As 0.042(e> Pb 0.42(a) Cd 0.03. , Cu 0.45(C) As 0.069 (a) Pb 0.28(a) Zn 0.80 , Cu 0.65{c) As 0.052(e) Pb 0.65(a) Zn 2.19 Cu 0.29(c) As 0.059(e> Pb 0.41(a) Zn 2.36 Cu 0.26 As 0.044(e) Pb 0.25 (a) Cd 0.008 Zn 0.91 As 0.018(e) Pb 0.45(a) Cd 0.009 Zn 1.76 As 0.026 Pb 0.15 Cd <.004 Zn 0.29 As 0.008 6 Pb 33.5(a) Cd 0.03 , Zn 14.8lf) As 0.106 e I -9- B. Personal Monitors (cont.) Department Employee Name and Number Job or Operation Shift* Sampling 1975 Time Date (Min) Anal ysis Conc'n. (mg/m3) Cadmium Unloading Crane and Payloader \\ Operator Cadmium Godfrey Roasters Fireman . <: r 'j * Shift Code: D = Day E = Evening M = Midnight D D 1/15 3 .* 289 1/15 278 Pb Cd As Pb Cd Zn .As 0.98 0.74(a'b 0.064 (e) 0.45(a) 0.009 1.76 0.026(e) (a) Exceeds present OSHA 8-hour time-weighted average for either lead, arsenic, cadmium dust, copper dust, ZnO fume, or total/respirable particulate (see table of standards below). (b) Exceeds OSHA acceptable ceiling concentration for cadmium dust. (c) May exceed OSHA limit depending upon nature of material, i.e. dust and/or fume exposure. (d) Probable "salted"sample. v 3 (e) Exceeds proposed OSHA time-weighted average for arsenic of 0.004 mg/m . (f) OSHA has a standard for ZnO fume of 5.0 mg/m3. It does not specify a limit on Zn or ZnO dust. The laboratory can only detect for elemental zinc. The amount of ZnO fume in the sample is some unknown percentage of the total amount. PRESENT OSHA LIMITS: Material 8-hour timeweighted average Acceptable Ceiling Conc'n. (Not to be exceeded at any time during an 8-hour shift Pb Cd dust Cd fume Cu dust Cu fume As ZnO fume Total Particulate Respirable Particulate PROPOSED OSHA LIMIT: ' 0.2 mg/m; 0.2 mg/m 0.1 mg/m 1.0 mg/m; 0.1 mg/m; 0.5 mg/m; 5.0 mg/m; 15.0 mg/m; 5.0 mg/m` As 0.004 mg/m3 o 0.6 mg/m 0.3 mg/m3 Acceptable Ceiling Conc'n. (Not to be exceeded during any 15-minute period) 3 0.01 mg/m 1 -10- C. Audio Dosimeter Noise Survey: The percent exposure given by the readout unit has been adjusted for an eight-hour working period using thefollowing formula: Readout % Exposure 8-hour working _ Adjusted Sampling x Period ~ % Exposure Period 1. 90 dBA Standard (used by OSHA) Dfepart- Employee ment Name & No. Mill Blast Furnace Convert : ter W ' 32$- Sampling 1974 Time 115 dBA Job Description Date (Min.) Exceeded Sample Train Laborer 1/14 246 No Ore Unloading (with shaker) 1/14 240 Yes #1 Furnaceman 1/14 233 Yes % Exposure Readout Adjusted" 39 76 4> * 158 316 ** 64 132 #3 Skimmer 1/15 236 No 31 63 Tuyere Puncher 1/15 226 Yes 64 136** Crane Chaser 1/15 233 Yes 12 25 Anode Furnace Refiner 1/15 200 Yes 2. 85 dBA Standard (advocated-by EPA to OSHA) Anode Furnace #1058 Molder 1/15 206 No 26 62 137 319' * The dosimeter records any level over 115 dBA during the exposure period. ** Exposures exceeding 100% may violate the OSHA 90 dBA standard, assuming the adjusted percent readout exposure correctly reflects the sound levels that would be received for an 8-hour period. OSHA, however, usually does not cite unless they exceed 120%. + Exposures exceeding 100% may violate an 85 dBA standard, if adopted by OSHA. -llr D. Sulfur Dioxide Sampling: Stationary Location Job or Department or Employee Operation Sampling 1975 Time Date (Min.) Concentration (PPM S02) (Over Sampling Period) Wedge Roaster Feed Floor between #1 and #3 Roasters Stationary 1/16 149 4.2 Feed Floor between #1 and #3 Roasters Stationary 1/16 124 0.3 Copper Reverb (resp. worn) Larry Car Switchman 1/16 152 23.4 Charge deck, 15 ft. SW of slag charge port Stationary 1/16 152 13.1 Charge deck, 15 ft. SW of slag charge port Stationary 1/16 119 1.5 Converter #1 control panel Stationary 1/16 84 < .07 * OSHA standard (8-hour time-weighted average)'*.......... 5.0 ppm E. Carbon Monoxide Measurements: Area Location Conc'n. at time of Sampling (PPM CO) * Blast Furnace #1 Furnace #2 Furnace Charge Deck None Det (1 II Blast Furnace Baghouse Clean-out Tunnel 1st door from north end 5' from door 15' from door 40 40 2nd door from north end 51 from door 60 3rd door from north end 21 from door - 10' from door 15' from door 100 75 50 -12- E. Carbon Monoxide Measurements; Area Location Conc'n. at time of Sampling (PPM CO) Blast Furnace Baghouse Clean-out Tunnel 4th door from north end 10' from door 5th door from north end 2' from door 10' from door 75 120 60 7th door from north end 5' from door 151 from door 160 80 11th door from north end (workers cleaning out this area) 5' from door At doorway 10* inside door 70 120 80 * OSHA Standard (8-hour time-weighted average) ... 