Document aJ62JpXkBZRQO60VELyXVOr2Y

Scand J Work Environ Utairft 1991:17:5?--9 am- Pulmonary effects of polyvinyl chloride dust exposure on compounding workers by Tze Pin Ng, FACOM,' Hock Siang Lee, MSc(OM,)2 Yong Meng Low, FRCR,J Wai Hoong Phoon, FFOM,2 Yuen Ling Ng, Dip(FCT)' .* 'l ' ' NG TP. LEE HS, LOW YM. PHOON WH. NG YL. Pulmonary effects of polyvinyl chloride dust ex posure on compounding workers. Scand J Work Environ Health 1991:17:53--9,.Spirometry, chest radi ography. environmental measurements, and a questionnaire on respiratory symptoms were used to evalu ate the effects of exposure to polyvinyl chloride (PVC) dust on 171 Chinese and Malay PVC compound ing workers in comparison with an unexposed reference group. Workers with high cumulative PVC dust exposure had a lower forced expiratory volume in I s and forced vital capacity, and a higher prevalence of radiological profusion of small opacities. Wheezing or chest tightness was also significantly more fre quent in this group. Unlike previous studies, the PVC compounding workers in this study were exposed to only negligible amounts, if any. of vinyl chloride monomer or thermal degradation products of PVC such as hydrogen chjoride. phosgene, or chlorine. The conclusion was^irawn that a low grade of pneu moconiosis and a small degrcc of lung function impairment is associated with PVC Just exposure. Re versible airways obstruction.is also likely and warrants further investigation.' r. Key terms: radiological profusion, spirometry, symptoms. In 1970,, Szende cl al.(I) first described radiological and histopathological evidence of a moderately diffuse fibrosis with granulomatous reaction in a worker ex posed to PVC dust. Since.then. several epidemiologic studies have investigated the pulmonary effects of oc cupational exposure to vinyl chloride monomer (VCM) and poivviny! chloride (PVC). These studies have shown an increased prevalence of radiological, lung function, or subjective abnormalities (2--9). It would appear, however, that, in many of the earlier studies, control of possible biases or confounding was less than adequate because of the lack of appropriate reference groups, failure to take into account the influences of age or cigarette smoking properly, or the absence of standardized procedures in radiographic reading such as the use of standard radiographs of the International Labour Office (1LO) or multiple readers blind to the exposure status of the subjects. Several studies have also provided conflicting evidence for lung function impairment (4, 6, 7). It is also difficult to be certain that the pulmonary abnormalities reported in these studies were entirely due to exposure to PVC dust alone, since combined exposures to VCM and other air contaminants were known to be present. Most previous studies have in vestigated oniv vinyl chloride polymerization workers, who were exposed to both PVC dust and VCM (2--6). 1 Department of Community, Occupational and Family Medicine, National University of Singapore. J Industrial Health Department, Ministry of Labour, Singa pore. 1 Singapore Anti-Tuberculosis Association. Reprint requests to: Dr Ng Tze Pin. Department of Com munity, Occupational and Family Medicine. National Univer sity of Singapore. Lower Kent Ridge. Singapore 0511. VCM has been reported to cause pulmonary fibrosis in animals (10), ana PVC dust exposure among work ers has been shown to induce less severe respfratory abnormalities than combined exposure to PVC and VCM (3). PVC fabrication workers have also been studied (7--9). but these included ether process workers, such as in calendering, laminating, or extruding, with poten tial exposure to thermal degradation products, sol vents, and possibly additives known to cause acute bronchial reaction. No previous investigation has studied a group of workers exposed almost exclusively to PVC dust. We have conducted a study of one such group, namely, PVC compounding workers, and present the resuits dt the radiological, lung