Document dnL0aQVM7aJ44orBQjvvYX37e

Organization nesources Counselors. Inc. 1625 I Street, N.W. Washinaton, D. C. 2000G (202) 872-1090 Cable Address: ORESCON March 9, 1976 'f " if , MR 121976 3^,' -ft, 'Y- To: From: ORC Occupational Safety and Health Standards Group Vinyl Chloride Task Force i Williabh B^J&jSchols tti E The attachment was received from Nick Wheeler of Union Carbide, we though you might be interested in seeing it. WBN/cs Enclosure TRIP REPORT VISIT TO WESTERN AREA OCCUPATIONAL HEALTH LABORATORY, SALT LAKE CITY, UTAH RtCu.tU SEP 5 1975 R. N. WHEELER, JR. i datei September 4, 1975 PROJECT MO.t 510E05 file Na* 21058 URL 17216 SUMMARY Representatives from several producers or users oF vinyl chloride met with OSHA officials at the Western Area Occupational Health Labora tory at Salt Lake City, Utah, on July 8, 1975. The method for sampling and analysis for vinyl chloride by the OSHA charcoal tube procedure was discussed with representa tives from OSHA and NIOSH. The major item discussed was the procedure used by OSHA for eliminating interferences from compounds other than vinyl chloride which may be in the location sampled or from contamination during handling or storage. At present, the retention time on an SE-30 column is used for vinyl chloride identification. They have analyzed several other compounds which have been reported to be interferent with vinyl chloride or present in area sampled. None have been found with the same retention time as vinyl chloride on the SE-30 column. They have on order a Fourier Multiplex Infrared Spectrometer which they intend to eventually use as a means of verifying the presence of vinyl chloride in any questionable sample. To prevent contamination, the charcoal tubes are stored In a refrigerator reserved for these samples only; no other samples or chemicals are to be stored in this refrigerator. The only external report of analyses of the charcoal tube samples analyzed by this Laboratory is sent to the compliance officer who took the samples. It is left to his discretion as to whether or not to report the octual values obtained by the Laboratory. DISCUSSION Representatives from several vinyl chloride users met with personnel from NIOSH and OSHA at the Western Area Occupational Health Laboratory in Salt Lake City, Utah, on July 8, 1975. This visit was arranged by ORC (Organizational Resources Counselors) to discuss vinyl chloride sampling and analyses. Those attending the meeting were: John Whitney, Goodrich; G. A. (Bud) Bedford and Paul Bankovtch, Goodyear; Bert Boeneke, Allied Chemical; Steve Levitam, Diamond Shamrock; Floyd Madsen, Mike Shulsky (Chemist), and Curtis A. Foster, OSHA; and Dr. Russell Hendrick, NIOSH. BUSINESS CONFIDENTIAL -2- Project No. 510E05 The following information was sought from OSHA personnel. ). What procedure is used to analyzeJor-vtmdchloride. 2. What is being done to eIiminote<jnferencesyln the method. 3. What is the precision and accuracy of the method. Copies of the actual vinyl chloride method used by OSHA were not readily available. Mr. Madsen will mail each attendee at the meeting a copy of the method when he receives them. The chromatographic conditions employed by OSHA are listed in Table I. Samples are analyzed on a Hewlett-Packard Model 5380A gas chromatograph equipped with an automatic sampler. The entire contents of a charcoal tube sample ore placed in the 1 ml sample vial and 1 ml of CS^ pipetted into the vial. The vial is then capped, sealed and placed in the automatic sampler. Because of the problem of migration or diffusion of vinyl chloride between the primary and backup sections of carbon in the charcoal sampling tubes, the entire contents are analyzed together. Compliance officers who sample for vinyl chloride are instructed to use a second charcool tube in series with the primary tube to serve as a backup. Samples are analyzed on the gas chromatogroph using n-heptane as an internal standard. Calibration for vinyl chloride is done by injecting 50 microliters of the gas Into a volumetric flask containing 50 mis of CS_ with 0.01 percent n-heptane added. This procedure was questioned as loss of vinyl