Document jyjewjN2M63yNVn9JpZvemVVO

The Society f the Plastics Industry, Inc. 355 Lexington Avenue New York, New York 10017 (212) 573 9400 August 20, 1980 ^RECEIVED AUG 2 5 i580 . Hi N. Wheeler* )t* TO: THE PVC HEALTH COMMITTEE Gentlemen: Attached for your information is an article from the 1980 British Journal of Industrial Medicine entitled "Lung function in workers exposed to polyvinyl chloride dust". Gloria R. Pyne, Secretary to John R. Lawrence GP: Enel. UCC 007198 British Journal of Industrial Medicine 1980;37:147-J31 Lung function in workers exposed to polyvinyl' chloride dust C P CHIVERS', C LAWRENCE-JONESf, AND G M PADDLE i From Imperial Chemical Industries Ltd, Wilmslow, CheAire SK9 IQB, UK abstract Several reported studies on the effects of polyvinyl chloride (PVC) dust in animals and man have been conflicting. The present study of the ventilatory function of 509 male workers exposed to PVC dust was made in 1977. Altogether 104 men exposed to PVC dust only, 112 men exposed to non-chlorinated solvents only, and 293 men exposed to a mixture of both completed the MRC questionnaire on respiratory function and performed simple spirometric tests (forced expiratory volume in one second and forced vital capacity). No differences were found between the three groups ' after allowance was made for age, height, and smoking. When exposure and smoking effects were considered separately, the latter was shown to be the dominant cause of reduced lung function. In this study work with PVC dust has not produced deleterious effects on ventilatory function. Polyvinyl chloride (PVC), a large tonnage raw material of fundamental importance to the plastics industry, is a white powder that was until recently considered to be inert. The basic material is formed from its monomer, the gas vinyl chloride (VCM). Although VCM and PVC have been synthesised fewover 30 years, it is only in the past 10 years that the sinister nature of VCM has become apparent. VCM has been found to produce a wide spectrum of clinical conditions, the most important being angiosarcoma of the liver in workers exposed to high concentrations of the gas in PVC production plants. This was discovered in 1974 and because a small quantity of the gas is carried forward with the PVC powder to its containers, and thus to the formulating industries the effects, if any, of the PVC powder came into question. The chance of finding effects similar to those associated with VCM is considered remote, since the concentrations are greatly reduced. The possibility of pulmonary changes being caused by inhalation of the dust however, has led to experimental and clinical research. The cytotoxicity of various polymer dusts, including PVC, to suspensions of rat alveolar and peritoneal macrophages in culture1 indicated that Now retired. tPresem tppoimmeot: Division Medics] Officer, 1CI Ltd, Millbink, London. Received 20 December 1971 Accepted M August 1979 PVC caused deaths of cells similar in amount to kaolin, magnesium trisilicate, and polyethylene. These materials produced less than 2 % fibrogenicity compared with over 10% for asbestos. On such evidence PVC had been considered inert and therefore incapable of producing lung changes. Siende et al,* however, reported radiological and clinical evidence of a moderately diffuse fibrosis in a man aged 31 who had been exposed to PVC dust for only one year. This clinical information led Frongia et aP to carry out an experimental long-term study ofthe effect on guinea pigs and rats of breathing the same PVC dust as workers in the same area of the bagging plant of a factory. In this area the PVC concentration averaged 10 000 particles/cm*, gradings being around one micron. The animals were exposed for 24 hours a day for periods between two and seven months continually. Lung histology in the two types of animals showed differing responses to the dust at the beginning of the tests, but subse quently a granulomatous reaction was reported in both species. Similar experimental studies in white rats also suggested a chronic pneumonia followed later by inflammation of the bronchial tree with mild fibrotic processes in the lung.4 This study among others prompted Vertkin and Mamontov4 to examine workers manufacturing PVC products. There were no abnormal clinical findings in the overwhelming majority of patients. Estimations of vital capacity, forced expiratory volume in one second (FEVj), and maximal voluntary ventilation s U '~Zz s ;? j : V.