function, and symptoms evaluation in this report. Materials and methods Manufacturing processes The study was conducted in three factories which produced PVC pellets which were then supplied to user industries for fabrication into other PVC products. The manufacturing processes were similar in all the fac tories, and no other processes were in operation ex cept in one factory, where the pellets were fabricated into PVC rails in a separate building 100 m away. The bulk of the raw material, constituting more than 90 S by weight, was PVC resin powder, which was com pounded with other chemicals such as plasticizers, stabilizers, and pigments in semiautomated processes at temperatures not exceeding 170C. The most visi bly dusty jobs in the factories were performed by 'i'Oixij;-*;. mixers, who opened bags of the dry powdered mate rials and tipped them into hoppers. Other workers with less PVC dust exposure were employed as packers/ weighers, forklift drivers, sioragemcn, machine oper ators, fillers, electricians, material testers, cleaners, and so forth (table I). Environmental assessment Current personal exposure to respirable PVC dust was measured for 10 job titles in each factory, a total of 56 personal samples of respirable PVC dust from the breathing zone of the workers was collected over sam pling periods of about 4 h at the same time of the day on cellulose ester membrane niters with a diameter of 37 mm and a pore size of 8.0 pm. Personal dust sam pling equipment (SKC Inc) was used at a flow rate of 2.0 l/min. The job-specific exposures are summarized in table .1. Table 1. Oust concentrations in the three PVC factories by job title. Job tnle Mixers Foremen Cleaner Packers Forklift ocerators Storagemen Macnme ccerators Mechanicai/eiecuicat fitters Material testing workers Screvviramng werxers Numoer of samoies. 21 3 t 9 6 3 23 .1 Mean 0v..4525 0.72 0.28 C.<5 0.30 0.47 0.44 0.20 0.33 Range (mg/mM 0.21--2.90 0.38--0.70 0.16-0.58 0.10-1.02 0.07--0.53 0.37--0.58 0.09-0.85 0.12-0.31 0.08--o.ei Frequency 80 i--------------------------------------------------------------------- , -0 -3 -6 -9 >12 -IS >18 -21 -24 >27 -30 Mg/m3 - Yr Figure 1. Distribution of cumulative dust exposure. 54 Study populations All of the eligible 171 Chinese and Malay male work ers aged 21 years and above and currently employed in production and maintenance work in these factories were studied. Since almost all of the workers were ex posed to some degree of PVC dust, an external com parison group of unexposed workers was also studied at the same time. These were Chinese and Malay male workers, aged 21 years and above, with equivalent job titles such as drivers, mechanical workshop workers, electricians, and plumbers in three granite quarries (27 workers, 100 response) and in one hospital (21 workers, S7 response). The comparison workers in the quarries were exposed to low levels of silica (aver age 0.15 mg/m3 respirable granite dust). A structured questionnaire was administered by trained field investigators to each worker, who pro vided his personal data, a detailed work history, (in cluding previous employment in other dusty occupa tions), information on previous medical history of. tuberculosis, hypertensive heart diseases and so forth, smoking- habits, and responses to the British Medical Research Council questionnaire on chronic bronchitis,as well as to additional questions on wheezing or chest tightness and atopy. Spirometric testing was performed on a dry-yedged bellows spirometer (Vitalograph2), which was regu larly calibrated before use, on Monday mornings when workers began their shifts after a weekend off. Each subject performed maximal forced expiratory maneu vers in the standing position without a nose clip, and the best of three acceptable curves was used in deriving ihe forced vital capacity (FVC), forced expiratory vol ume in 1 s (FEVI 0), and the FEV "'o [(lOOxFEV, 0)/ FVC]. All of the values were corrected to body tem perature and pressure