Document mBp71z88KRge8gBDJRnZbgon0

rORH OM.I000I REV. HI t - f J Os . ` A, INTI'H OI l'K ]: MK MO to Mac Roy Gaaque, H*D. from Richard Henderson subject Vinyl Chloride. AT Stanford 1-B AT Rw Ream l-K-5 DATE COPY TO 31, 1971 Enclosed la a copy of a brief cement free the January 26, 1971 leeoe of Chemical and Engineering News on the B. F. Ooodrioh anfioaarcona findings. I find the infcreation regarding Doe Cheaioal of Interest in view of information from other souroea on the concentration of vinyl chloride oncBier in air in their operations. The enclosed copies of oorrespondenee on the subject nay be of interest to you. V. K. Rons, who is mentioned by Dr. Stokinger In hie letter of April 6, 1970, is in charge of toxicology at Dow. Since Dow la a major prodooer of vinyl chloride, it seems that he would have poshed in 1970 for a Threshold Limit Value of $0 parts per million for vinyl chloride monomer if that had been Dow's standard since I960. RHiaph Enel. Richard Henderson OLI 1511 WHY FILE THIS COPY? IF YOU MUST (tETHIK IT, SPECIFY A DEFINITE RETENTION PERIOD- ONE Yt*E_______ __ OTHER- The Chemical World This W k "-v pr-in-ra n ite* H V* LJl fciikij L-'WsirUtt liUVs/ ins I iiu tl ' Vt>k|^V_J r .*q rsno c cbs comtjOfciuuuiaLifC^ rutii feedstock prices at "abnormally low levels." leading producer- to in crease exports of these products to more lucrative foreign markets. The SPI position lines up with that taken by fertilizer makers in Long-existing concern over possible chloride maker, urged use of a 50- their successful bid to have fertiliz health hazards to workers in firms p.p.m. exposure level in the litera er industry wage and price controls making polwinyl chloride and ture in 1961 and adopted it as a lifted to ensure adequate supplies vinyl chloride intensified dramati company standard some 15 years for the U.S. market (C&EN, Nov. cally last week with a disclosure ago. Regular physical examinations 5, 1973, page 2). The fertilizer in that indicates there may well be a for Dow workers support the safety dustry victory, however, may be in serious occupational disease prob of this level, says Dr. Etcyl H. trouble. The Cost of Living Council lem--one involving cancer. Blair, health and environmental re is considering placing some new B. F. Goodrich Co. voluntarily search director. But last summer form of price control on the indus revealed to federal and state offi Dow warned all of its U.S. vinyl try in response to what it believes cials that since 1971 three blue-col lar workers at its PYC resins plant at Louisville, Ky., have died from a workers of a "potential problem," based upon results of an Italian re search study that found tumors in to be excessive price hikes on cer tain fertilize! products. In arguing its case to CLC. SPI very rare form of liver cancer, two rats administered 30,000 p.p.m. of claims that polyethylene sells for in 1973 and one in 1971. The can vinyl chloride. up to 45 cents a pound abroad, cer-angiosarcoma--is so rare that To its credit, BFG's voluntary compared with a domestic price of federal authorities estimate that alert is the first such notice ever about 18 cents a pound, and poly deaths throughout the U.S. from made to NIOSH by a firm for a se styrene that lists for about 16 cents this cause total only 21 per year. rious health problem. But the ensu a pound in the U.S. sells in foreign Alerted to the deaths, federal ex ing probe seems likely to shake op markets for up to SO cents a pound. perts and safety inspectors rushed erators of the 36 existing PVC resin The petition also says that petro within 48 hours to the plant. Dr. plants in the U.S. as well as anoth chemical feedstocks such as ethyl Marcus M. Key, director of the Na er 14 vinyl chloride plants. ene and benzene sell on foreign tional Institute for Occupational markets for as much as four times Safety and Health, says that his their domestic price. Thus. SPI agencv will step up it- effort to deter.nn.e ,r,r. extent ct ,1,0 chsec, *c m the U.S. and in foreign countries with similar manufacturing pro Lift pries curbs on plastics, SPl urges claims, "It is not difficult to see how economic condition:, hove die tated significant sales of plastics resins and petrochemical feedstocks cesses. Citing high overseas prices luring abroad." However, two large petro NIOSH plans to develop, on a plastic resin supplies from the U.S. chemical and resin makers, Dow crash basis, criteria for stringent market, the Society of the Plastics Chemical and Union Carbide, pre work practices for use in the polyvi Industry has petitioned the Cost of viously contacted by C&EN, deny nyl chloride process. An agency Living Council to exempt petro that their exports of these products spokesman tells C&EN the criteria chemical feedstocks, plastic resins, increased significantly in 1975. might be ready in several weeks. and fabricated plastic products To add ammunition to its argu The death.