Document 4QJM0Jd6w38E0XKJk0yzJ902x

LABORATORY NO.: CHARGES: SUBJECT: CONOCO INC. PONCA CITY, OKLAHOMA REFINING TECHNICAL SERVICES LABORATORY Pic.; PC File: 662.1 924 Date: 9/4/84 1-5-84 PC 49 Summary of Benzene Content of Finished Gasolines and In-Plant Streams - 1977 to 1984 - Ponca City Refinery CONCLUSION: No* Ponca City Refinery finished gasolines or in--plant streams contain as much as 10.0 vt.Z benzene. Therefore, the control provisions of EPA regula tion 40 CFR 61, Subpart J, do not apply. DISCUSSION: A recently promulgated regulation from EPA mandates controls on benzene fugitive emissions at petroleum refineries. A key definition in the regu lation is: "In benzene service means that a piece of equipment either con tains or contacts a fluid that is at least 10 percent benzene by weight as determined according to the provisions of 161.245(d)." Unless fluids pro duced or used in the refinery contain at least 10 wt-Z benzene, the controls in the regulation do not apply. At R. L. Thorstenberg*s request of 8/29/84, the results of previous labora tory studies of benzene in Ponca City Refinery streams are summarized in this report. Five major studies on this topic were made from 1977 through 1984. Benzene content of all the streams measured in them was lover than 10 wt.Z. Attachment II is a laboratory crosscheck comparing benzene concentrations determined using gas chromatography and infra-red analytical methods. The benzene results Included in this report were obtained using both methods at different times. The method described in the regulation at 61.245(d) is gas chromatography. ANALYTICAL DATA: Attachment I. REFERENCE: 1. Memo from R. L. Thorstenberg to R. S. Jones, dated 8/29/84. 2. Several laboratory reports dated in 1977, 1980, and 1984. Approved: > cc: GAO-RLT-EW-PLY-RSJ-KCH-F Att: 2 LABORATORY NO.: 1-5-84 9/4/34 ftCfarhmpnr I. Attachment I Benzene Content of Ponca City Refinery Finished Products and In-Plant Streams Stream Description Finished Gasolines Regular Gasoline Unleaded Gasoline Super Unleaded Gasoline Regular Gasoline Unleaded Gasoline Super Unleaded Gasoline Regular Gasoline Unleaded Gasoline Regular Gasoline Premium Gasoline Unleaded Gasoline Regular Gasoline Premium Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Premium Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Premium Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Premium Gasoline Premium Gasoline Unleaded Gasoline Conotane Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Unleaded Gasoline Regular Gasoline Premium Gasoline Regular Gasoline Premium Gasoline Unleaded Gasoline Regular Gasoline Regular Gasoline Regular Gasoline Premium Gasoline Regular Gasoline Premium Gasoline Sample Date 7/84 7/84 7/84 2/84 2/84 2/84 7/80 7/80 1/80 1/80 1/80 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5/77 5'77 5/77 5/77 3/77 0P 0V *> Benzene Wt.Z 1.3 1.1 0.6 1.0 0.7 0.4 1.3 0.7 1.4 l.X 0.9 1.1 0.5 1.0 1.1 1.3 0.4 1.2 0.8 1.3 0.3 1.1 1.3 0.8 1.0 1.0 1.1 0.4 0.7 0.7 1.3 1.0 1.3 1.0 0.7 1.3 0.7 1.0 0.2 0.7 1.1 1.3 1.0 0.3 1.0 0.7 MORATORY NO. : 1-5-84 9/4/84 Attachment 1 (Continued) Page 2 Attachment I (Cont * d) Stream Description Finished Gasolines (cont Regular Gasoline Unleaded Gasoline Jet Fuels JP-4, military Q-Grade, commercial In--Plant Streams -- 05 FCC Lt. Gasoline #5 FCC Hvy. Gasoline 04 FCC Lt. Gasoline 04 FCC Hvy. Gasoline 02 Reformer Charge 02 Reformer Reformate (94 RON) Alkylate 03 Reformer Charge 03 Reformer Reformate (97 RON) Straight Run Gasoline Coker Gasoline Cat Poly Gasoline -- 05 FCC Lt. Gasoline 05 FCC Hvy. Gasoline -- 04 FCC Lt. Gasoline 04 FCC Hvy. Gasoline 02 Reformer Charge 02 Reformer Reformate (89.5 RON) Alkylate 03 Reformer Charge 03 Reformer Reformate (87.7 RON) 03 Reformer Reformate (97.3 RON) Straight Run Gasoline Regular Coker Gasoline Cat Poly Gasoline Casinghead Gasoline Regular Coker Gasoline Premium Coker. Gasoline Cat Poly Gasoline 04 FCC Lt. Gasoline 04 FCC Hvy Gasoline -- 05 FCC Lt. Gasoline 05 FCC Hvy. Gasoline Alkylate 02 Reformer Charge Sample Date . 3/77 3/77 6/77 5/77 7/84 7/84 7/84 7/84 7/84 7/84 7/84 7/84 7/84 7/84 7/84 7/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 2/84 7/80 7/80 7/80 7/80 7/80 7/80 7/80 7/80 7/80 7/80 Benzene Wt.Z 1.2 0.7 0.1 <0.1 1.0 0.3 0.8 <0.1 0.2 ' 2.3 <0.1 0.2 3.9 1.3 0.1 <0.1 1.1 0.4 1.0 <0.1 0.22.0 0.3 0.42.7 4.5 1.4 0.1 <0.1 0.5 0.2 0.4 <0.1 1.3 0.1 1.1 0.2 <0.1 A 0.2 - MCD 000019291 LABORATORY NO.: 1-5-84 9/4/84 Attachment L (Continued) Page 3 Attachment II(ContM) Stream Description In-Plant Streams (cont'd) 02 Reformer Reformate (89.4 RON) $3 Reformer Charge #3 Reformer Reformate (89.5 RON) Straight Run Gasoline Straight Run Gasoline Casinghead Gasoline Regular Coker Gasoline Premium Coker Gasoline Hydro-treater Gasoline Cat Poly Gasoline --#4 FCC Lt. Gasoline #4 FCC Evy. Gasoline ~05 FCC Lt. Gasoline 05 FCC Hvy. Gasoline Alkylate 02 Reformer Charge 02 Reformer Reformate (90 RON) 03 Reformer Charge 03 Reformer Reformate (90 RON) 02 Reformer Reformate #3 Reformer Reformate Total Alkylate Casinghead Gasoline 1 CTO Raw Crude North Texas 02 CTU Raw Crude West Texas and Foreign #4 CTU Raw Crude Oklahoma-Kingfisher 05 CTU Raw Crude West Texas and Foreign. 