Document YGMjE6rzdK78z8MQbrGpn81v8

Tataohm 01-738 3001-t ooied bv MCA. 4/3/74 BRITISH CHEMICAL INDUSTRY SAFETY COUNCIL OP THl CHEMICAL INDUSTRIES ASSOCIATION Chairman: E-J. CHALLIS Sacmry: iS.V-.BEAB ALEHB1C HOUSE. S3 ALSEH.T EMIAHKHEMT, LQNOON SET 7TU COM yiD-UflTIAIi To: Heathers of the Medical Cmmittnc: 3CISC and MCA BCXSC Cir. 7k CIA/T100/2/Md. : 5th' March, 197k Hear Sir, RZPQRT 0W VCTIL CHLORIDE - M0B0ME5 ' . I *m new enclosing a copy of Dr. Whitehead's report . on The Toxicity of Vinyl Chloride Monomer. [VCM) mentioned under Any Other Kisiness -.(para.l)cf the Minutes of the Medical Committee meeting held on Tuesday, 5th February, 197k. Tours faithfully. " ' - i u'Xc'-/^y IT. W. Bean, Secretary.. ' Enc. BCISC Doc. 8/Tk ASV 0000919 ,CIiX DOC. S/TJi THE TOXICITY OF VINYL CHLORIDE MONOMER (VCM) The VCM story started la I9f6 when Lefevre of Solvay In Belgium described a condition which has since become known as*Aero-osteolysis', which had occurred In men cleaning out autoclaves used In the polymerisation of VCM In the manufacture of polyvinylchloride. ' Very briefly, the process takes place In three stages. (a) Vinyl Chloride Monomer Is made by the chlorination of ethylene to form ethylene dichloride and this Is then cracked to give Vinyl Chloride Monomer and Hydrochloric Acid. (b) The Vinyl Chloride Monomer, which is a gas, then passes into a large autoclave where it is reacted under pressure with water, ft plasticiser and a catalyst to form a slurry of polyvinylchloride (PVC), <c) This PVC slurry then passes to a drying plant and is then further processed to a powder. In the first stage of the process, l e the manufacture of the monomer, the background levels of VCM in the atmosphere are of the order of ten parts per million. On the autoclave floor the levels of VCM in the atmosphere are In.the range of SO to 100 parts per million. During the polymerisation, PVC powder tends to stick to the aide of the autoclave and it is necessary therefore that they should be cleaned,and until recent years this had to be done by hand and men going into the autoclaves with scrapers after the autoclave had been evacuated and purged of any gases. There are difficulties in getting rid of all the gas before opening the manhole at the top of the autoclave with the result that a puff of un reacted Vinyl Chloride Monomer, albeit it momentarily, is given off to plant atmosphere and the concentration of VCM at this particular point of time Is of the order of oncthousand parts per million. It should he noted therefore that It is at this stage of the operation that the highest exposure to VCM is experienced and it is also possible that In the process of scraping off the PVC powder from the side of the autoclav- further exposure also occurs to pockets of VCM trapped behind the powder. Since Lefevre published his account of Aero-osteolysis many other cases have occurred throughout the world and 1 believe 1 am correct in saying that almost without exception the condition has only affected autoclave men. The main features of 'Aero-osteolysis* are bony changes which typically involve the terminal phalanges of the fingers, but changes in ocher parts of the skeleton, such as the sacro-Iliac joints, the patella and the toes have been noted. These bony changes are often preceded by Raynaud'* phenomenon and are associated with scleroderma. It Is apparent therefore that Acro-oteo!ysls is a systemic disease. RSV 0000320 :2 : In ICI there have been four cases - two of Raynaud's phenomenon only and the other two with InvoLvement of bone. Since the occurrence of these cases conditions have been greatly improved In that many of the autoclaves are now cleaned mechanically hy high pressure water jets. In some of the older plants where manual cleaning still continues the frequency with which men have to go into the autoclave has been reduced very considerably (about once per shift). In L970, Professor Viola of Solvay in Italy became interested in this condition and tried to reproduce It in animals, by exposing rats to very high concentrations of VCM (i e 30,000 parts per million). He failed In this particular objective purported to show that he had found tumours of the ceruminous gland (and this Is a common site in rats for the induction of tumours) and tumours of the lung. He published his findings in 1971. This work was of course examined and did in fact come into disrepute because of dissatisfaction with the strain of rats that he used, his technique and his interpretation of the findings, A European group of manufacturers in Italy, France and Belgium, with which ICI was associated, took the matter a stage further and sponsored Professor Malton I, Bologna, to carry out further animal experimental work. He exposed rats to VCM