- were among BFG from Phase IV price controls. ment, SPI surveyed plastics proces employees who 'worked in some The move is a result, according sors in the U.S. to assess the -.ffect phase of the PYC polymerization to SPI president Ralph L. Harding, of resin shortages on production operation, but not in drying, tin- Jr. of "raw material shortages and employment. According to the i.-hmg. or other areas. They had worked for BFG for 15 to 28years. Dr. Maurice N. -Johnson, BFG's director of environmental health, caused by the world energy' crisis and artificial domestic shortages attributable to Phase IV price regu lations." Mr. Harding says domes poll, 73 of the 159 respondent- have cut back their operations by an av erage of 23%, and 52 have laid o|f an average of 25 employees each. stresses that the causes of death are tic price limits have held resin and subject to verification and that the company L probing to see whether they are occupationally linked. Neither company officials nor Harc/ing: to end artificial shortages Water quality laws need fleshing out federal experts are certain now what the suspect carcinogen may he, if the deaths are due to job ex posure. And apparently there is no violation of the federal standard for expo-tire to vm\l chloride vapors of X "Believe it or not. indust r\ wantPublic Law 92-500 to work.'' Dr. [Monte C. Throdahl, Mon-.into s ! vice president for technoincy. !(,kl j government and industry' retire-cii- 500 p.p.m. of \inyl chloride on a tatives at a conference on nuic-irv tune-weighted-average basis. BFG and clean water, spon-ored hv Mid say- maximum exposures in its west Research In-iituie la-t wm- :n pUm- have ranged from 50 to 100 l Kansas City, Mo. As it -tain!-, he ti u in., with pos-ihlv higher expo added, the 1972 Water Quality Act sure- but not for lone periods. appears to be a skeleton, not an en D--W Chemical, a major vinyl OLI 1512 forceable system. 6 Celt N.Up ?8 1974 t Wi JW ^U-.'lV.VO X * iUibOmtOry mib-*Cl uS< wero exposed repeatedly to 100, 30 and -3 ppm oi* vinyildeno chloride vapor seven hours a day, five 'cays a waul; for a period of tip to six and one half nonths. Xenic offee to aero coon at all levels. However, at the Zj piO-ii concentration, these effects tvero considered Dlnianl and probably of no practical clcnlficanco. 3* hurenu exposed to 30 pptn of thia cubatarcc were unable to detect, the notorial. Tr.o warning properties of vinylideno chloride therefore ore not sufficient to prevent exposure iibcly to be harniui when repeated dally for prolonged ^ :* - . c. -- iVOt. *%* # Z* /.v} industrial hygiene standard of lets than p ppa is cu^- il-otcd. o v-O'.j cf the Siuaan experience within Vac Pew Chemical Ci .h/.y, uu believe thoue will be little chance of injury occur ring If c::;; ter:-on do r.ci exceed 30 ppa and if the average con- t V' !;cW |sy Str'Uih C{p.'CH, (\Zto+lvZj OLI 1513 *TT ' ; T p t * T - 50 ppm (Approximately i.30 mg/m-') ' **' ` i \- * t Vlr.yl chloride is a po.s of relatively low systemic tox icity. Torielnon, Oycn and'hove found th't repeated seven- hour exposures at ?C0 ppm caused liver pathology in rabbits (1) 1 y, \ r r> c* ".oors ho'-'ever reporv no evidence of injury at rdis level, -v ^ .UO'J j_. -1 ? -hhui increases m ivore pe vei-nht. r:t livers T-ere nonea. Other animals were unaffected by L"`; 5 On the basis of :hesc*'findings. the above seat Ivor 3 ; a erresholO limit of 50 ps:.:. fabsec'.e. 