- 148 Chivers, Lanrence*Jones, and Paddle were performed on 64 workers. Only one vital exposure. Smoking histories were related to abnormal capacity was excessively low, 50% being at least chest radiographs, but no consistent link was found 15% better than notmal. Long-exposure employees between these and abnormal lung function. Smoking (6-12 years) were found to have FEVt/forced vital and age were both related to obstructive lung capacity (FVC) ratios less than 70% with clinical function changes and because of this it was difficult manifestations of bronchitis and emphysema. In at to isolate the specific effect of occupational vital least 50% of cases the maximum voluntary ventila capacity and exposure to PVC. tion exceeded standard values. Hydrogen chloride In view of this conflicting evidence about a gas as a possible factor in these effects was considered, material generally accepted as inert, and because of and the importance of functional changes must be the large number of people in contact with it in to judged on the results of further observations. There many industries, it was thought that a large-scale was no mention of smoking as a factor. study should be initiated to investigate lung function In 1975 Miller et at examined the lung function in workers handling PVC. of 267 workers currently employed and 87 previously employed in work exposed to both VCM and PVC. Material and methods FVC and FEVi together with mid-expiratory flow (MMF) were measured and compared with the predicted values of Morris et a/.7 Smoking habits were also recorded. Non-smokers were defined ms those who smoked less than one cigarette a day, had smoked less than 10 cigarettes a day for up to six months more than two yean ago, or had smoked only cigars and pipes. Although prevalence of impaired lung function was statistically different between smokers and non-smokers for those aged 39 and younger, smoking was not found to be a significant factor above this age. In both smokers and non-smokers when exposed to PVC dust for mctory The works used PVC for over 30 years, originally to manufacture coated fabrics, and recently also for plastic-coated wall coverings. Tbe PVC powder is mixed with several additives such as plasticisers, stabilisers, and pigments. Thus this is a user study in which there may be exposure to low concentrations of other chemicals. Whether the final product is rigid or flexible, spread on to or laminated with supporting sheet, calendered or extruded, the fundamental technology is the same. more than 20 years the FEVi/FVC ratio was reduced. Though impaired flow was more frequent with increasing duration of exposure, volume impairment was not so related. Since there were only seven non-smokers in the group, any de ductions about their performance were not thought to be justified. In 1978 Amaud et at* described pneumoconiosis in a 53-year-old man who had been exposed for 23 years to PVC in the bagging area of a vinyl chloride polymerisation plant. The histological findings from the lung biopsy specimen of moderate diffuse fibrosis and several small focal lesions were identical to those reported by Szende et aP and those produced JOBS lobs range from handling raw materials and minding machines that formulate the PVC mixes to attending to the priming process for wall coverings. A few jobs, which include manual handling of raw materials, are physically demanding for short periods but generally they are semi-sedentary. Once plasticised, the covering or formed sheet is machined in various ways. During these operations, employees are exposed to minimal amounts of dust but also to some solvent vapour. In the final stages of the process employees are exposed to do dust and to minimal amounts of solvent vapour, experimentally by Frongia et a!} Despite the radio logical changes the patient had only a slight reduction DUST EXPOSURE in his vital capacity and no reduction in gas transfer Potential exposure levels to PVC can be gauged from factor, which suggested that the fibrosis was not of the following annual tonnages: 1951, 1502; 1956, much functional significance. 