saturation (BTPS). Height (to the nearest centimeter) and weight (to the nearest gram) was measured, the subject being without shoes and in ljght summer clothing. Chest radiography was performed on the entire group of mixers (who were the most highly exposed to PVC dust) and subsamples of exposed nonmixers and unexposed referents. Since the mixers were a gener ally older group, the exposed nonmixers included other production and maintenance workers except those in the PVC railing and screw departments, who were mostly young workers. The external comparison group included only workers in the quarry, who were also comparable in age to the mixers. Postero-anterior radi ographs of the chest were taken on high-quality largesized film and were then read independently and in ran dom order by three readers, who were not aware of the exposure status of the subjects to which the radio graphs belonged. The profusion of rounded and irregular small opacities was read, with reference to standard films, and according to the ILO International Standard Classification of Radiographs of Pneumoconiosis of 1980. There was reasonably good reading agreement between the observers (appendix). JO CS'T C/] CD o <N) Analyses Radiological opacities were defined categorically as Since the observed respiratory effects were almost cer tainly the results of cumulative PVC dust exposure, which is a function of exposure intensity and duration, a cumulative dust exposure index was estimated for each PV'C-exposed worker on the basis of information provided on the duration of employment for every job ever held in the factories. The current factory- and jobspecific dust concentration was assigned to each job held and multiplied by the duration in years and cal culated as follows: C = K,-T,. a profusion of small opacities of 0/1 or greater, 1/0 or greater, or 1/1 or greater, as read by two or more of the three readers. Separate analyses of the preva lence of radiological opacities for each reader were also performed. Stratified analyses and the Cochran-Mantcl-Haenszel test were used when the prevalences of radiological opacities were compared, and also when the prevalences of symptoms were compared by ex posure groups with control for the influence of aee (<45 years. >45 years) and smoking status (nonsmoker and ever smoker). Thirteen workers with significant dust exposure from where C = the cumulative exposure index. K = the mean dust concentration (mg/mJ), T = exposure duration (years), and j = job category. It was recognized, how ever, that current measurements could not be assumed other previous occupations, one worker with previous pulmonary tuberculosis, one worker with hypertensive heart disease, and one worker with current respiratory tract infection were excluded from the analysis. to reflect the previous dust exposure intensities ac curately. Hence, the cumulative indices were only used to categorize workers into high and low cumulative exr Results posure groups. This classification was done with the ' use of an arbitrary level of 10 mg/m3-years to sepa Table 2 shows the mean age, height, and the propor rate those with high cumulative exposure from those tions of each ethnic group and smokers by exposure with low (or average) exposure. Typically, those with group and table 3 the exposure characteristics of the a cumulative index higher than 10 mg/m-'-years would groups. Multiple regression modeling showed both the represent a mixer exposed to an average PVC dust FEVI 0 and FVC to be significantly related', in ex concentration of 1.0 mg/m3 for 10 or more years. pected fashions, to age (P< 0.001), height (P< 0.0001), The inclusion of, say, a packer typically exposed to and cigarette-years (P<0.01). Race was not a signifi 0.33 mg/m3 for 30 or more years was also allowed cant independent variable after adjustment for smok for. The distribution of the cumulative PVC dust ex ing in the model. FEV. ,, and FVC, after adjustment posure indices is shown in figure 1. The unexposed