at concentrations from L0, (K)f) parts per million down to fifty parts per million and reproduced tlte tumours or the ceruminous gland which Viola had reported. He also discovered angiosarcomata of the liver and nephro blastomata of the kidney. These are extremely rare tumours (for instance,, angio sarcomata of the liver m the U.5. numbers about rwo dozen a year). These tumours were produced at all levels of concentration down to 2SB parts per million, hut there was none at fifty parts per million. Neither were there any tumours detected In his controls or in rats exposed to similar concentrations of vinyl acetate. The next stage was to see if any of these effects could be found in VCM exposed operators, and at the ICI Hillhouse plants a survey of the death certificates of all VCM exposed operators over the last 30 years or so was carried out. This survey included men who had died In service, -pensioners and men who at some time or other had left our employment. Up to the end of 1972 this study showed no statistically significant difference in the cancer death rate of the VCM group and a control population. Neither was there any incidence of the rare tumours of liver and kidney found by Maltoni. tn the Runcorn area records were inadequate to show up VCM exposed employees over the years and so the causes of death of all pensioners and those employees dying in service were examined and no primary tumours of the liver were discovered. An investigation is now being carried out to trace the causes of death of those ex-employees who for various reasons left the Company. At this time Maltoni was still continuing with animal experimental work in three main fields. RSV 0000021 :3 i) He was trying to pinpoint more accurately the no effect level In rata by exposing them to levels of 200, 150 and 100 parts per million. il) He was exposing rats m concentrations of 10, OCO down to 50 parts per million for four months only .as this was considered to be equivalent to the working life of an average man. ' . Ui) He was also carrying out a quick test on pregnant female rats to see if he could produce any ill effects in their offspring, ' iv) He was also repeating his original experiment in the rat on hamsters and exposing them to levels of VCM of 10, 000 down to 50 parts per miULon. By this time the Manufacturing Chemists Association in tne USA had become interested in this problem and were doing similar work on the rat, mouse and hamster. The MCA also commissioned a firm culled Tabersbaw Cooper to carry out a survey of causes of death which involved the examination of records of approximately 4, 000 VCM operators. The situation-at Christmas therefore was as follows:* 1) Professor Maitoni had produced evidence that Vinyl Chloride Monomer was carcinogenic to the rat. 2) There was no evidence whatever at that time of any carcinogenic effect In man and indeed the survey carried out at ICI Hillhouse complex had been reassuring, 3) The Tahershaw Cooper investigation was well under way and the results were expected at the end of February and it seemed reasonable to await these results before caking any further action. > On Boxing Day however Dr Johnson of B F Goodrich contacted ICI by telephone and reported that he had found two suspected cases of death from angiosarcomata of the Uver in men who had worked on their Louisville Plant and had been exposed to VCM, [n the next few weeks he reported two further cases from the same plant. [t was of course very necessary to validate the histological findings). All VCM exposed employees on boch/manufacturing sices were informed of the position and a few days later detailed discuss ion a, in which Dr Murray cook part, were held with the shop stewards and supervisors involved in the process. Our customers, the Ministry of Agriculture, Fisheries and Food, and the DHSS, who had been generally in the picture for some time, were brought up to date. The TUC and the Factory Inspectorate were informed of the facts on the 22nd and the 23rd January, 1974 respectively. A press statement was put out by the Company. RSV 0000322 During these few weeks ICI was busy up-datln g its examination of causes of death at Its Hillhouse. Factory and it was during this process that one case of angiosarcoma of the Uver was found. This concerned a pensioner, aged 71, who had worked on the ^ ***" :4: autoclav 'or twenty years-from 1946 to 1966. .Ml concerned were immediately informed of this discovery. , [Cl has established a strong technical team which is new urgently investigating ways and means of reducing exposure to VCM to the lowest possible level. Close conract is being maintained with PVC manufacturers, especially in Europe and the United States. A number of important meetings ar which ICl has