02 Reformer Reformate Straight Run Gasoline Cat Poly Gasoline #5 FCC Gasoline - 05 FCC Lt. Gasoline 05 FCC Hvy. Gasoline Coker Gasoline #4 FCC Hvy. Gasoline --#4 FCC Lt. Gasoline 03 Reformer Charge 03 Reformer Reformate Straight Run Gasoline Sample Date 7/80 7/80 7/80 7/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 1/80 10/77 10/77 7/77 7/77 6/77 6/77 6/77 6/77 5/77 5/77 5/77 5/77 4/77 4/77 4/77 4/77 4/77 4/77 4/77 4/77 Benzene Wt.% 1.9 0.2 2.0 1.2 1.3 0.7 0.2 0.5 0.2 <0.1 1.1 <0.1 1.2 0.1 <0.1 0.1 1.2 0.5 3.1 -- 1.8 ' 1.9 <0.1 0.5 0.1 <0.1 0.1 0.1 1.3 1.3 <0.1 0.6 0.6 0.6 0.1 <0.1 0.4 0.2 1.5 1.8 0\92.9^ OOO ( ^ CONOCO INC, PONCA CITY, OKLAHOMA REFINING TECHNICAL SERVICES LABORATORY W*ce Pit. : File: Date: PC & LC 610.3 10/31/S LABORATORY NO. : CHARGE: SUBJECT: J-103-30, PC 49, LC 49 Polynuclear Aromatic Analysis of Coker Feed - Ponca City and Lake Charles Refineries. ANALYTICAL DATA: Sample No.: Sample: PC 1 564 LC 649 Vacuum Jug Bttms Lake Charles Benzene Solubles, wt.%* 99+ Polynuclear Aromatics, wt.% 2.0 Sample No.: PC 1570 LC 655 Vacuum Resid. Lake Charles Benzene Solubles, wt.%*- 99+ Polynuclear Aromatics, wt.% 3.1 PC 1565 PC 1567 LC 650 LC 652 Ethelene Monsanto Hvy Aromatics Tar Lake Lake Charles Charles < 99+ 99+ 4.2 20.6 PC 1572 LC 657 FCC Slurry Oil Lake Charies PC 1821 -- Vacuum Resid Ponca City 99+ 39.1 99+ 1.1 PC 1568 LC 653 Shell Tar Lake Charles 99+ 14.8 PC 1822 -- Decant Oil Ponca City 99+ 33.9 PC 1569 LC 654 Thermal Tar Lake Charles 99+ 38.2 PC 1823 -- DuoSol Extract Ponca City 99+ 0.3 * The polynuclear aromatics of the benzene soluble fraction , as determined by a liquid chromatographic (HPLC) system in the R&D Analytical Research Section, in- eludes all 3 and greater membered-ring-type PNA compouncfs. REFERENCE: Letter from 0. R. Barresi to K. C. Hunt dated 9/9/80. }rh cu-^i a c<tl Analytical Chemist MCD 0019426 Senior Technologist bp cc: ORB-LHB-WF-MJ-KCH-F & 2-1^2-000/ received NOV J , IjuO k3 Refy Pers P.C, VII. APPENDIX I METHOD FOR SAMPLING AND ANALYTICAL PROCEDURES FOR DETERMINATION OF BENZENE The following sampling and analytical method for analysis of benzene in air employs adsorption on charcoal, followed by desorption, and gas chromatographic measurement. This is a modified method derived from White et al [136] and Kupel and White. [137] Additional data are contained in Part IV under Sorbability of Benzene on Charcoal and Accuracy and Precision Data. Atmospheric Sampling (a) Equipment Used The sampling train is composed of a charcoal tube, a vacuum pump, and a flowmeter. A personal sampler pump or a dependable hand pump, eg, a detector tube pump may be calibrated to produce the desired volume of air. (b) Calibration of Sampling Instruments Air sampling instruments may be calibrated with a wet test meter or other suitable reference over a normal range of flowrates and pressure drops. The calibration is conducted at least annually and at any time following repairs or modifications to the sampling system. Similarly, wet test meters should be calibrated upon procurement, at least annually, and after each repair. Calibration curves shall be established for each sampling pump and shall be used in adjusting the pumps prior to field use. The volumetric flowrate through the sampling system shall be spot checked 93 HOP 000019855 and the proper adjustments made before and during each study to assure obtaining accurate airflow data. (1) Flowmeter Calibration Test Method (A) With the wet test meter in a level position, check to ascertain that the water level just touches the calibration point on the meter. If the water level is low, add water 1 to 2 F wanner than room temperature to the fill point and run the meter for 30 minutes before calibration. (B) Check the voltage of the pump battery with a voltmeter to assure adequate voltage for calibration. Charge the pump battery if needed. (C) Break the tips of a charcoal tube to produce openings of a least 2 mm in diameter. (D) Assemble the calibration train in series, with the test meter, then the charcoal tube, and finally the pump. (E) Turn the pump on, adjusting the rotameter float to a selected reading on the rotameter scale. Wait until the float indicates a steady reading. (F) The pointer on the meter should turn clockwise and indicate a pressure drop of not more than 1.0 inch of water. Operate the system for 10 minutes before starting the calibration. If