50 ppm F Laboratory Hood Ventilation: Area Umpire Lab Plant Lab Exhaust Hood Hood #1 Hood #2 Hood #3 Hood #4 Hood #6 Hood #7 Hood #8 H2S Hood SO2 Hood Hood #1 Hood #1 Assay Hood Near Opening Near Table 'v Average Face Velocity (fpm)* 175 160 150 175 200 135 140 100 35 130 130 150 35 * Minimum acceptable face velocity for lab hoods 100 fpm -13- IV. COMMENTS A. Mill Area and Ore Bins: Two of the personal monitor samples collected in the mill area exeeded the OSHA 8-hour standard for lead. Materials being crushed during the sampling periods were mostly silica rock and coke; therefore, airborne lead values might be higher on days when lead ores are processed. Although excessive airborne dust was not observed during the survey, high particulate concentrations were found in the work area of the Symmonds feederman. This value (142 mg/m^) may be a "salted" sample but much of the particulate matter may be coke of silica, because of the operations that day. Accumulations of settled dust were noted on the railings and floor throughout the Mill. This dust can be stirred up by activity in the area and may contribute to excessive airborne lead and dust concentrations. An improvement in general house keeping would probably help reduce airborne lead and particu late levels. The #24 beltman in the Ore Bins area also worked in high con centrations of lead and total particulate. Again, these values may be suspect, because of the excessive particulate concen tration. Dustiness in this area should be investigated by the El Paso Safety Department, and the employee resampled to check the dust concentrations found during this survey. An audio dosimeter placed on an employee unloading ore cars indicates that the noise exposure is unacceptably high for the four hours sampled. If this exposure should continue for a full shift, it would be 316% above the OSHA 90 dBA standard for an 8-hour day. Administrative or engineering controls should be utilized to remedy this situation. One possibility is total or partial enclosure of the car shaking operation . Another solution would be to install a sound booth, which employees could use to avoid noise when not working at their stations. .Management personnel should make sure that adequate hearing protection is always worn by 'employees unloading ore cars. B. Lead Plant: All tape and personal monitor results show airborne concen trations above the OSHA limit for lead in each area sampled throughout the Lead Plant. In addition, cadmium-in-air values were high for employees who wore samplers on the Blast Furnace Charge Floor and in the Blast Furnace Baghouse. -14- Because a new Lead Plant will be built in the near future, extensive engineering controls will be de-emphasized at this time. However, reduction of airborne lead exposures should continue to receive high priority.' Good respirator wearing and improved general housekeeping practices should be emphasized. It is possible that the sample obtained from the D & L beltman is a "salted" sample. However, the airborne lead concentrations in this area probably exceed the OSHA standard. A personal monitor sample from last year's survey indicated a concentration of 3.60 mgPb/m3 for this operation. Respirator wearing should be strictly enforced by supervisory personnel in this area. Fumes evolved in tapping slag and lead from the blast furnaces appeared to be captured well by the hooding provided. Personal monitor results, however, indicate that airborne lead levels are still above OSHA limits. The high lead concentrations might be caused by leaks from other points around the blast furnaces, blowover from the Sinter Plant, or dust stirred up by activity in the area, such as forklifts, etc. Again, good general housekeeping practices can help reduce lead-in-air concentrations. No carbon monoxide was detected in this area. As mentioned in previous reports, lead concentrations in the vicinity of the Dross craneman need