cnloride at this point would cause the analyses of charcoal tube samples to be reported erroneously high. All the industrial representatives at the meeting use a sealed system to prepare the vinyl chloride standards. OSHA personnel defended the use of the glass-stoppered volumetric, saying that when they prepared vinyl chloride in air samples in plastic bags (believed to be Milar) and sampled with charcoal tubes from the bags, they were within limits of the accuracy of the method. Desorption efficiencies are determined by injecting standard solutions of vinyl chloride in CS^ directly onto the carbon. The sampling of vinyl chloride in air from plastic bags using charcoal tubes is used as an alternate method of determining desorption eer - URL 17217 BUSINESS CONFIDENTIAL 3- Profect No. 510E05 1. If ony compounds are known to be in the area where vinyl chloride is being sampled, the retention times of the compounds are determined on the column used to analyze vinyl chloride samples. Table I lists the chromatographic conditions employed to analyze vinyl chloride. Also listed in the table are compounds with their retention times which have been tested for possible interference with the method. 2. The retention time of vinyl chloride is determined by infecting standard samples into the chromatograph each day. If the retention time of the peak from a charcoal tube sample differs by more than - 0.01 minute from the retention time of vinyl chloride, the peak is not considered to be vinyl chloride. 3. The charcoal tube samples when received by mail from the compliance officer are stored in a refrigerator which is restricted in use to charcoal tube samples only. No bulk samples or chemicals are stored in this refrigerator. Compliance officers are instructed to mail bulk samples separately from charcoal tube samples. If any charcoal tubes are received containing a bulk sample, the package is returned to the compliance officer and not analyzed. 4. A Fourier Transform Infrared Spectrometer from Digolab has been ordered for the Laboratory. When this instrument is received ond ' operating, any questionable samples will be analyzed on the Digalab instrument to confirm the presence of vinyl chloride. Precision and Accuracy OSHA personnel at this laboratory ore not responsible for developing the data for precision and accuracy determinations for the method. This is a NIOSH function and is being done at Cincinnati, Ohio. Mr. Madsen suggested that we contact Dr. Bob Hill, who s in charge of the vinyl chloride method statistical evaluation, or Ken Busch, who is the statistician at Cincinnati. We were provided with a preliminary report of the evaluation of the vinyl chloride method. A copy of this document is appended. Miscellaneous Information The only external report of analyses of charcoal tube samples from the OSHA Laboratory is sent directly to the compliance officer who took the sample. Release of the actual numerical values obtained on the samples is at the discretion of the compliance officer who receives the report. URL 17218 BUSINESS CONFIDENTIAL -4- Projecf No. 510E05 ' The personal sampling pumps used by the compliance officers are returned periodically to Cincinnati for recalibration. The compliance officer should check the flow using a flowmeter before taking each charcoal tube sample, according to Mr. Foster. Attachments: 1 Table 1 Document Manuscript Date* August 6, 1975 Date Typed: September 3, 1975 JEN:gk r \vv A , u: e. URL 17219 Project No. 510E05 TABLE I OSHA CHROMATOGRAPHIC CONDITIONS FOR ANALYSES OF VINYL CHLORIDE CHARCOAL TUBE SAMPLES Instrument Hewlett-Packard Model 5830A Gas Chromatography Column 20 ft x 1/B in stainless steel packed with 10% SE 30 on Chromasorb W Column temperature Injection port temperature Detector temperature Carrier Sample size internal standard 50C 200C 250C Nitrogen, 27 cc/min 1 pi, using H-P auto sampler 0.01% n-heptane in CS URL 17220 POSSIBLE INTERFERENCES Compound Vinyl chloride Methyl chloride Vinylidiene chloride Butadiene Ethylene oxide Acetaldehyde Retention Time, Minutes 2.18 2.05 3.63 1.13 No peak 6.03 w r JL MEMORANDUM .DEPARTMENT OF HEALTH, EDUCATION, AND