Document RJ3g24YvqaO003a2w7vQ2kN8E

110412 CHEMICAL MANUFACTURERS ASSOCIATION December 13, 1979 To: Vinyl Chloride Research Coordinators Subject: Dr, Stafford's Letter Transmitting to NIOSH the Report Covering the Study Conducted by the Institute of Occupational Medicine (IOM) on "An Epidemiological Study of Respiratory Disease In Workers Exposed to PVC Dust" Gentlemen: In accord with advices given to him by the Legal Division of ICI Americas, and with an earlier recommendation made by the Vinyl Chloride Research Coordinators, Dr. Stafford sent a copy of the IOM report to Dr. Anthony Robbins of NIOSH. A copy of Dr. Stafford's excellent letter to Dr. Robbins is attached. His letter presents a perceptive historical perspective as well as a thorough-going recapitulation of ICI's investigative work on PVC dusts. Sincerely, JTS:das cc: Dr. John Stafford Enclosure J. T. Seawell Project Administrator Vinyl Chloride 7 \ J Formerly Manufacturing Chemists Association--Serving the Chemical Industry Since 1872. 1825 Connecticut Avenue. NW Washington. DC 20009 Telephone 202 328-4200 Telex 89617 CMAWSHI ' PO Box No 6 ' Bessemer Road Welwyn Garden City Hertfordshire AL7 1HD Telephone Welwyn Garden 23400 (STD Code 07073) Telex 264251 Dr Anthony Robbins Director NIOSH 46?6 Columbia Parkway Cincinnatti Ohio 45~6 hi Ip0i iai Chemical Industries Limited Plastics Division CC Mr John Lawrence Mr J T Seawell SPI New York City CMA Washington, DC Your ref. Our ref JS/SEW/DSO-16 Tel ext 3162 Date 6 December 1979 Dear Dr Robbins PVC DUST In 1974 when vinyl chloride monomer (VCM) was found to give rise to angiosarcoma of the liver (ASL) in humans exposed to high concentrations of the gas over long periods, various international meetings were organised to review occupational health matters in the manufacture and use of this chemical. The principal use of VCM is of course in the manufacture of polyvinyl chloride (PVC) which is normally made as a finely divided, particulate material and which is normally considered to be "physiologically inactive" with an ACGIH hygiene standard of 10 mg/mJ, the standard for the generic classification of "nuisance particulates." At these meetings and seminars, consideration was given to PVC"particulate matter but no specific risk to health was identified. Despite this finding, Imperial Chemical Industries Ltd (iCl), a large manufacturer of VCM and PVC inter alia in the UK, decided to investigate this area further by doing in vitro and in vivo work in its Central Toxicology Laboratory (CTL) and by doing full chest X-ray examinations of PVC dust exposed employees. To do the latter, ICI went to an independent body, the National Coal Boards' Radiographic Unit (NCR) which is skilled in investigating dust induced respiratory conditions. In 1975/6* the NCB examined about 450 employees and reported no unusual findings or undue level of respiratory ailments. Over the years 1975"8 however, some papers appeared in the scientific literature suggesting that there were problems caused by PVC dust exposure. Vague and ill--defined abnormalities were reported in chest X--rays of PVC dust exposed men and in some cases, allegations of pneumoconiosis were made. At the same time, the in vitro and in vivo animal work gave a similarly confused picture. At Id's CTL, the in vitro work demonstrated varying levels of cytotoxicity associated with the presence of certain types of surfactant but no notable effects were observed in animals. This lack of effect was also found in the three species animal work done under the aegis of NIOSH (Dr Trent Lewis). ICI tried to have the NCB work on our employees published but the lack of a suitable control group resulted in our abandonment of this idea. R&S 110413 o Late in 1978, ICI approached the Institute of Occupational Medicine (IOM), an independent research organisation associated with the University of Edinburgh and asked them to carry out a health and hygiene survey in ICI's oldest established PVC factory at Hillhouse in Lancashire which has been in operation for nearly 40 years. Such a survey was done in early 1979 and on 19 November, we received the IOM's report TM/79/2 dated October 1979,' a copy of which is enclosed for your attention. As you w'ill note, the IOM have observed some radiographic abnormalities and changes in ventilatory capacity of the lungs associated with PVC dust exposure. These changes are slight and there is no evidence of substantial risk to health. In our view, the IOM have made a well-disciplined study in this field and provided evidence of changes in lung function associated with PVC dust exposure. However, we remain sceptical of their X-ray findings which of course must be further discussed and evaluated by the scientific community. We are making the IOM report available to you as new information discovered in the course of what is clearly a continuing research programme. We are awaiting protocols from the IOM to decide how best to proceed in the next phase of this interesting study. The IOM presented the results of these present researches on 18 September to our Hillhouse Factory employees. The IOM report has been made available to the UK government and to the relevant