for the effects of these influencing variables, were both group was assigned a nil cumulative exposure to PVC lower in the PVC-exposed groups (table 4). The per dust. centage of predicted FEV, 0 and FVC in the unex Comparisons of the lung function parameters be posed group indicates that their lung volumes were tween the exposed groups were performed by multi 1 comparable to the external population norms, where ple regression techniques using general linear regres as both FEV, 0 and FVC were about 4 lower in the sion modeling procedures from the SAS (statistical low-exposure group and 7 lower in the high-expo- analysis system) programs. The FEV. 0, FVC, and sure group. FEV To were adjusted for age, height, cigarette-years, ' The prevalence of respiratory symptoms among the and race, entered as covariates in the models. The lung exposure groups, after control for age and smoking, function parameters of the exposed groups were com did not show any statistically significant differences pared with those of the unexposed group with sig except for frequencies of wheezing or chest tightness, nificance testing by an analysis of covariance. In ad which was greatest in the high-exposure group (table dition, the lung function parameters of all the groups 5). Radiological smail opacities, as read by at least two were compared with external population norms with readers, with profusion 0/1 and greater, age and smok the use of prediction equations for Singapore Chinese ing being controlled for, were significantly more fre and Malay males (11, 12). quent in the exposed groups in comparison with the Table 2. Physical and smoking characteristics of the suojects by cumulative exposure group. Grouo Unexposed (N = 48) Low exposure <N = 121)* High exposure <N = 34) * < 10 mgrm'-years. * i 10 mg/m*-yars. Age years Mean SO Heignt <cm Mean SD 36.0 35.2 41.9 12.7 10.1 8.77 167.1 167.1 165.4 5.6 6.2 5.3 Race Chinese N / 29 61 102 64 24 71 Malay N 4/ 9 19 19 16 10 29 Nonsmoker N v, 16 33 63 52 10 29 Smoktng Ex smoker Current smoker N% N% 48 65 9 26 28 56 52 43 15 44 Cigaretteyears Mean SO 229 377 105 162 217 404 evt 01 55 oo Q Table 3. Exposure characteristics of the subjects by cumulative exposure group. <PVC = polyvinyl cnlonae) Group LJnexposeo Low exposure (< 10 mg/m'-years) Hign exposure (a 10 mg/m'-years) PVC cumulative exposure Mean _ 2.9 18.0 SO 2.6 5.5 Years exposed 10 PVC Mean _ 7.5 14.7 SO 6.2 -4.2 Mixers N% Job Exposed nonmixers N V. 9 74 30 68.2 92.6 4 11.8 Table 4. Lung (unctions by exposure group. |FEV10 = forced expiratory volume in 1 s, FVC = forced vital capacity, FEW* = (100 rEV.^FVCl Group FEV, o <!)Mean SO FVC il)* Mean SO FEV, 0 FVC (V. of predicted)0 (*/ ot predicted)0 Mean SO Mean SO FEV/.0 Mean SO Unexposeb Low exposure (< 10 mglim'-years) .Higtvexposure (a 10 mg/m'-years) 3.13 0.41 3.03 0.44 2.93 0.41 3.64 0.48 99.3 12.2 99.4 11.8 86.3 6.2 3.47 0.53 96.4 123 95.1 11.9 87.4 6.2 3.39 0.47' * . 92.7 12.4-- 92.3 12.0** .86.5 6.3 * Adjusted for age, height, race, cigarette-years. B Adjusted for cigarette-years. P<0.05. ** P<0.01 (analysis of covariance). Table 5. Respiratory symptom prevalence by exposure group. Symptom Unexposea N Vs Low exposure (< 10 mg/m,-years) H V. 4 High exposure (is 10 mg/m^years) N V. Cougn Mornmo Day or nipnt Three mentns in year Phlegm Morning Day or ment Three months in year Fenoos cl cougn and cnlegm Breathlessness Wheezing/chest tightness 5 10.2 8 16.3 3 6.1 8 16.3 ' 9 18.4 8 16.3 3 6.1 10 20.8 x 2 4.1 11 9.1 7 5.8 6 5.0 22 18.2 13 10.7 14 11.6 1 0.8 22 18.2 10 8.3 6 17.6 5 14,7 4 11.8 8 23.5 6 17.6 6 17.6 - 0.0 6 17.6 8 23.5 ' P<0.01 (Cochran-Mantel-Haensjel test o( general associalicn conirolling for age ana cigarette smoking). unexposed group (table 6). Stratified analyses showed that age, but not smoking, was significantly associat ed with radiological small opacities with profusion >0/1 (at least two readers). Altogether 17 persons had small opacities of pro fusion 1/0 and greater in their radiographs, as