'iri'O r^v* indicates a considerable face " ^ 7 , T he 3-h U' A* , U *\ * . ' : - r " O'- v. o i. ^ . -- h. V. ' o c OU 1514 Monitoring Exposures to Vinyl Chloride Vapor; Breath Analysis and Continuous Air Sampling EDWARD D. BARETTA* RICHARD D. STEWART, M.D. * and JOHN E. MUTCHLERf Department of En; ironmental Sfedirinc, Marquette Sehoal oj Medicine, Milwaukee, Wisconsin, and Em ironmental Health Section, Biochemical Research Laboratory, The Do;c Chemical Company, Midland, Michigan An environmental survey was conducted to determine the time-weighted average exposure (TWA) of a group of chemical plant workers to vinyl chloride (VC1) vapor. This survey featured continuous multipoint air sampling and analysis using an infrared spectrophotometer. The inhalation exposure data 'sere digitized and record ed on paper tape for subsequent computer analysis and derivation of daily TWA values for each worker. A breath sampling program was conducted concurrently ith the environmental survey, and a series of breath decay curves relating post- exposure breath concentration to vapor exposure were derived from the data. To validate the breath curves derived from on-the-job data, postexposure breath curves "ere also constructed fmm breath data obtained follouing experimental human exposures to carefully controlled concentrations cf VCI vapor. The close agreement bclv.yen pOvtcxposure breath concentrations at the corresponding TW.Vs obtained bv each of tb* '"e'^eds ,li.u viinr continuous air monitoring or breath analysis is valid for estimating the vsorkcr's individual daily exposure to VCI, and provides further evidence that breath analysis is a useful industrial hygiene technique for evaluating vapor exposure. hdroduction rT,HE QUESTION* THAT MAY ARISE iollovmg an environmental survey is whether the chemical vapor concentrations measured are tnily representative of the cxr.ovi.ie being experienced by the workmen. Evaluation of the i.anges of atmosplng ie convvtitiaf.nns arid estimates of titno-v,righted "vrtaqv concentration (TWA) are all too "ftt-n based on a few spot samples obtained mulec conditions which are not rcpi c-i ntatiye of all phases of a given opetation. A nmic exact measurement of vapor exposure would have to be b.w'l on continuous moni toring of aii in tin- workman's breathing ''one during his entire woi k shift. Obviously this task js niade dilTieult and often impossible n,|. p'^.`r prrtr-n!rrl a' llic Vnieilf in J/v J'1 ' f rnftrt IHC Si, r.i; ^ M f>lr> Mj. 13*17, 1 **!'. 4 ' 1 ''f 1 w-fJ of NfuJ-vrc M,!w tuKfr, V.Vtnib n <11 j111c a1 Mit'ldr.il, Mirhitjau by the large number and variety of tasks perfoimed by today's modern chemical plant woiker. Recent improvements in automatic monitoting and data processing r-ejuioment have ptov ided a mean? for a more satisfactory so lution. Sequential samplers and automatic analyzers and recoidcrs can now be used to continuously monitor several locations or ope'.uions to piovide more valid data on which to base estimates of chemical exposure. Computers can be utilized to manage the latge volume of data gem rated by continu ous monitoring.1 Meanwhile a technique ha-- been underde velopment which more precisely defines the level of individual exposure. The realisation that the total body burden of a volatile chem ical is directly related to it? concentration in expired aii led to the development of tech niques for collecting and analyzing breath samples useful in estimating the more indi- OLI 538 Novembcr-Decnnbrr, 1969 vidualized exposure experience of each work man. Studies by Stewart el at. ~'c have shown that the excretion or "decay" of vapor in the breath can be used to characterize the ex posure. Breath decay curses constructed for several chemical solvents have proved clin ically useful as an index to chemical expo sure. These breath decay curves, for the most part, were constructed fiom postexposure breath data obtained from experimental hu man exposures to carefully controlled and relatively constant vapor concentrations. However, breath decay curves have recently been constructed from breath data collected from workers whose work enviionment was being continuously monitored/ In this study of human exposure to vinyl chloiide (YCI) vapoi, bieath decay curves constructed ftom data obtained during ex perimental exposures to the relatively uni form concentration within an exposme cham ber weit- compaicd with those detived at the theoretically equal, but biondly fluctuating, concent!ations encountered in a chemical plant atmosphere. A measure of the validitv of continuous monitoring data and the use fulness of breath analy'sis in assessinOg timeweighted average exposure was reflected bv a close similaiity between the two sets of buath decay curves. 