labour unions- via the Trades Union Congress medical advisor. We have als.o given the information to our colleagues in the European PVC industry on 21 November and the USA to the CMA and SPI on 28 November. The report will shortly be sent also to the PVC Association in Japan. The IOM have filed the report in their Institute Library from which it may be freely obtained. The IOM are preparing a paper for publication and we hope it will be accepted by a reputable scientific journal in 1980. The report is also available in summary and complete form to employees in ICI's PVC factories. Especially in view of the three species animal research studies financed by NIOSH and directed by Dr Treat Lewis, we feel sure you will be interested to receive the enclosed report of some complementary research work which you may wish to transmit to and discuss with other relevant US Government agencies. Naturally, we would be glad to have your comments and observations on this work. If you would find it helpful to have face to face discussions, my colleagues and I would be very pleased to meet with you at any mutually convenient time and place. Should you or any of your specialists in this area be visiting the UK in the near future, we would be delighted to visit the IOM with you so that you can speak directly with the leaders of this research project. Yours sincerely Division Manager Health & Environment Protection R&S 110414 / . J ?'.~~ 1 i ' R&S 110415 rye IX 'ST - EXEL-liTTVF, uiut:r eOM UihM I U. Fur occupational health purposes, I'VC dust is classified as a "nuisance dust" and is monitored against a TLV of 10ing/mJ on an 6 hour ThA. From time to time in the literature references have appeared to research which suggested that PVC was more active than a nuisance dust both in humans and animals, Studies were therefore initiated by ICT over the past 5 years to investigate the possible effects of I'VC dust on humans and on animals. In 1975/6 ICI invited the NCB Iladiograpliic Unit to survey I'VC dust exposed workers at Ilillhousc - no respiratory disease attributable to PVC was found. Periodic checks were made with other l'VC producers in Europe and (ISA who h:ul carried out similar ehewi \--eny surveys ami again no adverse effects found. Animal test* were done .tI TCI's Central Toxicology Laboratory and no fibrosis found; some LS Government sponsored work on 5 animal species was published about the some time and reported no adverse effects. However early in 1978 a paper was published concerning a possible case of pneumoconiosis in a French factory worker who had been heavily exposed to PVC dust in past years. About this time also allegations of the occurrence of pneumoconioses in Italian I'VC workers were being made. Despite the weight of evidence that PVC dust did not cause fibrosis of the lungs in animals or man, H'l Plastics Division decided to engage the Institute of Occupational Medicine (HIM) in F.dinburgh to make a thorough investigation into the pulmonary health oT past and present employees at its Ilillhousc factory where PVC has been nude mid handled in powder form for "Jo--till years. rile IliM carried out its health and hygiene examinations on $18 employees early in and they have just completed their statistical analysis. Oral reports of their findings were given to representatives of the Houlth and Safety (executive and in Edinburgh on 1A September, to the employees concerned on 18 September and ICI management on 19 September. The H)M are writing a |>apcr on their work and will submit the paper to a professional journal for publication as soon as possible. In short, their report has given the following conclusions:- 1 ['here was no evidence of a serious progressive fora of pulmonary fibrosis except in one man out of the 618 whose disease may or may not be related to his work. This man is being investigated further. 2 Exnosure to PVC dust does have a small but measurable effect on the ventilatory rapacity of the limits. This effect is related to degree of exposure to PVC dust and to cigarette smoking habits. 5 line of the three radiologists who read the X-ray films found small radiographic abnormalities in pO of the population and these could be correlated with the observed reduction in lung function and the degree of exposure. 'i \o excess of lung cancer was found in the population studied. 5 A comprehensive survey of dust in the atmosphere found present concentrations of respirable dust to range from 0.17 to 2,86ng/ia3. In former years these concentrations were probably higher. The depth and thoroughness of this study is probably unique in the field of nuisance dusts. The study has shown that exposure to PVC dust does have an effect on man but the effect is small and difficult to detect. This is particularly true of the X--ray work where only 1 out of 5 radiologists in this study observed the abnormalities which could be correlated with reduction in lung' function. tt raav also he that *uoh naall or marginal effects are found with mnnv other nuisance dusts when they are examine,I in great dentil* fbe outcome of the study is being considered and will be discussed uirl: .mm 1 ,\ ee^, government and colleagues in the CK, European