read by at least two readers. Four persons had radiological profusion 1/1, and one had 1/2 profusion. No one in the uncxposcd group had radiological profusion greater than 1/0. There was a twofold higher preva lence of radiological opacities of profusion 1/0 or greater in the high-exposure group as compared with the low-exposure group. Radiological small opacities of profusion 1/1 and greater were seen only in the high- exposure group. Similar results were obtained when the radiographic readings for each reader were used in the analyses. The predominant types of opacities were irregular although the readers differed in their interpretation, particularly with respect to the shape but not the size of the opaci ties (which were all read as <0.5 mm in diameter). Reader one read mostly irregular opacities, reader two read more irregular than rounded opacities, and reader three read more rounded than irregular opacities (ta ble 7). Discussion In a cross-sectional study, the reference group is the most appropriately chosen from within the same fac- Table 6. Prevalence o! radiological opacities cy reader ana exposure group. Paramelers Reader 1 Profusion 5:0/1 Profusion > 1/0 Profusion in Reader 2 Profusion 5:0/1 Profusion 2 I/O Profusion a 1/0 Reader 3 Profusion 0/1 Profusion a 1/0 Profusion 21/1 Two or more readers Profusion 2 0/1 Profusion 2 1/0 Profusion 21/1 Unexooseo* (N = 27) N% 7 25.9 1 3.7 1 3.7 4 14.8 -- 0.0 -- 0.0 4 14.6 -- 0.0 0.0 _4 14.8 0.0 -- 0.0 Low exoosure5 (M = an N V" *9 60.5 *.3 '<6.0 -- 0.0 33 46.9 12 14.8 -- 0.0 32 39.5 14 17.3 8 9.9 37 45.7 10 12.3 -- 0.0 Hign exposure4 <N s29) N V 21 3 27 6* 4 13.8* 16 55.2* 8 27 6* 4 13.8** 13 44.8* 7 24,1* 6 20.1 16 55.2* 7 24.1* 5 17.2" *. Mean age of the group 41.1 (SO 12.4) years with seven (26 V.) nonsmokers, three (11 V.) ex-smokers, and 17 (63 V.) current' smokers.' e' Low exposure = <10 mg/m'-years; mean age of the group 35.2 (SD 10.3) years with 60 <50 */) nonsmokers, seven (6 Vi) ex smokers, and 53 (44 V.) current smokers. c High exposure = a: 10 mg/m*years; mean age o1 the group 41.0 (SD 9.1) years with nine (26 V) nonsmokers, nine (26 V.) ex smokers, and 16 (47 V.) curreni smokers. Pus0.05, ' P<0.01 (Cochran-Mantel-Haenszei lest of general association, controlling lor age anc smoking status). Table 7. Distribution ot radiological types by reader and exposure group. Unexoosea Roundea Irregular Low exposure (< 10 mg/m'-years! Rounoed Irreguiar Reader 1 Profusion 2O/I Profusion 2 1/0 Profusion 21/1 Reader Profusion 20(1 Profusion 21/0 Profusion 21/1 Reader 3 Profusion 2O/I Profusion 21/0 Profusion 2 1/1 34 --1 --1 -- 49 -- 13 ---- -> 1 * 11 27 ---- 48 ---- ---- 1 ---- -- 24 ' 10 5 8 4 3 High exposure (210 mg/m' years) nounoeO Irregular -- 21 --8 --4 88 53 31 94 52 42 tory if it is certain that it is indeed unexposcd, Our en vironmental assessment clearly indicated a secondary exposure in the ambient air for almost all of the work ers in these factories; and this secondary exposure was likely in itself to produce some degree of pulmonary effects. It was therefore necessary to choose an exter nal comparison group, which we believed was ap propriate for the study since it was an occupational counterpart in other industrial undertakings. The va lidity of this group was well supported externally by the good approximation of their lung functions to predicted norms from other independent population samples. The previous dust levels in the factories were not known, but there were reasons to suppose that they were probably higher than current levels. Since only current dust levels were known, it should be empha sized that the estimates of cumulative PVC dust ex posure were not based on actual dust exposure levels. The data in this study were, therefore, used only for categorizing broad groups of PVC-exposed subjects and not for deriving quantitative exposure-response relationships. Exogenous sources of VCM and thermal decompo sition products may be ruled out as the cause of the