to be reduced. Serious con sideration should be given to the possibility of pressurizing the cab or operating the crane from the ground by remote control. Attention should be given to full utilization of hood ventilation for the dross kettles. It was observed during the survey that the duct extending from the dross hood was not connected to the flue system (see photo). Levels of airborne lead and cadmium were high for the two workers cleaning out bins in the blast furnace baghouse tunnel. A res pirable sample indicates that general dust levels were also in excess of the OSHA standard. Extensive carbon monoxide measure ments made in the baghouse tunnel were also above the OSHA limit. Workers in this area wore cartridge respirators, which provide no protection against carbon monoxide. A Type "N" canister gas mask would provide protection against both dust and carbon monoxide. In addition, the plant safety department should frequently spot check for levels of carbon monoxide in this area. The noise dosimeter placed on the blast furnaceman indicates that noise levels may exceed the OSHA 90 dBA standard for this opera tion, if they continue for an eight-hour period. Burner and tuyere punching noise are probably the main sources of high noise levels. The plant safety department should make certain that employees involved in this operation wear hearing protection. -15- Copper Plant: Most lead concentrations in the Copper Plant were below the OSHA limit, except in the Converter Department (where three out of five personal monitor samples exceeded the standard). In addition, a personal monitor, placed on a tuyere puncher wearing a respirator, indicates a copper dust concentration five timeis above! the! acdeptable limit. Tape samples collected between converters #2 and #3 suggest that lead levels may be acceptable near the control stations. Respirator wearing appeared to be good in this department. A sulfur dioxide impinger worn by a larry car switchman indicated a concentration of 23.4 ppm SO2 during a portion of his work period (the OSHA standard is 5 ppm). On the reverb charge deck (where the larry car operators spend part of their time), one of two SO2 impinger samples was also excessive. Personal monitor samples show that copper dust concentrations for the operators were also above the OSHA limit. Respirator wearing by these men was observed to be good. However, the plant safety department should make sure that these employees are using NIOSH-certified chemical cartridge respirators', that are effective for both sulfur dioxide and dust. Sulfur dioxide impinger samples collected on the Wedge Roaster Feeder Floor were acceptably low. Although the roaster occasionally emits fugitive SO2, no immediate problem^is foreseen because of the natural ventilation in the open building. However, employees should be encouraged to wear respirators in visible dust and/or fume. Past surveys have shown noise levels to exceed the OSHA 90 dBA standard for the tuyere punchers and the anode furnace area. Audio dosimeters placed on workers in these areas confirm past results. The plant.safety department should make certain all of - these employees are included in the hearing conservation program. If the proposed OSHA 90 dBA standard is promulgated, all employees exposed to 85 dBA or more would have to be given annual audiograms. The dosimeter placed on the anode molder set up to record noise levels over 85 dBA, indicates that this man works in an area qualifying him for routine audiometric testing. Employees should wear hearing protection when working in all of these areas. In general, employees seemed to display a lax attitude about wearing hearing protection in noisy areas. Workers cleaning out matte and slag launders with air hammers- in the reverb area were observed not to be wearing hearing protection. Employees should not only be issued hearing protection, but should be instructed about the importance of using muffs or plugs. Immediate supervisors, such as foremen, should set a good example by wearing hearing protection, and enforcing its use by their crews. -16- D. Zinc Fuming Furnace: All tape and personal monitor results show concentrations above the OSHA limit for lead in this