the pressure is greater, recheck the system. (G) Data for the calibration include the serial number; meter reading, start and finish; starting time, finish time, and elapsed time; air temperature; barometric pressure; serial number of the 94 sP op o,0Lo% pump and rotameter; the name of the person performing the calibration; and the date. (H) Adjust the rotameter float to at least 3 other readings and record the pertinent data in step G at each reading. (I) Correct the readings to standard conditions of pressure and temperature by means of the gas law equation. (J) Use graph paper to plot the actual airflow and the rotameter readings. Determine the rotameter reading which will result in a 1 liter/minute flowrate for the pump being calibrated. (c) Sampling Procedure The equipment should be set up in a proper locale. The tips of the charcoal tube are broken off producing openings of at least 2 ran in diameter; the filled end of the tube is inserted toward the pump. The tube should always be in a vertical position during sampling. The pump is started and a 10-liter sample is taken at a flowrate of 1 liter/minute. Slower flowrates may be used to lengthen the sampling period but Che 1 liter/minute rate should not be exceeded. After the sample is taken, each end of the tube should be capped (plastic caps are provided with commercial tubes). The samples will remain stable for at least 2 weeks which permits shipment for analysis; however, samples should be analyzed as soon as possible in keeping with good laboratory practices. Analytical (a) Principle of the Method A known volume of air is drawn through a charcoal tube to trap the organic vapors present. The charcoal in the tube Is transferred to a small 95 test tube and desorbed with carbon disulfide and an aliquot of the desorbed sample is injected into a gas chromatograph. The area of the resulting peak is determined and compared with areas obtained from the injection of standards. (b) Range and Sensitivity The lower limit for benzene with instrument attenuation and splitter techniques is 0.01 mg for each sample. This value can be lowered by reducing the attenuation or by eliminating the splitter. The upper limit value for benzene is 6.0 mg/sample. This value is the number of milligrams of benzene which the front section will collect before a significant amount passes to the backup section. The charcoal tube consists of 2 sections of activated charcoal separated by a section of urethane foam [see description in (f)(2)]. If a particular atmosphere is suspected of containing a large amount of contaminant, it is recommended that a smaller than normal sampling volume be taken. (c) Interferences (1) When the amount of water in the air is so great that condensation actually occurs in the tube, organic vapors will not be trapped. Only water present as a mist is a problem, not water vapor. (2) Any compound with the same retention time in the gas chromatograph as benzene at the operating conditions described in this method could be considered an interference. This type of interference can be overcome by changing the operating conditions of the instrument. -96 MOD 000019858 (d) Accuracy and Precision The accuracy and precision determined by a representative laboratory test with benzene (see also Accuracy and Precision Data in Part IV) was found to be: Accuracy Precision Motor driven laboratory pump 7.6% 4.2% Approved coal mine personal sampling pump (calibrated with no in-line resistance) 13.6% 10.1% Approved coal mine personal sampling pump (calibrated with charcoal tube in line) 8.8% 11.6% The accuracy includes single-day systematic error by 1 operator. Precision represents the single-cay accuracy on several different tubes and includes tube-to-tube ceviation under controlled laboratory conditions. [138] (e) Advantages and Disadvantages of the Method The sampling device is small, portable, and involves no liquids: one basic method is provided for determining many different organic solvents. Interferences are minimal and most can be eliminated by altering chromatographic conditions. In addition, the analysis is accomplished using a rapid instrumental method. 