observed pulmonary effects since VCM exposure from residues in the PVC powder was negligible and irri tant and toxic gases like hydrochloric acid, VCM, phosgene, and chlorine are only formed at temperatures in excess of 225C. We also made measurements 57 ^ C/l vi o o Cl at ihe mixer and extruder, and hydrochloric acid and VCM were not detectable. However, it is more diffi cult to exclude the possibility that the radiological opacities could also have resulted from additives con taining radio-dense calcium and barium compounds in the mixture, although only smail quantities of these substances were used. The radiological readings were all done by physicians experienced in the assessment of radiographs for pneu moconiosis, and standard guidelines were used under controlled condirions so as to eliminate subjective bias and produce unequivocal case identification. Under the circumstances, the effects of aging and cigarette smok ing were unlikely to produce radiological opacities more profuse than category 1/0. There should there fore be little if any doubt that at least radiological pro fusion 1/1 in five workers indeed represented PVC pneumoconiosis. Both diffuse micronodular and linear-reticular opacities have been described in case reports of PVC pneumoconiosis, characterized histopa.thologieallv as pulmonary fibrosis associated with granulomatous lesions (1. 13). Similar histological changes were ob served in experimental studies with guinea pigs and rats (14. 15). As in previous epidemiologic studies (3. 5. 7), the present study indicated that the radiological lesions arising from PVC dust exposure were of limit ed profusions with a predominance of irregular small opacities. The reported prevalence of radiological le sions varied greatly among the studies. It is. however, difficult to make vaiid comparisons among the studies because of differences in procedures and criteria for radiological case definition, although in two of the studies, 1LO standard fiims and radiological classifi cation were employed for reading by a minimum of two or three readers (5, 7). Furthermore, the preva lence of radiological small opacities may be expected to vary with the level of PVC dust exposure, but such measurements were only performed in one study (6). In the study by Soutar et ai (6), the estimated dust in dex of 14 mg/m-'-years appeared to be comparable to that of the high-exposure group in our study, but in both studies, past levels of PVC dust exposure was un known. Previous reports of an association between PVC ex posure and a restrictive type of lung function impair ment (2, 3, 6) was supported by the findings of the present study. The average lung function loss was modest, but, given individual variation in responses to PVC exposure, a few persons in any exposed popu lation may be expected to experience clinically signifi cant lung function impairment. PVC exposure was also found to be associated with an increased prevalence of dyspnea in the study by Soutar et al (6). No such association was demonstrated in our study, but it should be noted that, whereas the study by Soutar et al included past workers, we could only study current workers who might probably be overrepresented by those whose functional impairment was not severe enough to prevent them from continuing with their rent employment. We did. however, find an incre: prevalence of wheezing or chest tightness, and < findings have not been reported in previous stuc Apparently, responses to these symptoms were neiicited :;t previous studies. The possibility of rr ble airway obstruction, however, corroborates wur resuits of a recent study showing across-shift FE changes in PVC fabrication workers (9). and a re report of bronchial asthma from inhalational pr. cation tests with PVC dust (16), and should there be further investigated. Acknowledgments This study was conducted with research RP88037I from the National University of Singa and the support and assistance of the Singapore. Tuberculosis Association. We also wish to than Moozoomdar for his interest and special assist: and the Permanent Secretary of the Ministry of La for permission to publish this report. References !. Szende B. Lapis K. Ncnes A. Pinter'A. Pr.eurr.o. sis caused bv the inhaiation of polyvinyl chloric; Med Lav 1970:61:433--6 2. Miller A. Teirstein AS. Cituanc M. Seiiko:: I. Cl in pulmonary function in workers exposed :a sir.