WELFAR PUBLIC HEALTH SERVICE CENTFR FOR DISEASE CONTROL KATIOMAL INSTITUTE FOR OCCUPATIONAL SAFETY AND HEALTH TO t Barry J. White Associate Assistant Secretary for Regional ActiviClee-OSHA DATE; URL 17221 prom t Director* DLCD SUBJECT: Accuracy and Precision Data for P&CAM 178* Vinyl Chloride In a*i In October, 1974, OSHA requested infornatlon on the precision and accuracy of the NIOSH method for vinyl chloride. The data vas generated sometime ego, but workloads have not permitted the forniulatlon of this data Into a memo until this date. The data in dicates that the NIOSH method' Is within the accuracy and precision limits prescribed by OSHA In the vinyl chloride standard. Test atmospheres containing vinyl chloride were sampled and analyzed by P&CAM 178 to give measurements, M*, M2,.... .Mq, which were then corrected for desorption efficiency (recovery). The desorption efficiency was determined by sampling synthetic atmospheres con taining measured amounts of vinyl chloride with charcoal tubes and determining the recovery. The synthetic atmosphere was analyzed directly by gas chromatography_to give measurements, X^, ^2***'*^n' The desorption efficiency was X/Y. The relative standard deviation (RSD) reflecting the precision of method wee calculated from equation (1) which was derived after Kul. (RSD)2 - St2 . V + s*2 W" V mJI2 Cl> where S*, Sg, Sx, Sy ere standard deviations of the measurements, X, Y, Z, M Z, M,X, Y are means My are numbers of samples. II " Analysis of identical charcoal tube saaiples from synthetic Atmosphere I. X Analysis of Identical charcoal tubes samples from synthetic atmosphere II used to determine desorption efficiency. Y Analysis of replicate gas samples of synthetic atmosphere II meed to determine desorption efficiency. r 1 * < t j tI t i* I V r I ,! Page 2 -- Barry J. White X* H. B. Ru, "Statistical Concepts in Metrology" In Precision Measurement and Calibration* National Bureau of Standards* Special Publication 300 - Volume 1* 1969* p. 315-39. Synthetic air concentrations of 71.3 Mg/1 and 7.2 Mg/1 of vinyl chloride were used to prepare two sets of 29 and 27 charcoal tubes* respectively. These samples were analyzed over a 20-30 day period by various chemists* using in some cases different Instrumentation and thus* the data represent two fairly rugged sample groupings. The percent relative standard deviations of these two sets was 7.52 and 7.61 respectively. ` Additional experiments vere performed to obtain some indication of the accuracy* although accuracy was difficult to evaluate In the absence of a primary standard. These experiments generally Involved six charcoal tube samples which vere prepared from a synthetic atmos phere* analyzed and corrected for desorption efficiency. The theo retical value was the concentration which the bag was supposed to be, baaed on the measured amounts of vinyl chloride and air added. Thu6 the theoretical value was not the "true" value* since it was subject to experimental error. The value found for the charcoal tube and cor rected for desorption efficiency* was also compared to that found by direct injection of gas samples from the same synthetic atmosphere used to generate the tubes. The results of these experiments are bowh below ( 952 confidence levels reported): Synthetic Atmosphere of 64 Mg/1 (theoretical) Analysis of Gas Samples* Found * 71.2 A 0.7 Mg/1 X R.S.D. of Gas Samples 1.0Z Analysis of Charcoal Tubes* Found 69.8 1*5 Mg/1 2R.S.D of Charcoal Tubes * 2.02 Synthetic Atmosphere of 13 Mg/1 (theoretical) Analysis of Gas Samples, Found 14.5 t 0.5 Mg/1 X R.S.D. of Gas Samples 3.42 Analysis of-Charcoal Tubes* Found 13.6 i0.4 Mg/1 X R.S.D. of Charcoal Tubas 2.92 Cu r~ --rrf-oOjJ i . # } t I / ! 1 ! fi. f t I Page 3 -- Barry J. White Synthetic Atmosphere of 2.6 yg/1 (theoretical) (1 ppm) . Analysis of Caa Samples, Found 2.88 0*07 yg/1 Z R.S.D. of Gas Samples - 2.4Z * Analysis of Charcoal Tubes, Found 2.91 1 0.13 yg/1 ' Z R.S.D. of Charcoal Tubes " 4.5Z Synthetic Atmosphere of 1.3 yg/1 (theoretical) . Analysis of Charcoal Tubes, Found - 1.27 t 0.09 yg/1 Z R.S.D. of Charcoal Tubes 6.3Z . Elliott Harris, Ph.D. t i C 3D ` rPoO CO J i i t