and US P\C industries over the next few months. JS/SE1./D60-lb 3 October 1070 i n s tit u t r: of o r. c u p a t i o r: a j. m e d t c i r e SUMMARY OF TI:i: RESULTS OF A SURVEY* OF THE RESPIRATORY HEALTH OF WORKERS 'll! A FASTlisY HAUUFACT'UCT;:r, POLYVTUYl Oiil.OR] i)E Eight hundred and eighteen men selected from the present and pest workforce of a factory manufacturing nolyvinylchl oride (PVC) were studied to determine whether PVC duct caused any measurable effects on the lungs of workers exposed to it. Respiratory symptoms such as cough or breathlessness, the results of breathing tests and appearances of the chest X-ray were comnared with estimates of the amount, of fine PVC dust to which each man had been exposed during his emnloymont at the factory. In studying the effects of PVC dust, allowance was made for the known effects of ageing, smoking and physique on the lungs. Shortness of breath on exertion * It was found that men who smoked cigarettes and who had also been exposed to higher amounts of PVC dust reported slight shortness of breath on exertion more often than smokers who had been exposed to lower amounts of dust. This symptom was associated more strongly with arcing and with smoking as The dust effect was not seen among non-smokers and cx-smokcrs. Breathinr tests There was a relationship between the amount of dust to which men had be on exposed at work and their ability to perform well in breathing tests: in general, the higher the exposure, the poorer the breathing test. This -."s particularly noticeable among cigarette smokers. The diagram shows that jsi cigarette smokers the effect of the average exposure is small compared to the effect of ageing, and smaller than the effect of smoking itself. But addition of the estimated effect of higher than average exposures to the results of ageing and of smoking could be sufficiently great to contribute towards chest illness in some men. Chest X-rays Even highly trained doctors often disagree on the presence or absence of spots on a chest X-ray. All X-rays in this study were read independently by three readers all of whom had been shown previously to be able reliably to detect progressive degrees of change in response to dust exposure but w For details of the study, Technical Memorandum TM/79/2 should be consulted, tt-POU S $ B i 2. differed from each other in their interpretation of what was just normal or just abnormal. One render recorded very few spots on the X-rays, regarding most X-rays ns within normal limits. One reader recorded small spots in a larger number of men and found these spots were more common in older men. The third reader recorded spots in the largest number of men and wo found that these X-rays on which he had recorded spots occurred more commonly in older men, but also in men who had been exposed to higher amounts of dust. Wo are confident from this that the more dust a man ic exposed to, the more likely he is to have small spots on his X-ray. Having said this, the number of spots on any X-ray was relatively few and all films were on the borderline between what is just normal and what is just, abnormal. Nevertheless, the breathing tests of men with spots on their X-rays were on average poorer than those of men without such spots, even when ape and height had been taken into account. Conclusions Careful selection and study of both current and past workers at the factory with measurement of current dust levels in different jobs in the production of PVC has allowed us to draw conclusions, about the effects of I'VC dust on the lungs. These effects stem from past ,dust levels which are generally believed to have been hirher than they are now, but in the absence of knowledge of what these levels were it is sensible to regard them as potentially applying to the present levels. The effects are poorer breathing tests and spots on the chest X-rays of men exposed to higher amounts of PVC dust. The effrT*r '* < ii ' o >" * i < I. j *' i ' moat m *rked m C i paw L L e -tjmokmi't, in whom there was also a relationship between dust exposure ;ir.d slight shortness of breath on exertion. These findings show that PVC is more than just a nuisance dust, having a specific, though usually slight, harmful effect on the lungs. It is accordingly recommended that efforts should be , made to reduce dust levels further and to ensure that workers are exposed to as little as is practicable. R&S 110418 9 November `1979 i Kf.TTMATKD 1.C-0G OY }' P'.TiTNG C'Al'AGTTY 07 KR l'i Yi'AhG* nV-K TO AO>.TiM. CIGARhTTP SPOKING AGO r.X! C'GPph TO FVC i/JOT APING CIGAkPATK SrOKFAG. (The fir"irrr.o in ' h i r, rii Ynri ars bared nn ndd i toral work which onr'd ftrr.''ct:; Ihnt re t'i"*!* Ind in Theca ros'iltr, arc included in a rapar wWic}, i*; V^inr: rrarTcl for a :!-! i i: n * i on . ) HR.-:ATP]NG CAPACITY IN A 35-YNAii-OI.D CIC.APKTTF SPOKEN R&S 110419 1't year.