-, ride and polwinyl chloride. Ann NY Acad sc: 246:42-52. ' 3. Liilis R. Anderson H, Miller A. Selikoff I. Puirr changes among vinvi chloride polymerization Chest 1976:2:299--305. 4. Gamble J. Liu S, McMichaet AJ, Waxweiler R. : of occupational and r.on-occupational factors respirators- svstem of vinvi chloride and other w, J Occup Med 1975; 18:659--70. 5. Mastrangeilo CT. Mar.no M. Marcer G. et al. Pc chloride pneumoconiosis: epidemiological stuc:posed workers. J Occup Med 1979:21:540--2. 6. Soutar CA. Copland LA. Thornlev PE. et al. E: oiogical study of respiratory disease in workers e :o polyvinylchloride dust. Thorax 1983:35:644 7. Olivers CR. Lawrcncc-Jones C. Paddle GM. L-cr lion in workers exposed to poiyvinvl chloride c J Ind Med 197S:37:147--51. S. Baser St. Tockman MS, Kennedy TP. Pulrr.or.a: tion and respiratory symptoms in poiy'tr.v:. fabrication workers. Am Rev Respir Dis 195: 203-8. 9. Ernst P. De Guire L. Armstrong B. Theriault structive and restrictive ventilatory impaitrr.en: vinvlchloride fabrication w-orkers. Am J Ir.c Mr 14:273--9. 10. Prodan L, Suciu I. Pislaru V, Ilea E, Pascu perimenia! chronic poisoning with vinyl chlor.de chloroethene). Ann NY Acad Sci 1975:246:1: ! I. Da Costa JL. Goh BK. Prediction normograms function measurements in adult Chinese. SincapJ 1971 :12.4:193--8. 12. Zee KO. Ventilatory function in normal indur.r: ers in Singapore. Ann Acad Med Smidrc.: (>uppil:5S7--95. 13. Arnaud A. Pommicr de Sami P. Carte L. P " wl Cbarpin 1. Polyvinyl chloride pneumoconiosis. Thorax 1978:33:19--25. 14. Frongia N. Spinazzola A. Bucarelli A. Experimental pul monary lesions from prolonged inhalations of PVC dust in a work environment. Med Lav 1974;65:321--42. 15. Agarwal DK, Kaw JL. Srivastava SP. Seth PK. Some biochemical and liisiopathological changes induced by polyvinylchloride dust in rat lung. Environ Res 197816:333-41. 16. Lee HS. Yap J, Wang YT. Lee CS. Tan KT. Poh SC Occupational asthma due to unheated polyvinylchloride resin dust. Br J Ind Med 1989;46:820-2. Appendix Agreement between the readers of the radiographs Reader 2 Reader 1 Reader 3 01-- 0/0 0/1 1/0 1/1 1/2 Reacer 2 01-- 0/0 0/1 1/0 1/1 1/2 0/-- - 8 - - 0/-- 0/0 48 21 2 0/0 0/1 -T 4 24 9 1 -- 0/1 1/0 -- -- 10 1 -- 1/0 _1/1 . -- -- 1 2 -- 1/1 1/2 ----_ _ 1 V2 8 63' 14 -3 -- 7 18 2 -- -- -- 1 4 2-- -- -- 2 8 3-- -- ------" 1 Kendall's lau-8 0.637 (SE 0.041) Kendall's tau-B 0.632 (SE 0.054| Reader 3 Reader 1 01-- 010 on 1/0 1/1 1/2 01-- 0/0 -- 55 30 3-- -- 0/1 -- 5 17 5 1-- 1/0 -- -- 5 2 0 -- 1/1 -- -- 3 7 3 -- 1/2 -- ------ -- 1 Kendall's tau-B 0.574 (SE O.C5<) Rr eceived for publication: 9 Mav 1990 C-.'l c,n 59 o p ((( HYDRO Itififitf POLYMERS Vinyls Division Mr R T Gottesman Executive Director The Vinyl Institute Wayne Interch. Plaza II 155 Route 46 West Wayne, NJ 07470 USA Our ref. HMC/PAM Your letter of Date 16 April 1991 Dear Roy, PVC DUST I draw your attention to the attached paper, together with the handwritten note from our own Medical Advisor. t jiYou will be advised of the results of a critique of he paper. Yours sincerely; " H H Clayton Senior Environmental Advisor ((( HYDRO POLYMERS Vinyls Division Hydro Polymers Lid. Newton Aycliffe, Co. Durham, DL5 6EA, England. Telephone: National: (0325) 300555. Internal: (44 325) 300555. Fax: (0325) 300215. Telex: 58322 Internal Memorandum PFrom | Dale 9/ ^rfrj L,. /mltd' /ImK `fu.7 cm. yen, nu/&. f *ii3i H iJU CJm* /turfwyiot'' PVC GAcosJd - (/fVWr fb CrHvmJkt, &n<i- -wdL Aty Lh&u) ' ' v/----- news Release _630 I 12 November 1990 ? POS9IELS LINKS BETWEEN INDUSTRIAL POL LOT ION. AND ILL-HEALTH