97 000019869 One disadvantage of the method is that the amount of sample which can be obtained is limited by the amount of benzene which the tube will hold before overloading as indicate^ by benzene recovery at the outlet end of the tube. Also, the precision is limited by the reproducibility of the pressure drop across the tubes, which affects the flowrate, thus causing the volume to be imprecisely measured. (f) Apparatus consists of: (1) An approved coal mine dust personal sampling pump or any vacuum pump whose flow can accurately be determined at 1 liter/minute or less for an area sample. (2) Charcoal tubes: Glass tubes with both ends flamesealed, 7 era long with a 6-mm O.D, and a 4-mmI.D., containing two sections of 20/40 mesh activated charcoal separated by a 2-mm portion of urethane foam. The absorbing section contains 100 mg of charcoal, the backup section, 50 mg. A 3-ram portion of urethr.r.e foam is placed between the outlet end of the tube and the backup section. A plug of glass wool is placed in front of the absorbing section. The pressure drop across the tube must be less than 1 inch of mercury at a flowrate of 1 liter/minute. Tubes with the above specifications are commercially available. (3) Gas chromatograph equip?ed with a flame ionization detector. (4) Column (20 ft x 1/8 in) v:_th 10% FFAP stationary phase on 80/100 mesh acid washed DMCS Chromosorb W solid support. (5) A mechanical or electronic integrator or a recorder and some method for determining peak area. (6) Small glass-stoppered test tubes or equivalent tubes. 9-8 MCD 000019860 (7) Syringes: 10 yl syringe, and other convenient sizes for preparation of standards. (g) Reagents s. (1) Spectroquality carbon disulfide (2) Benzene, preferably chromatoquality grade. (3) Bureau of Mines Grade A heLiu.n. (4) Prepurified hydrogen. (5) Filtered compressed air. (h) Procedure (1) Cleaning of Equipment All equipment used for the labo,:a.:ory analysis should be washed in detergent followed by tap and distilled wa:er rinses. (2) Collection and Shipping tf Sa:;.p.^es Both ends of the charcoal tube t.te buo-en to provide openings of at least 2 mm (one-half the I.D. of the tube). Tie smaller section of charcoal in the tube is used as a backup sec';:.on .u-. i is, therefore, placed nearest the sampling pump. Tubing may be used to ^c-mect the back of the tube to the pump, but no tubing must ever be glared on the front of the charcoal tube. Because of the high resistance of th charcoal tube, the sampling method ' places a heavy load on the personal sampling pump; therefore, it should not be assumed that the pt:mp ^ill run a full 8 hours without a recharging of the battery. One or more charcoal tubes serving as blanks are treated in the same manner as the sample tubes (break, setl, ship) except that no air is drawn through them. _ 99 MOD 000019861 If bulk samples are submitted in addition to charcoal tubes, they are to be shipped in a separate container. (3) Analysis of Samples J. (A) Each Preparation charcoal tube i i is scored with a file and broken open in front of the first section of charcoal. The glass wool is removed and discarded, the charcoal in the first (larger) section is transferred to a small stoppered test tube, the foam separating sec,:ion is removed and discarded, and the second section is transferred tc a other test tube. The two charcoal sections are then analyzed separately. (B) Desorption Prior to analysis, 0.5 ml o' carbon disulfide is pipetted into each test tube to desorb the benzenefrom the charcoal. Desorption is complete in 30 minutes if the sample isstirred occasionally. EXTREME CAUTION MUST BE EXERCISED A' ALL T'l.ES WHEN USING CARBON DISULFIDE BECAUSE OF ITS HIGH TOXICITY AND FIRE AND E:CPLOSION HAZARDS. IT CAN BE IGNITED BY HOT STEAM PIPES. ALL WORK WITH CA ;B0N DISULFIDE MUST BE PERFORMED UNDER AN EXHAUST HOOD. (C) Gas chromatographic conditions Typical operating condi:Ions for a gas chromatograph are: (i) 85 cc/min (70 psig) helium carrier gas flow. (ii) 65 cc/min (24 psig) hydrogen gas :low to detector. (iii) 500 cc/min (50 psig) airflow to detector. (iv) 200 C injector temperature. (v) 200 C manifold temperature (detecior). 100 00 (vi) 90 C oven temperature isothermal. (vii) Use either dual column differential operation or uncompensated mode. (D) Injection To eliminate difficulties arising from blovback or distillation within the syringe needle, tie solvent flush injection technique is employed to inject the sample into the gas chromatograph. The 10--a<1 syringe is first flushed with solvent several times to wet the barrel and plunger, then 3 yl of solvent is drawn into the syringe to increase the accuracy and reproducibility of the injected sample volume. Next, the needle is removed from the solvent and the plunger is pulled back about 0.2 Ml to separate the solvent flush from the sample with an air pocket to be used as a marker. The needle is then immersed in the sample and a 5--1 aliquot is withdrawn. Prior to injection in the gas chromatograph, the plunger is pulled back a short distance to minimize sample evaporation from the needle tip. Duplicate injections should be made of e'ach sample and the standard. No more than a 3% difference shculd result in the peak areas that are recorded. (E) Measurement of aret The area of the sample poa-: is measured by an electronic integrator or some other suitable form of area measurement and preliminary sample results are