area. The slag pot may be one source of these airborne lead levels. During the survey, the hooding apparatus over the pot did not appear to function well. Fumes were observed escaping from the hood into the surrounding environment (see photo). Ventilation should be improved to capture all of the emissions. E. Zinc Plant; High airborne lead concentrations are still a problem in this department. Three employees sampled worked in areas with lead levels over the OSHA limit. The sample collected in the zinc office shows that the airborne lead level is acceptable. During the survey, fugitive emissions were noted in the zinc kiln area, although it could not be determined at the time where the sources were. The sources of these emissions should be investigated by the plant engineer and the El Paso Safety Department and elim inated, to help reduce lead concentrations. A personal monitor sample indicates that the airborne lead concentration in the vicinity of the laborer unloading East Helena dust was 33.5 mgPb/m^ (far above the OSHA limit). Besides enforcing good respirator wearing, the plant engineer and safety department should seek additional ways to help reduce this man's exposure to lead. One possibility might be isolation of the employee from dust concentrations inside the building while he is watching the unloading operation. An open platform could be erected outside the building, where he could view car shaking activities through a clear window. This employee should also be resampled soon to verify the high lead concentration. Sampling equipment is available from the Department of Environmental Sciences. F. Cadmium Plant; Both personal monitor samples collected from this department exceed the OSHA standard for lead. The crane operator's sample also exceeded the OSHA limit for cadmium. Because of the high airborne concentrations of lead and cadmium in the work area of the craneman, it has been recommended in past reports that an air line respirator be provided for this man. This is still regarded as a feasible solution to help reduce his lead and cadmium exposure. Because part of his time-is spent running a payloader, this would require the installation of a compressed air tank on this machine. -17- Airborne lead concentrations in the vicinity of the fireman still need attention. Leaks in the roaster on the fire floor or dust stirred up by wind or human activity in the area are possible sources of these concentrations. The plant engineer ing department should investigate the possibility of leaks in the roaster. Occasional wetting-down of the area outside the roaster building as well as good housekeeping practices inside could help reduce airborne lead dust concentrations. G. Laboratory; 1. Plant Lab Face velocity measurements indicate that ventilation is adequate for capturing fumes near the opening of the assay hood. However, ventilation is not adequate near the table where cupels are placed to cool after being removed from the muffle furnaces. The hood should be extended closer to the table where cupels are placed. 2. Umpire Lab Ventilation measurements show that most of the lab hoods have adequate face velocities. However, the SO2 hood should be rebuilt. It is possible that the fan may be corroded after years of use with SO2. In the Assay Room, fumes from cooling cupels were observed to engulf the entire workroom area. A slot exhaust hood should be installed near the table to draw fumes away from the worker. H. Proposed Arsenic Standard: To determine El Paso's compliance with the possible new OSHA arsenic standard, each tape and personal sample was analyzed for arsenic. All of the samples exceed the proposed 8-hour timeweighted average of 0.004 mg/m3, except for possibly eleven samples, which were all below 0.008 mg/m3 -- the lower limit of detectability for such samples at this time. I. Biological Monitoring; In 1974, there was a total of seven employees with either con firmed high blood and/or urine lead levels. In 1975, one addi tional employee has been confirmed to have a high blood lead value. Out of these eight employees, four were D & L beltmen. One man was a D & L fireman. These findings stress the need for observ ing good respirator-wearing practice in the