IN THE cjpNLMUNITY TO 5E INVESTIGATED j David Trippier, yinister of State for the Environment and Country'sids, has today arfnounced a series of studies to investigara possible links* between pollution from industrial installations and ill-health in the local ccnmunity. The Department of the E.nvironmJnr has ccMisslonel the Snail Area Health Statistics Unit (SAHS^I) to carry out these studies. % SAHSU is an indapon.cMnt body, which. is jointly funded by several Government Departmer| ts. It has uuilt no a nacionwida, ( ccmprchenai ve data base on the distribution of mortality (by \ specified cause) and on the 'incidence of cancer related to small areas cf the country. This Enables it to examine quickly reports of unusual clusters of difcease (particularly cancer) in the neighbourhood of industrial installations, and give advice as to whether the health statistics indicate the need for further in depth ir.v-stigat<on of the iffatter. It could then be referred to the appropriate ~pert Advisory Committee for definite advice. A study is already c&idervay into an alleged increase in ?0 C/l r* a *ovi the Incidence cf cancer c*f larynx m people living in the a vicinity of a small ir.cincida tor for waste oils end solvents at Charnock Richard, Lancashire. SAKSU has concluded that it is -i- unlikely chat the slight incjeasa In the ratio of obaervfld to expected coses is associated' with Che incinerator. ^ However, as a further check the study h'es buun extended to jlncluda oth.Ar incinerators of a similar Cy>&. 9 In addition to the' Initial study tha SAHSU Steering Committee has now agreed a more long term programme!, suggested by *I DCS, which will investigate the incidence of mortality and cancir in the neighbourhood of: - benzene works - municipal waste incinerators vinyl chloride workfe j. coke works and smokeless fuel plcnts Welcoming the studies, Mr Trippiec aald: "These industrial operations nave .been choc^n because they are time to time thfe subject of public edneern about pollution and because of thi potential cfv the chc;r icals involved to cause harm. The information obtained will assist the Department in assessing the effectiveness of current controls end to develop policy in future." i Thi3 work will be' carried out alongside the rapid investigations that SAH$U wuuld normally undertake' The results of the studies will be published in dbe course. NOTES TO EDITORS C-d 'r* cn am H4 SAHSU was established at the London School of Hygiene ahd Tropical Medicine in 1987 following the report of tha Independent Advisory Oroup chaired by Sir Douglas Black arid set up to ir.vostlccta the possible increased incidence of'cancer in West 2- - T II Confer ia One the reccpmer.dat lens was the encouragement should be given co an organisation buch as OPCS or MPC co CC- ordinate centrally the monitoring of small area health statistics arcur.d major ins cal 1 at lend producing dischargee that might present a carcinogenic or mutagenic hazard co the public. In this way early warning of any untoward health Effect could be obtained". SAKSU is funded Jointly by the Department of Health, che Department of the Environment. the Health and Safety Executive and the Scottish, Veiuh and northern Ireland Offices. The terms of reference ace: iuual - co examine quicKiy reports of unuuual clusters of disease particularly in the neighbourhood of industrial installations and 4dvi.bC- authoritatively; as soon aa possible; ' i I - In collaboration with other scientific groups, to build up reliable background information on the 4iatribution of disease amongst small areas so that specific clusters con be placed in proper oontext; ! - to 3tudy the available statistics In order to detect any unusual incidence of disease as early ad possible and where appropriate, to investigate; 1 - to develop the methodology for analysing and interpret ing statistics relating to small' areas. J Frees Enquiries: (Out of Hourl: Public Enquiries; -3r- J071 276 09: 071 276 4120) 071 276 0900 v4