read from a standard curve prepared as outlined below. - 101 MCD 000019863 (i) Standards Preparation and Desorption Efficiency (1) Preparation of Standards It is convenient to prepare standards in terms of mg/ 0.5 ml of carbon disulfide because this is the quantity used for benzene desorption from the charcoal. To prepare a 0.3 mg/ 0.5 ml standard, 6.0 mg of benzene (converted to microliters for easy measurement) is injected into exactly 10 ml of carbon disulfide in a glass-stoppered flask. The excess quantity of benzene is used to minimize error due to carbon disulfide volatility. A series of standards is then prepared, varying in concentration over the desired range, and analyzed under the same gas chromatographic conditions and during the same time period as the unknown samples. Curves are established by plotting concentration vs average peak area. (2) Determination of Desorption Efficiency The desorption efficiency, ier the percentage of benzene desorbed from the charcoal, is determined only once, provided the same batch of charcoal is always used. Activated charcoal, equivalent to the amount In the first section of the sampling tube (100 mg), is measured into a 2-in, 4-mn T.D. glass tube, flame-sealed at one end, and capped w;th a paraffin film or equivalent at the open end. A known volume of benzene, usually equivalent to that present in a 10-liter sample at a concentration equal to the federal standard, is injected directly into the activated charcoal with a microliter syringe and the tube again capped Jith pore paraffin film. A minimum of 5 tubes are prepared in this manner aid allowed to stand for at least 1 day to assure complete adsorption of the benzene onto the charcoal. 102- 000019864 These Cubes are desorbed and analyzed in exactly the same manner as the sampling tubes. The results of each analysis are compared to the standards to determine the average percentage (desorption efficiency) that is desorbed.. The desorption efficiency is then used as a factor in all sample analyses. The desorption efficiency, determined in this manner, has been shown to be essentially the same as that obtained by analysis of a known amount of benzene vapor trapped on the charcoal and the determined value, therefore, is used because of its simplicity. Each laboratory should determine its own desorption efficiency. For comparison purposes, NIOSH determined a value of 96% for benzene on one batch of charcoal. (j) Calculations (1) Read the weight in milligrams corresponding to each peak area from the standard curve. No correction is necessary for the volume injected, since it is the same for both tie sanole determination and the standard curve. (2) The weight of benzene ci the front section of the blank is subtracted from the weight determined for the front section of each sample; a similar procedure is follcwed for. the backup sections. Amounts present on the front and backup sectiov.s of the same tube are then added together to determine the total amount cetectec. `n the sample. This total weight is then divided by the desorption efficiency to determine the corrected total number of milligrams in :[ e sample. Milligrams are converted into ppm by volume in the air sampled by tlu following equation at 2 5 C and 760 mm Ilg: 103 WCD 0000^8e5 ppm = 24,450 ml/mole x mg/liter molecular wc For a 10-liter air sample of benzene: ppm = 24,450 ml/mole x mg in sample/10 liters 78,11 g/mole ppm = 31.30 x mg in sample 104 Oo019e 66 VIII. APPENDIX II METHODS FOR DETERMINATION OF EXPOSURE AREAS TO BENZENE Estimation of Concentration with Detector Tubes (a) Atmospheric Sampling (1) Equipment Used A typical sampling train consists of a detector tube with a corresponding sampling pump. A specific manufacturer's pump may only be used with his detector tubes. (2) Sampling Procedures A specific procedure depends c-n the manufacturer's instructions but normally consists of breaking both tips off a detector tube, inserting the tube into the pump, and caking a specific number of strokes with the pump. (3) Handling and Shipping ofSamples Detector tubes are not stable w:.th time; the stain in some tubes fades in a few minutes. The tubes should be read immediately in accordance with the manufacturer's instructions and charts; no attempt should be made to save the used tubes. (b) General Principles Gas detector tubes contain a chemically impregnated packing which indicates the concentration of a contaminant in the air by means of a chemically produced color change. The color changes are not permanent or stable, so the stained tubes must be read immediately after the samples arr> taken. The length of stain or the color intensiiy is read according to the IT) 5 MCD 000019867 manufacturer's instructions. This may involve comparing the stain with a chart, a color