-. wan the mean time worked in the factory by the men noen XtttH, DEPARTMENT OF HEALTH. EDUCATION. AND WELFARE PUBLIC HEALTH SERVICE "Tr1**---- f--- 'iT--- CONTROL irch 17^1980 NATIONAL INSTITUTE FOR OCCUPATIONAL SAFETY ANO HEALTH ROBERT A, TAFT LABORATORIES 407S COLUMBIA PARKWAY. CINCINNATI. OHIO 4322B Mr. John Stafford, Division Manager Health and Environment Protection Plastics Division Imperial Chemical Industries Limited P. 0. Box No. 6, Bessemer Road Welwyn Garden City Hertfordshire AL7 1HD, Great Britain Dear Mr. Stafford: Dr. Robbins forwarded to me a copy of the epidemiological report on respiratory disease in workers exposed to polyvinyl chloride dust for my review and comment. I must state initially that I am not an epidemiol ogist. My role on the NIOSH conducted PVC animal inhalation study was that of an interim manager, i.e., I assumed the responsibility of p directing the study following its initiation by others. In this vain, 1` David H. Groth, M.D., Pathologist, is the prime person in NIOSH who Is jW compling the data on the PVC inhalation study and preparing the final 1/ report. 33 9P tf> The epidemiological study was well conducted and the conclusions are con sistent with the results. As stated, this is one of several studies demonstrating evidence of an association of PVC dust exposure and the development of respiratory disease. Your study and the other reports ft indicate that PVC dust exposure leads primarily to chronic obstructiveJ (7) lung disease. My personal opinion is that the effect of PVC dust exposure is mainly a nonspecific effect on the distal terminal airways. The dust is being deposited in sufficient quantity around the respiratory bronchioles of one millimeter or less in diameter, producing a marked effect on conduction past these anatomical sites to the alveoli. The result is the formation of chronic obstructive airway disease in those specific areas without the i development of a classical pneumoconotic disease syndrome. * Results from animal studies performed by members of my staff lead me to question the concept of a nuisance dust level, particularly at airborne concentrations of 10 mg/m^ total, or 5 mg/m^ respirable. Your studies, other epidemiological studies on dusts, and our own animal studies suggest that dust concentrations of 2 mg/m^ can cause a reduction in FEV^ and other physiological indicators of obstructive airway disease. Much more Mr. John Stafford - Page 2 information, is needed on the time of onset, progression of response, reversibility and other clinical interests before one can adequately evaluate the risks. I strongly concur with the statement in the Conclusions and Recommendations portion of the report, which reads " 1 . further measures to reduce individual dust exposure would be prudent." Sincerely yours ^Trent R. Lewis, Ph.D., Chief Experimental Toxicology Branch Division of Biomedical and Behavioral Science R&S 110421 u * f-v-s J IMPERIAL CHEMICAL INDUSTRIES LIMITED 4 PLASTICS DIVISION--WELWYN GARDEN CITY Dr Trent E Levis, Ph.D., Chief Experimental Toxicology Branch Division of Biomedical and Behavioral Science Department of Health, Education &. Welfare Public Health Service NIOSH Robert A Taft Laboratories 4676 Columbia Parkway Cincinnati, Ohio 45226 Fram: J STJUTORD Dirlaiwi >Wangr 4 F> Li uwirt PrstTCtim DSO-16 Ext 3162/3S59/2096 3859 - Or Stafford** Soc. 2096 - Talophoa* eontiet in TS js/sew/dso-16 3162 6 May 1980 Dear Dr Trent Levis PVC DUST Thank you for your letter of 17 March which alas reached me today - it must have come by seam&il which can take anything between 1 and 3 months! I am grateful to you for your coaments and speculations about PVC dust which I am circulating to my colleagues. As you know Dr Groth spoke about the NIOSH inhalation studies at the Bethesda symposium 20/21 March* Dr Seaton, the Director of the IOM in Edinburgh, also gave a paper on the same programme. There were of course papers from other workers in the field which tended to confirm the prudent view that more care should be given to the handling of PVC dust. We are camnitted to continue with further studies of our PVC dust exposed employees and for this work we have again engaged the IOM who, as you say, made a good job of their first investigation for us. As new results became available, we will make them available to you. I look forward to receiving Dr Groth's final report on his studies in due course. T urs sincerely i * 37 to o fct to to I j ; ! J Stafford Division Manager Health & Environment Protection Circulation Dr G Pigott Dr W G F Adams Dr B Bennett Dr F W Best Dr D P Duffield Mr G J Sleddon Dr D M Ferguson Mr M J S Gibbons Mr D Ryerson Dr T R Torkelson Mr J Lawrence Mr J Seawell Dr M N Johnson Mr P Claus Dr J G Kammuller Mr J C Thomas Dr R Mattiussi Dr J P Tassignon f. h i & it IMPERIAL CHEMICAL INDUSTRIES LIMITED PLASTICS DIVISION--WELWYN GARDEN CITY From: To: J STAFFORD Dirlaioa Haaagar BaaJLth 4 Enrtron*nt Protaatioa DSO-16 Ext 3162/3859/3096 3859 - Dr Stafford'* Sao. 2096 - Talaphona ooataot la TS Dr T B Torkelson Mr J Lawrence Mr J Seawell Dr M N Johnson I am left speechless at the time delay but at least I have acknowledgment and comment of a sort. of onset, progression of response, (interests before one can adequately oncur with the statement in the ortion of the report, which reads e individual dust exposure would be Sincerely yours, rrent R. Lewis, Fh.D., Chief Experimental Toxicology Branch Jivision of Biomedical ind Behavioral Science i J Stafford Data: 6/5/80