1 WORK AREA ) STATION 3 STATION 5 . _____ Li. l! 9 1 STATION Z 1,STATION 4 |STATION ( --Ql--VJO4--1L1j------u----- J Procedures Monitoring the Plant Atmosphere The chemical installation surveyed was a closed structure housing several separate chemical processing operations. First, a job survey was conducted for each of four job classifications to determine the work areas frequented by the workmen and the time they spent in each area. For each job classification, five sampling probes were strategically placed in the work area. A sixth probe was placed outside the building, and chat coal and silica gel filters were placed in the sampling line to assure a clean air reference. The sample probes wete 5/16-inch I.D, Saran tubing through which air samples weie diaun by a vacuum pump at a rate of 17.5 liters/min to a centrally located infrared specti ophotometcr. The spectrophotometer was equipped with a 10-meter path-length gas cell sensi tive to 5 ppm of YCI at a wavelength of 10.63 microns. The YCI concenoatinn was linear ly related to absot banco up to approx imately 1000 ppm. A schematic diagram of the sampling sys tem is shown in Figure 1. Sampling was ex ecuted sequentially with a set ol six two-way solenoid valves contioiled by a timer which advanced the sampling location eve-tv 5 min utes. A visual account of transmittance was recorded on a strip chart recorder. Mean while the data weie rccoided in digital foim on paper tape by a tape punch and ehgitizcrprogiaminod to record three' equal!; spaced transmittances during the last hall of each 5-minute sampling period. The transmittance data furnished bv the spot tiopliotometei was converted to absot bance and reduced to concentration at ecu ding to Beet 's law: A, (X-X") Lo9|0(x,.-x") TIME-WEIGHTED VEAR EXPOSURE 001 Where C, 1 mtofi cs'csrirotisn of Stol-or. i P, pe' ceM of d location i wf;ng no'^-cf *ofi OCfuify Fie.em. 1. Sci'ciutir diagram of tin: infraird continuous monum-iny system. wheie A -V, A'* X, 1 = absorbance = base-line respond = response at total absorption *= response at loeatioe. i. 2, 3, 4, 5, 6 OLI 1516 iiiu I icon Industrial Hygiene Association Journal Finally, 539 < 3d it O where K = a proportionality constant. C = concentration The taped data were processed by a Bur* rueghs 5500 computer at The Dow Chemi cal Company Computation Research Labora* :or\. The computer was used to calculate il.e mean and standard deviation of concen- n.uions at each location for each 8-hour uoik shift. Finally, time-weighted average cor.centt aliens were calculated for each job cla--ific-ntion using the time-location data obtained horn the job smveys. As described el-ewheie.1 the weighted percentage of time dm ins v. iiich concentrations exceeded sev eral preehoicn lewis was also computed for u-e in c-taolbhing exposure profiles. Finite 2 describes the exposure profiles ffiequcr.cv distributions) for the four job (Lwifv.'.idcns studied during this suiwy. Tl'e=e oiOkies show the percentage of time > ,. . i j --. i__ u sliuun. They summarize several tens of thou sands of individually measured concentra tions and ieduce tlmm to single curves.' Fig ure 3 shows the corrective ttend biought .il nit bv actions undertaken to reduce the i.tmrsphei ic concent! ation of YC1 over the "-month, petiod dming which the studv was i onthu ted. Only two job classifications wari.mted extensive `tudv. but men in ail four chi'bfu e.tions weie asked to p.utieipate in the breath -ampling program. nut-T,i;Ktie x of rue Tc ce-ci-Tiutic- tutun tut mom Ficcre 2. Exposure profiles expressed as VC1 vapor concentration veisus the exposure frequency distribution for the four job classifications. cap glass v ial (Figure 4). The overall length of the pipet was about 9 inches, so it could be com cniently and inconspicuously trans ported to and from work in a lunch bucket. The plastic caps were lined with six layers of Sin an film identical to that used for the constrt.ciion of Snran air sampling bags. A 3/32-inrh hole picdrilled thtough one of the