comparator, or a direct concentration reading from calibration marks on the tube. Detailed descriptions are provided by individual manufacturer's instructions. Tubes obtained from commercial sources which bear the certified seal of NIOSH are considered to adhere to the requirements as specified for Approval of Gas Detector Tube Units in 42 CFR Part 84 (37 F.R. 19643). A user may perform his own calibration on commercially acquired tubes by generating accurately known concentrations of benzene in air and cor relating concentration with stain length or color Ln.iensity. (c) Range and Sensitivity Certification standards require that certified tubes have a range from 1/2-5 times the time-weighted average concentca:ion. The sensitivity varies with tube brands. (d) Interferences Interferences vary with tube brands. The manufacturer's instructions must be consulted. (e) Accuracy Certification standards by NI,OSH under vhe provisions of 42 CFR Part 84 (37 F.R. 19643) specify reliability to within 25% of the actual concentration in the range 0.75-5 times the stancard and 35% in the range from 0.5 up to, but not including, 0.75 times the standard. (f) Advantages and Disadvantages Unlike the charcoal tube method, tie use of detector tubes (and portable instruments) is relatively inexpensive and rapid; there is far less time lag than that experienced with laboratory analytical results. 000019868 Rapid detecting units are valuable for determining whether a hazardous condition exists at a given location so that workers may be evacuated or suitable protective devices provided. In addition, industrial operators and process engineers need inexpensive and rapid tools for day-to-day evaluation of the atmospheric levels in a work area. The accuracy of detector tubes is limited; at best they give only an indication of the contaminant concentration. In evaluating measurements performed with detector tubes, interferences, difficulty of end-point readings, and possible calibration inaccuracies must abi be considered. Measurement with Portable Instruments (a) Atmospheric Sampling (1) Equipment Used Two classifications of portable meters tnat are applicable to atmospheric sampling are direct reading instruments and analytical instruments. Combustible gas meters and flame ionization meters are portable, direct reading instruments; portable variable-path infrared analyzers and gas chromatographs are both field analytical Instruments. Any of the 4 meters mentioned are acceptable for benzere determinations if they are properly calibrated before use. (2) Sampling Procedures The most important sampling stop is t \e meter calibration. Careful calibration must be performed either in rhe laboratory prior to on site use or in the field using a container .f specific benzene concentration. If calibration charts are inaccurate, erroneous readings will be made. 1Q7 MCD 000019869 The actual field sampling is conducted according to the manufacturer's instructions. Readings should he corrected, if necessary for j. variables such as temperature, humidity, atmospheric pressure, etc, and recorded along with time, place, temperature, etc. (b) General Principles Analysis is dependent on the type of meter used. The portable direct reading meters require no analysis because they usually provide usable concentration readings directly. Results obtained from the variable-path infrared analyzer and the gas chromatograph must be recorded, further analyzed, and compared with standards to obtain concentration values. (c) Range and Sensitivity The range and sensitivity vary with the instrument used; in general, the portable analysis meters are more sensitive than cirect reading units. (d) Interferences Again, these vary with the instrument used. Water vapor or combustible gases interfere with benzene identificaticn using combustible gas meters. Mixtures of any carbon containin'; compounds, other than benzene, will interfere in flame ionization determinations. (e) Advantages and Disadvantages The benefits and drawbacks of portable instruments are essentially the same ns for detector tubes discussed previously. Where recording capability is possible, direct reading instruments have the advantage of continuous record availability. 