Document 0oX1xo1rgwdb79Kx9wdDz9oV

Vr <~&Jl SuJj-- c^tyU vu^itfajL- O.__'b'--(/V\_ With Compliments CC GOTTESMAN HOERUP BRN/SOK RflNNMARK CLAUS THOMAS CLAERBOUT MSB/DR (t( Norsk Hydro Norsk Hydro Polymers Ltd. H M CLAYTON EXECUTIVE TECHNICAL DIRECTOR 28 OCTOBER 1987 Ayclitfe Industrial Estate Newton Ayclitfe Co. Durham DLS 6EA Registered in England No. 1631120 Telephone National: Ayclitfe f03251315122 I nternat: *44 325 315122 Telex 58322 Fax 0325 319013 received NOV 61987 dr. R.T. GOTTESMAN SPI-01296 these men had first been exposed to VCM at times when occupational exposures v very high: the most recent date of first exposun in an ASL victim was 1966. So what? 11) Vinyl chloride is a human carcinogen - fact that is reflected by the low control limits now in force |3 ppm averaged over a shift, 7 ppm for shorter exposures). (2) All the men studied here were employed on a VCM/PVC process prior to I97S. Verification of the efficacy of control will be best achieved by using existing ASL registers to identify any cases occurring in individuals first employed after 1974. (3| The results of this study do not support a role for VCM in the production of canc :rs other than ASL. (4) While death from ASL occurred in one case only eight years after first exposuri the average time appears to be about 2 3 years after the first exposure. (5) Observation of present control limits an j limitation of VCM levels to as low as is reasonably practicable should ensure th : elimination of any cancer risk as a resul of exposure to VCM in this industry. HSE fTUDY OF VINYL CHLORIDE AND PVC WORKERS 6 Health and Safety Executive Medical Division SPI-01297 Whac'j It all about? In 1974 it was realised that expose.- to vinyl chloride (VCM) could cause a very rare 'orm of liver cancer known as angiosarcoma of the liver (ASL). The link between VCM and "61. was made by a works doctor in the Un ted States because of cases of this rare tumc ur that occurred in the relatively small workforce at one of his chemical plants. The cases were only noticed by the doctor because of the rarity of ASL. Exposure levels in the industry were dramatically reduced over a short oeriod of time, but the question remained as to whether exposure to VCM might also h. ive caused an increase in cases of more corr mon cancers -- an effect which would have peen much less noticeable. Why was this study set up? In addition to the question: 'Did VCM ci use other cancers?' it was necessary to look at how different levels and types of exposi|/re might affect the likelihood of VCM-induded tumours. It was also important to learn more about the course of the disease, how so)n i.'ter exposure it might develop, and wiblether any non-cancerous diseases of the liver might be associated with exposure to the cherHiical. What did the study do? All chemical plants in Britain that had either made VCM or used VCM to produce polyvinyl chloride (PVC) were included ifi the study, iucr.iificatio.'i oetails were noted fpr everyone who had worked on these processes between 1940 and 1974. These workers were traced through the National Health Service Register and death certific, ites obtained for those who died. The numbr r of workers dying from particular causes we e then compared with the number that wc uld have been expected if a sample of similai age, sex and size had been taken from the general population of England and Wales. What were the results? An analysis of u.er 7000 workers was carried out and a paper published in the British Journal of Industrial Medicine in 1977. At that time, although two cases of ASL were identified, no statistically significant excesses of mortality were found. Indeed, for diseases of the heart and lungs, significantly fewer deaths occurred -- a finding we now recognise as the healthy worker effect and which, while variable in degree, is similar in most studies of working populations. What Is the latest situation? For the present analysis, which updates that referred to above, we have included only men who had worked for at least a year and whose occupation was deemed to have exposed them to vinyl chloride/PVC for at least 25% of their working week. These criteria reduced the size of the population studied to 5498 males. There was a highly significant excess of primary liver cancer due to the occurrence of seven angiosarcomas. All of these occurred in men who had at some time been autoclave workers. No other evidence of cancers related to VCM exposure was discovered. Exposure to PVC dust did not appear to increase the likelihood of dying from respiratory disease and the number of deaths from non-cancerous liver disease was not increased. A historical review of occupational exposures suggested that up until the mid 1950s, autoclave workers were exposed to 500-800 ppm VCM and that even in the 1960s and early 70s, autoclave exposures were around 150-500 ppm. For the cases of ASL that occurred, the time from VCM exposure to death ranged from 8 to 33 years. Some of SPl-01298