e.ijis j.'iVi. .Ci,.d ,m access far v.....drawing samples. The Saran lincts provided an ef fective gas hairier so that vapor losses were held to le-s than lOff foi a holding period of 3 days. When collecting a sample the subject was asked to it move the taps, place the pipet to his lip?, and bieathe normally in through his nose and exhale through the pipet tlnee On-tin -Job Brmth Sampling Three sepaiate breath -ampling piogrnms iw;c conducted coneurieiitly with the envir on mental plant survev, de-ignated by tl'.e lioxed portions in Figure 3. Each worker toilected thiee breath samples daily-- the first on his at rival home fiom woik, the second 5 to 10 horns later, and a final sample be fore returning to work the following day The -ample- were cole ctcd in pipets constructed fiom sl'.oit lengths of 20-mm soft glass tubing t" whhh had been welded at each end the tin ftaled poition af a 2 th atn (8-rnli <crew- Figure 3. Vi'nkly mean vapor exposure concenti.itiot.s iv.r.uiirrd tbirina the survey. Periods durme v\heh lucath -.tirpKni; ws (.ondutted are reprewmed by the bovd-in aieas. OLI 1517 540 Novcinbcr-Dcccmbcr, 1969 FicuRt 4. Glass pipct (50 ml) used for collect ing breath samples. One cap has a prcdrillcd hole for gas sampling. Both caps have Saran liners which seal the pipct chamber. times. After expelling the fourth breath he quickly caps the tube, trapping a portion of alveolar air. The importance of writing the name, date, exact lime of sampling, and the worhshift most recently completed, on the label attached to each pipet, was stressed. Aliquots weie drawn from the pipets with a 1-ml Hamilton gas-tight syringe and ana lyzed in an Acrogiaph A-600B gas chromato graph using Na cat t ier gas and a hydrogen flame detector. Separations were made with a 6-foot, j4-mch I.D. stainless-steel column packed with Carbowax 20M alkaline on Chromosotb W 60/80 mesh acid-washed. Exposure Cbainbei Operation Three experimental human cynosures to VC1 were conducted at nominal sapor con centrations of 50, 250, and 500 ppm. The exposure chamber was a room measuring 41 feet by 6 feet wide by 7.5 feet high. The room had a continuous positive air supply and exhaust system capable of maintaining a slight negative piessuie within the cham ber. Continuous distribution of the cham ber air was achieved b) recirculating tire air with a squirrel cage fan tluough a series of inlet and outlet ducts spanning the length of the chamber. The YC1 was metered into the duct canning air exhausted by the squirrel cage fait and entered the room atmosphere via the recirculation system at a rate sufficient to maintain the desired atmospheric concen tration. The sapors were introduced from a pressurized storage c\'under through 6 feet of J^-inch I.D. stainlesi-stecl tubing into a rotometer prior to entering the circulating air duct. A heating tape wrapped at omul the sLainlcs'i-stee! tubing prevented confirmation of tire VC1 and stabilized the flow of the vapor. The concentration of VC1 in the chamber was constant!)' monitored with a lYrkin-El- mer infrared spectrophotometer equipped with a 10-mcter path-length gas coll. A sam pling probe, consisting of 5/16-inch I.D. Sa ran tubing, was centrally located during the exposure to represent the breathing zone of all subjects within the chamber. The probe was moved about prior to each exposure to detect imbalance of vapor concentrations within the chamber so that necessary cor rections in the recirculating system could be made. Air samples collected periodically within the chamber throughout the exposure day were analyzed by gas chromatography for added assurance of analytical accuiacy. Both the infrared spcctiophotomrtcr and the gas chromatograph were calibrated before each experiment and at intervals throughout the exposure day. Each 7.5-hour exposure dav included a 0.5-hour lunch petiod in aji imeomaminated area outside the exposure chamber. The TWA concentration was calculated on the basis of 7.5 hours of exposure. Clinical and Labora'.oiy Proccdu>cs Each subject had been under careful medi cal surveillance by the medical department for a number of )cais, and each was given a complete medical examination a few days prior to the VCl exposuies Included wete a complete urinalysis and 2-1-hour urine for