2622; 1961, 3671; 1966, 6735; 1971, 12 218; and Exposure to PVC and VCM together was thought 1974, 13 957 to be important by Lilis et al * who found greater Nevertheless, although these figures give an effect on lung function when these were combined impression of the size and growth of the operation, than with either substance by itself. They studied it is considered that the present conditions with workers in three plants, all of whom had mixed fewer manual operations are much better than exposure to differing concentrations. Radiological formerly, despite the higher tonnage of PVC used. lung fibrosis and altered pulmonary function tests There is little quantitative information on which to were found in 96 workers exposed to PVC dust, the base this judgement as records of atmospheric levels changes being more pronounced in people with long of PVC dust have been kept only since 1975. L )T p v a i t t tl C r l i & l l ( t c c t i l fe j, t 1 i iJ ii i ] i t j i l Lung function in workers exposed to polyvinyl chloride dust 149 Table 1 Mean dust concentrations 1973 (mtlm*) 1976 {mg/ft!*) 1973 jtdipirmthte fferbm (mf/m*) Poetir-vntilawd mumg room 5-9 4-0 04 (0*3) Well-ventilated mnini room -- 1-5 02 (0 03) Bif ditpoul -- 0*9 02 (009) wfthotK -- 11-5(1 7) BftCkpound ten! -- 02 (002) Table 3 Exposure to dust, solvents, or both. {.Percentages in parentheses) Exposure level CMtlDKOttt Regular Occasion!) Total Soivtmt 74 <) 22 (20) 1* (14) 112 000) Duff 45 (4)) 25 (24) 54 () 104(100) f ... Moth Tenet 120 (41) 64 02) 109 07) 2*3000) m 111 15 509 In 1975,1976, and 1978 studies of the PVC mixing areas were carried out using static personal moni toring devices. Table I summarises the results while table 2 shows particle size distribution and density. Tests for VCM almost invariably showed "none detectable," but occasionally 1-3 ppm were found. PULMONARY FUNCTION STUDY Lung function tests were offered to all men working in the production areas associated with PVC and solvents. Of these 557 employees, 17 refused to take part and 31 were unavailable at the time of the tests, 23 being sick, four on holiday, three having left, and one being due for retirement. Since the population comprised the largest group in the works, leaving no comparable static non-exposed group available as controls, it was thought justified to use as controls those exposed to low levels of solvents. Therefore in the analyses the population is divided into three groups: those exposed only to PVC dust, those exposed to solvents, and those exposed to both. All the men were of the same racial origin. Table 3 shows the type of exposure of the three groups, and table 4 gives their exposure in years. PROCEDURE All the 509 volunteers were examined within one month in early summer 1977. Each rested for at least 15 minutes while he filled in a Medical Research Council (MRC) questionnaire with help from one of three trained State registered nurses. When the sub ject was completely rested, ventilatory function was measured with a calibrated Vitalograph following a standard routine. Measurement of barometric pressure and temperature were made at each session. All readings were recorded on the ATPS scale and corrected to BTPS by the calculation given by Cotes.10 Eleven subjects unable to complete the trials for psychological or physiological reasons were excused three sample readings, and estimates of the FEVi and FVC were obtained from those tracings performed. In analysing the pulmonary function data the heights, ages, and smoking habits of the individuals were taken into account. Height and age were allowed for by expressing the recorded figures as percentages of the prediction equation given by Cotes et el.11 As this equation was derived from data for healthy non-smokers, it would not be expected that the study population in which there was a majority of smokers would achieve an average of 100%. Smoking habits have been allowed for by dividing the population into three categories according to their replies to the MRC smoking questionnaire: those who had never smoked; heavy smokers who smoked, or who had only recently ceased smoking 15 or more cigarettes a day; and all others, whether smokers or ex-smokers. The three groups have been called non-smokers, heavy smokers, and others. Results The results for the three exposure groups irrespective of smoking habits are summarised in table S. As the average heights and ages of the three groups are Table 2 Particle siie distribution by percentage. (Density ofPVC particles -- I-4) Side <) >1 >3 >3 >5 >J0 S~G*'Op*feiutg comhnotu 193 33 1-9 02 003 Operating condiirtmJ 26 6 91 H 0*3 001 Table 4 Years of exposure. (Percentages in parentheses) Yeori m plant <5 5-9 1044 >15 Tata) Exposure g Solrnut Dun 43 01) 29 (26) ) (IS) 22 (20) 1)2 000) 45 (43) 2s nn 20 (19) ii do 10a 1100) Bo/M 111 (31) 2 (2!) 