Lieen represented have taken place in America and the following is a summary of some of the important points that arose out of these meetings. The first of these meetings was at the MCA headquarters in Washington on 25th January, 1974 when Dr Johnson of B F Goodrich described their four cases of angiosarcoma of the liver. Case 1: Died 1971, aged 33 years with fifteen years' service,. Eight years as an autoclave operator which was followed by a few months working with chemicals such as vinyiidene chloride, vinyl acetate, methanol and ethylene dichloride. He then continued as an autoclave operator for a further six years. Case 2: Died 1973, aged 49 years with 22 years' service. All his service was as an autoclave operator. Case 3: Died 1973, aged 58 years with 29 years' service. He spent eleven years on the autoclaves Ixit there was also exposure to vinyiidene chloride, methanol and' vinyl acetate. After a period of one year In the drying area he then spent a further fifteen years on the autoclaves. t'ase 4: Died 1963, aged 43 years with 19 years' service, lie was emphiycd on (he autoclaves tor seventeen years and during the last nine years nf service was also exposed to vinyiidene chloride, vinyl acetate and methanol. 11 seemed that all four cases of angiosarcoma had I wen exposed, for long periods ro high levels of VCM, Ixst (he a dual levels are not known. Although ft 1- Goodrich have had a number of cases of acro-ostcolysis none of the men who died id' angiosarenma and who were ail autoclave workers had suffered irom this condition. As soon as II F Goodrich Iwd confirmed the finding of deaths from angiosarcomata amongst their employees they informed NfiOSH of the situation who immediately set up a special committee with a view to making recommendations concerning future work practices. An approach was also made to the Kentucky State Board of Health as this is necessary by Statute. - The Kentucky State Board of Health will now await NIOSH recommendations. gSV 0000823 Employees on the effected plant were seen by plant management and told of the situation, Ta tier shaw-< 'nope r were hrought in to carry nut ;:n tn "depth investigation Into the records of all VCM/PVC employ ues - past and present - including a plant atNiagara, which although now dosed was their first plant. An account was given at tills meeting of the work being carried out liy Tabershaw- Cooper, To dace 4,400 record** mve been examined. So tar 122 deaths have been identified and 102 death certificates obtained. A further l, 600 to 1, 800 records are outstanding with an expi cted 30 to 40 more deaths to be investigated. It is now known that this work is not Likely to lie completed before April. No death suspected as being due to angiosarcoma of the liver has been identified although it is admitted that the remaining 1,600 to 1,300 records will cover the older plants. The Manufacturing Chemists Association decided to set up immediately a number of Committees, l> A Medical Committee with a broad remit to investigate any possible means of applying meaningful surveillance. 2) A committee to study work practices (including transport) with the broad remit to reduce exposure. 3) A conwnictee to study methods of analysis*and monitoring. The UK has two representatives (Dr Oick of BP and Dr Duflield of ICt) on the Medical Committee. tCl also has a representative on each of the two other committees. At a meeting in the States on the 14th February Professor Maltoni reported that in the rats that had now lieen exposed to VCM for 12 months he had found a subcutaneus angiosarcoma of neck, 2 angiosarcomata of peritoneum, I angiosarcoma of uterus and 1 angiosarcoma of lung. 2 subcutaneous angiosarcomata hail also been discovered in the twenty week offspring of the pregnant rats which had been exposed to VC.M, On tlie 15th February a tneering was held in die States of the Medical Cam mitt to to consider possible methods of health surveillance. 'Hie following suggest ions were pur forward:- 0 A full medical history ii) A full occupational historv iii> A cancer I vie kg round his'ory RSV 0000824 iv) A physical examination. including xray of both hands and chesi. a *, _ . . :6 : v) Complete blood cornu with plate i! s (? thrombocytopenia). vi) I ivor function teats - !',Uh ulun. SCOT and SGPT, alkaline phosphatese, lactic dehydrogenase. Total blood protein, ulixiniin. blood urea, urine analysis with miscroscopic examination, FEV 1 and FVC. Whilst these latter meetings were in progress uews was received from B F Goodrich of two further coses and it is lielleved that another case has been discovered at Union Carbide* The particulars of these three cases are not yet to hand. This then is the situation up to date. KFW:L 25th February, 1974 RSV 0000825