urobilinogen, complete blood count with sed imentation rate, icticulocste count, SGOT, SGPT, I.DII, alkaline phosphatase, BUN, creatinine, and bilirubin. Each subject leeched a lepeat physical examination 1 hour before entering the ex posure chamber. This examination included mcasureniVnt of temperature, blood pressure, and pulse rate, a neurological examination, and collection of blood and breath samples. A questionnaire noting the presence of any sjmptoms ol illness (tor example, headache, nausea. dr> tin oat'1 completed tire pre-ex* posiuc medical evaluation. After tire subject entered tire chamber, total expired bteatlr samples were collected every hour' by having him breathe out through a Saran tube leading to a Saiarr pla-tie col lection bag located outside tire chamber. Tidal volume and total cxpiiutoiv capacity OLI 1518 Anurhan Industrial Hygiene Association Journal 541 were measured in the morning and again late in the afternoon exposure periods. Subjective and neurological responses were measured before the subject entered the chamber. 15 minutes after entrance, and at 1-hour intervals thereafter. Flannagan Co ordination and Crawford Manual Dexterity Tests were conducted at midmorning and again in the afternoon. Breath sampling be gan immediately after the subject left the exposure chamber. A 24-hour postexposure mine sample was collected and a blood sam ple was drawn the following morning for SGPT, LDH. alkaline phosphatase, HUN, creatinine, and bilirubin determinations. Analysis of Breath Data The decay curs es for the bieath vine I chlo ride concentrations were constructed by stepwise multiple regrc'don using a digital com puter. An einphic.il lclationship of the form Cwncenttation ~ / (TWA', time) was select ed horn a choice of several terms, each based on TWA and/or time. The resulting regres sion equation best repiesents the ordered rclatiomlhp between breath vinsl chloride con tent! ation. time-weighted average exposures, and po'texposurc time. Each breath deeav rune has an associated standaid mor of icgu.-wion which can be u^cd m compute the confidence hand for any chosen lc\el of significance. The 95^e con fidence band for the m<-an of a group of obsei rations was chosen in this case to describe the staii'tical error a-sociated with tire bieath data and the regression technique. Table I Experimental Human Exposure to Vinyl Chloride Chamber Concentration - (ppm) X S.D. S9 2 261 8 493 7 491 5 Ranje (ppm) 6S- S3 289-243 318-471 525-475 TWA* (ppm) 48 248 459 491* Number of Subject* 6 4 4 7 Time*weighted Average concentration bated on 73 hemn including a 0.5*bour lunch period in an uncontuntinted area. ^Continuous exposure for 3.5 hour*. Table I shows the analyzed concentration to which the subjects were exposed. Calcu lations of the mean and standard deviation of exposure concentration are based on chart readings from the infrared spectrophotometer taken at 5-minute intervals over the two 3.5hour exposure periods. The TWA is based on the total 7.5 hours which included a 0.5hour lunch period in an uncontaminated area. The final breath decay curves intended for use as an index to YC1 exposures were ad justed to TWA cor,centi ation-, of 50, 250, P-esults L\paii'i< nlnl Ihtath Curves A total of 13 men participated in the' three i xpei in. nt.nl chamber cxgosuies at nominal concernations of 50, 250. and 500 ppm pro ducing a total of 1 GO valid bieath data points Five of the six subjects exposed to 50 ppm were re-exposcd at 500 ppm 2 days later. There was no measurable residual vinyl chloride detected on the hieaths of the sub jects prior to the second exposure. Serial bieath sampling was initiated immediately after the subjects left the exposure chamber and continued tip to 20 hours following the exposures. Fiounr 5 Breath decay curtes based cm experi mental hum.tr. exposures to all, -50. and 500 ppm of VCI (7.5-hnur TWA). 542 November-Dcccmbcr, !96'J DAILY VARIATION IN EXPOSURE TO VCL VAPOR (8 hr:TWA) 3*0 n 2K i V' VCL '< PPM " p !i t". L with confidence bands only slightly wider than those from controlled human experi ments. The close similarity between these curves and those constructed from controlled exposure data arc further illustrated in Fig ure 8. Human Responses Ficcki. 6, three shifts. Doys ef the fv'enfh '*i c*.rst rC-TD1 W.