108 MCD 000019870 IX. APPENDIX III BIOLOGIC METHOD FOR SAMPLING AND ANALYSTS'OF BENZENE The recommended biologic method for urinalysis is derived from Sherwood and Carter. [102] It has been designee- to determine the concentration of phenol and its conjugates, sjlfate and glucuronide, in urine. It also determines orthocresol and meta- and paracresols. Urine is hydrolyzed with perchloric acid at 95 C, and the phenols and cresols are extracted with isopropyl ether and determined by gas chromatography. Collection of Urine Samples "Spot" urine specimens of about 100 ml aie colie :ted as close to the end of the working day as possible. If any woiker's urine phenol level exceeds 75 mg/liter* procedures are instituted immediately to determine the cause of the elevated urine phenol levels and to redact benzene exposure to the worker. Weekly specimens are collected as described above until 3 consecutive weekly determinations indicate that urinary phenol levels are below 75 mg/liter. After thoroughly washing their hands v:th 30cp and water, workers shall collect urine samples from single voidings in -Lean, dry specimen containers having tight closures and at least a 120-ml capacity. Collection containers may be glass, waxcoated paper, cr other disposable types if desired. Following collection of urire spe.imens, 1 ml of a 10% copper sulfate solution is added to each sample as preservative, and samples are immediately stored under refrigeiution., preferably at 0-4 C. 109 MCD 000019871 Refrigerated specimens will remain stable for approximately 90 days. If shipment of samples is necessary to perform analyses, the most rapid method available shall be employed utilizing acceptable packing procedures as specified by the carrier. Proper identification of each specimen shall include as a minimum, the worker's name, date, and time of collection. Analytical (a) Principle of the Method Urine samples are treated with perchloric acid at 95 C to hydrolyze the phenol conjugates, phenyl sulfate, and phenyl glucuronide, formed as detoxification products following benzene absorption. The total phenol is extracted with diisopropyl ether and the phenol concentration is determined bv gas chromatography analysis of the diisopropyl et\er extract. (b) Apparatus (1) Gas chromatograph with a flame onization detector and equipped with a 5-foot x 3/16-inch column packed witi 2 w/w polyethylene glycol adipate on universal 'B' support. Operating conditions are as follows: Column temperature 110 C Detector temperature 2)0 C Injection port tempera ture Carrier gas 2 )0 C Nitrogen Carrier gas flowrate 6) ml/min (2) Water bath (3) Glass-stoppered, 10-ml volumetric flasks -LL0 MCD 000019872 (4) 1-ml, 2-ml, and 5-ml volumetricpipets (5) 5-^1 syringe (c) Reagents ' (1) Phenol (2) Perchloric acid (3) Diisopropyl ether (4) Distilled water (d) Procedure (1) Hydrolysis of Phenol Conjugates Pipet 5 ml of urine into a 10-ml, glass-stoppered, volumetric flask. Add perchloric acid, mix by swirling, and transfer the lightly stoppered flask to a water bath at 95 C. Aftar 2 hours, remove the flask from the water bath and allow to cool at room temperacure. (2) Diisopropyl ether extraction of ohenol and cresols. Pipet 1 ml of diisopropyl ether into tha flask and adjust the volume to 10 ml with distilled water. Shake vigorously for l minute to extract the phenol and cresols. Allow the aqueous and ether layers to separate. (3) Gas chromatographic analysis for phenol Inject 5 of the diisoprcpyl ether layer into the gas chromatograph and record the attenuation and area of the phenol peak. Under the conditions described, phenol is eluced in 100 seconds, orthocresol in 130 seconds, and roeta- and paracresols in 320 seconds. Ill MCD 000019873 (e) Standards Preparation A 50 mg/liter standard aqueous solution of phenol is prepared. A 5ml aliquot of the standard solution is then subjected to the hydrolysis, extraction, and gas chromatographic analysis procedures described under Procedure above. (f) Calculations Determine the phenol concentration in the urine by comparing the gas chromatographic peak area of the sample with that of the 50 mg/liter standard and adjust the value to a specific gravity of 1.024. (g) Specific Gravity Correction Due to the magnitude of correction which is required, samples having uncorrected specific gravities less than 1.010 shall be. rejected and another sample shall be obtained. Based on a survey of a large poelation in the United States in connection with urinary lead excretion, Levure and Fahy [139] found the mean specific gravity to be 1.024. Many investigators throughout the world now use this figure. Buchwald [130] in 196<> determined the mean specific gravity for residents in the United Ki.rgdom to be 1.016, a value now frequently used for Northern Europeans. Thr importance of specific gravity adjustments can be seen in that a specific gravity of 1.016 will give results having two-thirds the value of those corrected to 1.024. It is important, therefore, that a value be chcsen for standardization; since greater acceptance seems to be for 1.024, this valve has been selected for adjustment of urinary concentrations of benzene recommended for biological monitoring. corrected concentration = _______ observed concentration x 24 ' last 2 digits of sp gr (eg, 1.021) 112 ,019874 hcd 000 X. APPENDIX IV SPECIAL MEDICAL