D & L work areas. -18- J. Free Silica: Compliance with the OSHA standard for free silica depends on the percentage of free silica in a .dust sample, weighing one gram or more. The amount of dust collected on a personal monitor filter cassette is too small for free silica analysis. Because airborne free silica concentrations in the Mill are currently needed, a composite sample of settled dust was collected from various railings. The percentage of free silica found in this dust sample will be assumed to be the same for dust collected on a personal monitor cassette filter. At the writing of this report, a free silica analysis for the dust sample had not yet been completed. When the results are received, they will be included as an addendum to this report. V. RECOMMENDATIONS' A. An evaluation of nuisance dust exposures in the Mill should be made. The Department of Environmental Sciences can advise the El Paso Safety Department concerning the procedures for such an evaluation. Employees found to work in excessive particulate concentrations should be resampled soon (under close supervi sion to reduce the incidence of salted samples) to verify the samples on this survey. .An improvement in housekeeping practices may help reduce airborne dust levels. B. Administrative or engineering controls of the car shaking opera tion should be utilized to reduce noise exposure to the ore unloader. Possibilities include total or partial enclosure of the operation or a sound booth. C. Reduction of airborne lead exposures in the Lead Plant should continue to receive top priority. Good respirator wearing and general housekeeping practices should be adherred to. In this regard, particular attention should be given to D & L beltmen. D. The feasibility of operating the dross crane from the ground via remote control, or pressuring the cab, should be investigated by Central Engineering. E. The duct extending from the dross hood to the exhaust flue should be connected for full benefit of the existing ventilation system. F. Workers in the blast furnace baghouse tunnel should wear Type "N" canister gas masks that provide protection against both carbon monoxide and dust. G. The use of hearing protection in noisy areas needs to be more strictly enforced by supervisory personnel. -19- H. Hooding over the Zinc Fuming Furnace slag pot needs better enclosure and more air volume to improve its ventilation efficiency. I. The sources of emissions from the zinc kilns should be investi gated by the El Paso Engineering and Safety Departments. J. Additional protection, besides a respirator, needs to be found for the laborer unloading East Helena dust. An open platform erected outside the building, where he could view car shaking operations through a clear window might be one possibility in reducing his dust exposure. However, this job activity should . be resampled to verify the excessive lead concentration found on this survey. K. The cadmium crane operator should be wearing an air line respira tor to minimize exposure to excessive lead and cadmium concentra tions in this area. L. Occasional wetting down of the area outside the Godfrey Roaster building might help reduce airborne lead concentrations in the vicinity of the fireman. The plant engineer should investigate the possibility of leaks from the roaster in the fire floor area M. The SO2 hood in the Umpire Lab needs to be upgraded. N. In the Umpire Lab, a slot exhaust hood should be installed near the table in the Assay Room. O. . The assay hood in the Plant Lab should be extended closer to the table to provide better ventilation for the cupels. Curtis E. Dungey Environmental Specialist CED/bj s Enel. cc: WRKelly KDLoughridge DHSoutar KWNelson AJGillespie,Jr./JPStetson LCTravis RCBeckstead EHHaug Dr.CHHine vrfovarner 12 M Time of Day 12N 4.0 3.0 2.0 1.0 12 N A irb o rn e Lead (m g/m 3 ) . A irb o rn e Lead (m g/m A irb o rn e C opper (m g/m 3 ) A ir b o r n e L e a d (in g /m 12N 6 12M 6 Time of Day 12N A irb o rn e Lead (m g/m 3 ) A irb o rn e C opper(m g/m I Zinc Emissions from Fuming Furnace Slag Pot Dross Hood in Background. <^nnt leading to Sampling for SO2 in Wedge Roaster Building with Impinger Assembly Crane unloading dust in Cadmium Department