* r Variation in VC1 vapor exposure for ntul 500 ppm (Figure 5). A 100-ppm decay ctuve was interpolated from the available data using regression analysis. These curves are presented with the calculated 93^c con fidence bands foi the mean of a group of ob servations. On-the-job Bnath Ctmcs Ten workmen panicipated in the on-thejob breath sampling prog ram, producing a total of 91 usable sets ol data. Ten percent of the bieath samples collect' d wetc di-t aid ed because of pipet leakage or poor sampling techniques. Absolute breadi levels ranged f;om about 20 ppm in one .sample taken less than 1 hout after an 8-hout TWA of 250 ppm, to batch detectable levels (<0.05 ppm' in samples taken after exposures at TWAs below 50 PPmThe cxtiemeh broad vaiiation in the TW'A's experienced by woikmcn during one of the periods in which bieath sampling was being conducted is demonstrated for thiee shifts of men beating the job classification "coagulator opetator" (Figure 6). Minute, houily, and daily fluctuations in the concentiution of a t oiit.imiiiant ate iiui't d'-scriptively revealed by continuous monitoring This method of sampling quicklv points out the fallacy of judging TWA and peak exposmc concentrations on the basis of spot sampling or pet iodic sutuyi of brit t dotation. The remarkable conflation between breath concentiation and cotac-ponding TW'A val ues made it possible to construct the scries of breath decay cutvcs shown in Figure 7. From a subjective standpoint no significant untoward affects were noted at any of the exposure concentrations. The only complaints wetc those of two subjects who reported mild headache and some dryness of theit eyes and nose during the 500-ppm exposme experi ments. No odot was detected by anyone entering the exposure chamber at 50 ppm. At 250 ppm all four subjects entering the chamber initially repotted that they could detect a very slight odor of the chemical. Five of the seven subjects entering the exposme cham ber at 500 ppm weir abb' to d`"'rt We odor of YG1, but aftci 5 minutes of exposme those five were unable to detect it even with fotccd itwpit ation. Thtec of the four subjects re entering the chamber aftrt lunch wetc able Ftoi ki 7. Eu.tth dreay curv"' d.'i.rd from buouli data l. !!r. utJ from \uj.o.. !"!! m- m,thc-job rxjinsiur* to VCI v.apot Ml-liom TWA! OLI 1520 \ Aiiuiiion Industrial Uyginic Association Journal 543 to detect a faint odor of VC1. One subject could detect a faint odor on deep inspiration for approximately 15 minutes after entering die exposure chamber. The exposure had no noticeable effect on neurological responses, nor did it produce sig nificant changes in the results of mental, co ordination, or manual dexterity tests conduct ed during the exposure period. All clinical laboratoiv studies performed in the postexposure period were normal and not signifi cantly different from pre-exposure values. Discussion The object of the environmental health smvey is to identify the atmospheric contam inant, detetmine the exposure le\cl. and re late this to the hejlih ha/aid it presents. If one is to judge hnzaid by ambient conccntiation meamiemenu. then those measure ments must accmateh describe the exposure on a continuing individual basis. A carefully i'indue u d suivey combining continuous nnal\-is of th.e woik loom atmosphere with a i - nvu rbcu'ix e iob >tud\ will piovide data vault loi estunaang nine-weighted exposure. On the oilier hand, breath decay curves tinstructed ftoin bieath data collected dur ing continuous plant monitoring are in close agicement with those obtaine d from exposure ihumhei experiments with YC1, These cunes should rheicfoic be useful as a second meth od foj- as-vssing exposure to YG1 vapor. The choice of whether one or both meth ods should be used depends on presailing ciuumstanccs and on the thoiouglmcss dcm'ed. Fur example, data useful in describ ing peak exposujes nie obtained from contmumii monitoring. Concurrently, exposure iionds and concentiation giadients may help idem it y plant operational inefficiencies and eijwipment malfunctions hv rescaling specific sources of emission. Collecting these prob lems not only le.stoies a healthful work en vironment but often ic'uhs in bonus eatings b> reducing losses of taw material and jj