60 (20) 0 (14) 293 000) Total 199 139 91 73 309 X i4FaujR.'i''jj..a=!ajgaBjgi * 'CC 007201 150 Table 5 Comparison of exposure troops Dun SWttai? No* A|t: Mtaa (SO) Height (en): PUB (SD) FEV, (ml): smu FVC (ml): dma FEV, (% predicted); nxac (SD) FVC {*/* predicted); pcm (SD) Yon is plant: BHD (SD) 104 441 (U 5) 171-0 >439 4313 (7-4) 91 9 <17 2) 915 (15-0) 7-0 (6-0) 112 434(121) 174 1 343ft 4441 (64) ,, 9)4 (23-0) 91 7 (l4) 9 3 (9-6) loth 393 430(11 2) 174 3 3533 4502 (6-9) 9< 2 (19 4) 99 3(113) a s po) so similar the absence of a dust effect is illustrated both by the recorded data and by their conversion to percentages of predicted. The extent of exposure can be gauged from the data for the duration of employment in the plants. The smoking effect, irrespective ofexposure group, is clearly shown in table 6, in which, because of age differences between groups, only converted figures are shown. There is a very pronounced disparity between the results for non-smokers and heavy smokers, and the results for the others are interme diate. As this large smoking effect may conceal an exposure effect, and as there may be a synergistic effect of smoking and exposure, smoking and expo sure effects were compared (table 7). Although two of the non-smoking groups are quite small, there is no deleterious effect of dust evident in any of the smoking groups, and the smoking effect is the same in each exposure group. Finally, the effect of duration of exposure to PVC dust was considered when the effects of age, height, and smoking, typified by cumulative cigarette consumption, had been taken into account. Analysis showed that length of service had a negligible effect on the ventilatory function of those exposed to PVC dust, and supported the conclusion that their respira tory health is better than that of the controls. Chism, Lawrence-Jones, and Paddle Table 7 Comparisons ofexposure and smoking classifications Dmsl 1 Saitrmt latk No * Ait: pena SD) Hcitht (cm): sufi (SD; FEVs IV. Liwlicft); scab (SD; FVC 170 prsfioad): PCM (SD) Vttn m plan: pcm (SD) A'p-ndP Iti 34-9(11*3) 174 2 (9-1) 107 3(310 103-9 (12-) S I (4 S) If 42-5 03*1) 174-0 (51) 101-0 05*0) 101-3 (III) I I (9*4) No Aat: bus SD) Htitbi (cm): pcm (SD) FEV, lm/m predicted): oan (SD) FVC (54 pndfcud): pcm (SD) Yean to plant; mu (SD) No Aft: mu (SD) Hotbt (on): pcm (SD) FEV, W. ervdiewd): PCM (SD) FVC (!. rrtdxn-D: pcm (SD) Yean to plant: pcm (SD) 37 43-4(12!) 44 42-7 (12 7) 172 2 (W) 174-0 (4-4) 93-0 (17*7) 91-4 03-7) 9S4 (14-9) 97-1 (17-4) 7-3 (S-S) Otktr mmektn 3) 47*7 (1*4) *9 (1-0) 41 44-9 (122) 1732 (74) 174-0 (60) 99-0 07*3) 97-7 Ql-2) 96-9 (IS-6) 99-3 09 3) 7 1 (6-7) 104(11-0) 53 39 (107) 174 2 (40) ______________ 102-ft (17 5) _ _ .. 102-7 011) ,,. 1 (6 2) 132 43-3 01-4) 174 2 (4-9) 95-0 (191) 97-3 (190) 1-5 (7*3) 101 44 3 01*0) 1750 (4-ft) 1000(19-2) 100-4 0 7-9) 17 (40) Although it is difficult to draw conclusions from cross-sectional studies of lung abnormalities,11 this investigation of ventilator)' function in workers exposed to PVC dust over a prolonged period has provided no evidence of lung damage. We thank Mr S B Rawlinson, industrial hygiene officer, and Mr D J Seaborn (Central Toxicological Laboratory) for carrying out the environmental monitoring and the medical staff who assisted with this work. References Table 6 Comparison ofsmoking groups Seihtmokrrs H*ary tmoktn Othtn No Age: mttfi (SD) Heishl (cm): mean (SD) FEV, (% predicted): mean (SD) FVC KVa predicted): mean (SD) Y*n to plant.* tncas (SD) 17 40 2 (11 1) 174 5 (7-1) 103 2(11-4) 102-6 (l? 2) 7 8 (til) 215 43-3(111) 173-7 (6-9) 94 2 (204) 97-3(11-0) 14 (7 2) 207 45 2(11 2) 174 2 (ft-9) 99 2 (19 2) 99 4 (17-7) -7 (Id) 1 St> les JA, Wilson J. Comparison between in vitro toxicity of polymer and mineral dusu and their fibrofenieity. Ann Oceup Hyg 1973 ;J<S J41-J0. Szende B, Lapis K. Nernes A, Pinter A. Pneumoconiosis caused by inhalation of polyvinyl chloride dust. Medlar 1970.61:433-6. 1 Fronpii N, Spinaazola A, Bucarclli A. Experimental pulmanary lesions from prolonted inhalations of PVC dun b a crk environment Med las 1974:66:311-42. Golovaryuk AP. The effect of PVC dust in industry and experimental conditions. Vraek dtlo 1963;11:107. * Venkin Yl, Mamomov JR. On tbe state of the broncho. pultronary tsjtec in workers engaged in the manufacture of PVC products. Gig Tr ProfZabol 1970;14:29-32. I I t I i . . .`i.- ?i;. -: .im'ss -r. ' - - i- v - .1 -. J - -y;us * * - * -x. -.v-sri .V . -'h an. aj.,JH,,_! Ji KHMipCSIkJ \ ;/ i ,, 7.: . . L-*- , --.'-j -v -".J: v-'- 1 , . ucc 007202