CONSIDERATIONS The literature on the subject of benzene intoxication, both acute and chronic, has been reviewed elsewhere in this document. Levels of exposure permitted in the standards set by this document have been shown to reduce the danger of acute intoxications to a minimum. [1,24,23] Barring accidental exposure, the need for constant monitoring for signs and symptoms of acute intoxication is unnecessary The toxic effects of chronic low level exposures are not as well documented and, as has been discussed, exposures to 40 ppm have caused hematologic changes in animals. [66] The need for constant and complete monitoring of the organ systems known to be affected by chronic benzene exposure is, therefore, prudent and necessary. The hematologic system is especially singled out by benzene's toxic effects. There is no agreement in the literature as to which parameter of hematologic function is the first indicator of early benzene intoxication. Monitoring a number of components, therefore, becomes necessary. The life span of the erythrocyte has been calculated by various methods to be approximately 120 days. [140] Thii means that if erythrocyte production were to stop suddenly, as in the development of aplastic anemia, 0.83% of the red cell mass would be lost daily. In the asymptomatic individual exposed to very low concentrations j.r benzene, measurements of the red cell mass could safely be done every 3 months. In workers exposed to higher concentrations, the risk of developing aplastic anemia increases, and more frequent determinations become necessary. In the event cf red 113 000019876 cell agenesis, 2 weeks would be a sufficient time to reduce the red cell mass by 12%. A longer delay in discovering this condition would be deleterious to the prognosis; thus, monitoring the red , individuals with higher levels of exposure to benzene should ceil mass in be done at intervals not exceeding 2 weeks. Macrocvtosis has also been stated to be the second most frequent toxic effect of benzene on the bone marrow (140): therefore, bone marrow monitoring for macrocytosis by the measurement of appropriate corpuscular indices at the most frequent practical period is indicated. No such simple means for estimating the decay of the white blood cell mass in the case of WBC agenesis is available because, to date, the life span of neutrophils has not been measured successfully, despite estimates of less than 12 days. [140] It is difficult to rationally set a maximum period beyond which it would be dangerous to delay measurement. Quarterly intervals in exposed individuals are felt to be maximum intervals prudent in this situation, reflecting the expense and difficulty of the differential WBC count, but measurement at shorter intervals is desirable where practical. The life span of platelets has been variously estimated as from 9-12 days. These data are imprecise because of the difficulty inherent in the measurements. For those individuals exposed to greater than the maximum suggested TWA, a bimonthly measurement would :;eetn sufficient to find a marked platelet reduction by estimation o' pla:c.lots from n smear of peripheral blood. This finding might precede symptoms. However, b'v the time the abnormality is sufficiently advanced, th ; worker may already be complaining of symptoms caused by a decreased clotcing function; therefore, 114 tHC Oo,Oo'*9a no test more frequently than quarterly Is recommended for a platelet determination. Increased . turnover of erythrocytes, probably through hemolysis, has been reported. [140,141] Counts of reticulocytes (immature, still nucleate red blood cells) give a rough estimate of the rapidity of erythrocvte turnover. Obtaining this value on a quarterly basis is suggested in workers having exposures from 1-10 ppm of benzene a.'d annually in others. Hemolysis is discovered early by laboratory estimation of the breakdown products of hemoglobin, of which bilirubin is the easiest to measure. Again, the frequency of the determination is predicat 2d upon the level of individual exposure. Normal Hematologic Values The generally accepted ranges of normal for the hematologic tests discussed in the body of this document are presented in Table XII-14 and are derived from values reported by Conn. ['..2] Ij: should be noted that these values do not represent a definition of ncrmal, but 'are only a rough guideline. Interpretation of laboratory results should be made on the basis of that laboratory's established normal i&nge for the procedure as performed there. The values listed in Table XII-14 ?re applicable only to adults. 1 L5 aOo 0 v2, ~ ?C.ic$4... . ' ..hoc _ 3^*^""""" ' T"to^ . .co^ C'4b c-,* \: -- ;* _.l____ -I.pi9 ....... ^VStar. -gAfp- - ^-24_______"_ iotl G-4'L**. 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