rod net. Continuous monitoring, however, is cxtuincly t osth both in lime and in the etjuipuii m utjuired. The scope of data acquhcd is Fiovrc 8. Comparison of bieath decay curves derived from the on-thc-job data and the experi mental human expowue data. limited by the number of sampling piobes, and these probes ate not always capable of accurately measuring the individual's daily exposure experiences, especially should these involve unusual incidences such as chemical spills oi exposures outside the monitoied area, Bieath analysis has the advantage of in dividualizing each worker's integt.ited daily exposme. Bieath decay curves, ns an index of exposure, oiler a means of estimating the average daily individual cxpo'ttte on the basis of a few breath snntplcs taken serially in the postcxposurc peric'd. Consequently" breath analysis can be n.-cd to diagnose as well as cjuantitate an expowne which has already occuncd It is a relatively inexpensive and simple method which can be put into opera tion without extensive and costly p; liminary preparations. However, postexpiwm e bieath analysis docs not piovide infonnntion on the daily fluctua tions of exposme. and the peak exposure con centrations are not made evident by breath data Finally, breath analysis is not applica- OLI 1521 544 November-December, 1969 blc to all chemicals, and breath decay curves established for one chemical are not useful as an index of exposure to any other chem ical. The decay curves presented here are in tended to serve as an index of exposure to vinyl chloride vapor and are based on an exposure duration of 7.5 hours for the experi mental exposures, and 8 hours for the on-thejob study. The close agreement between the two sets of curves and the narrow confidence bands obtained in each case demonstrate the usefulness and accuracy of both methods for estimating TWA exposures and indicate the importance of breath analysis and the need for expanding its use in evaluating ex posures to other widely used volatile organic chemicals. References 1. PfcTERSON, J. f., H. R. HOVIF, E. J. SOHNf.lhFt; The Application of Computer Science to Itiriu-trial Hy giene. Amer. Imd, Hy$. Aitoe J. 27. 180*185 (March 1966). 2. Stewart, R. D- H. II. Cay, D. S. Erley, C. L, Hake, and A- W. 5cjiafmr: Human Exposure to TrturhUnn. ethylene Vapor: Relationship of Expired Air and Blond Concentrations to Exposure and Toxicitv. Arch. F.'airon, Health 2: 516-422 (May 1961). 3. SttwahTj R. D., H. H. Gay, D. S. Erley, C L. Hake, and J. . Pctuaon: Observation* on tht: Conctntrution of Trichloroethylene in lilood and Expired Air follow* int Exposure of Human*. Artier. lad. Hyg- Atsoc. J.23: 16/-17U (April 1962}* 4. Stewart, R. D.. and X*. K. Rowe- Quiiuc An* d`Etudes sur lr 1,1,1-Tiicltloroctham.'. Anh. Maladies Profess, 2H: 194-2i`l (|9C7), 5. Stewart, R, D,, H. C. Dodi, E D. Baretta, and A. W. SoitAFfEJt Huinaii Evpo<urc to Styrene Vapor. Arch, Environ. Hcohh 16' No. 5 (May 1963). 6. SifcWAfcr, R. D., E. D. Baretta, H, C Dodd, and T. R. Torkeison: Experimental Hnni.m Expo-ure to Tetiachloructliylcne. AMA Arch. Environ, Health, (In print). 7. Sttwakt, R. D., J J. C Docd, E, D. Bvfcr.m, A. \V. Schaffer, and J. E, Miii'.hllk. Chio.Hc Ovcrcxpoauic to Benzene Vapor. Prcwnied at the $*\th \mnial Meetir.c of the Society of Toxicology, Mjich 23-25, 1967, Atlanta, Georgia. Receded Ma> 26, 1963 Notices and Deadlines It is the policy of the AIHA Journal to accept and publish notices and short item- of import and interest to our icadeis subject to die limitation- of available spare. This is done as a service to our profession and no fee is charged lor such announcements. Some notices ate reccised too late to be carried to acKantage in out Jour nal. Persons supplying announcements to us should keep in mind the time schedule of our publication. The Journal appears six times per veai with the copies being mailed about the 20th of Febiuary, April, June. August, Ortobci. and December. While emergency or urgent notices can be in-cited up to tluee or four weeks befoie the mailing date, such cannot be asmied. N'oimalh the announcements should be in the Editois hands at least two months 01 more before the issue in which they should appear. Perhaps these guidelines will aid you announcement generators. OLI 1522