Document v6MpXRn6BMkMGByDZLnRvgMkZ

^ -^&-V -5 r '- '. Sew 4 '` ' "*'> '; ' m J 13 June 1074 Comment .',*'< * , C^rf`-i VkJ va , n' j a, y-1' -t-i-'t t, *{ // ^U-*L ^4'ri 1 Missing the vinyl chloride link iy Very soon, Britain's Factory Inspectorate will decide whether workers in the chemical industry should be allowed to inhale a dangerous carcinogen--vinyl chloride monomer (sec p G75). All the indications arc that the inspectorate will favour the argument put forward by the chemical industry, that if exposure to VCM is limited to 25 parts per million, the risk of liver cancer caused by VCM will be acceptably low. The evidence for this reason ing is hardly convincing. It is that the incidence of liver cancer (in this case angiosarcomas) among workers in plants using VCM is very low (so far only 13 workers with angiosarcomas have been found compared with the 8000 or so workers in the US and Britain who are todayexposed to VCM), and that most of the few people who have died from the disease worked in the industry 20 or more years ago. when the levels of VCM in the atmo sphere of chemical plants were considerably higher than they arc today. There is, as yet. no evidence that woyltMlatly contradict this reasoning. There is no "safe" limit of exposure to VCM. A limit can be defined only on the criterion of an "acceptable" risk. Of course, what is acceptable to BI\ ICI, and the other large PVC manufacturers, may well not be acceptable to the workers at risk or their trade unions. The evidence now accumulating indicates that the risk of cancer (and other diseases) caused by VCM may be greater than the industry would have us believe. It is true that few deaths from angiosarcoma have been found so far. But this may well be because the people with angio sarcomas haven't-died yet. The most complete US epi demiological survey (only two out of 257 ex-employees were not located) shows that three out of 24 deaths were from angiosarcoma. Given the fact that the latency period .of the disease may be as long as 25 years, it seems certain that more deaths from angiosarcoma will be discovered in the population of workers exposed to VCM. (There has also been a suggestion that angiosarcoma can be mis diagnosed as cirrhosis of the liver.) Whatever the deadly statistic finally reveals, it will be higher than the ID out of 8000 suggests. There is also every likelihood that VCM (like other carcinogens) causes tumours in more than one organ--indeed, nephroblastomas have already been found in rats exposed to VCM. Perhaps even more disturbing are unconfirmed reports in the New York Times that angiosarcomas have been found in four people not work ing in plants making polyvinyl chloride--implying a mammoth increase in the population at risk. German researchers have suggested that the other disease linked with vinyl chloride--aero-osteolysis--may be clinically more serious and more prevalent than previously thought. A German union (1G Chemie-l'apier-Kerainik) estimates the incidence of the syndrome described by the German researchers as one in three. All this is unfortunately tentative. It does indicate, how ever, i hat the VCM's carcinogenicity will prove a serious problem--much more than a rare, and rather historic, medical anomaly. The implication of this evidence is that workers should not be asked to breathe a substanre which is almost weekly revealed to he more and more dangerous. The chemical 'industry rejects this course, ol action on the grounds that it would mean during down I'VC plants, with possibly disastrous consequences on employment and the economy. But one company, Dow Chemical, has already reduced levels of VCM in a polymerisation plant to 2 or 3 ppm. Certainly, putting a zero exposure limit into practice would be costly--perhaps immensely costly. But if VCM proves as hazardous as can be expected on the basis of preliminary research, that cost is justified. There are also questions broader than the setting of safe limits for exposure to VCM. Vinyl chloride is only one of the myriad of new chemicals that have become commonplace in industry since the post-war boom in petrochemicals. As many ns 500 to 600 new substances are introduced every year, and 25 000 chemicals already in use need to be screened. How many of these arc carcinogenic? Irving Selikoff. an old campaigner for indus trial safety, says. "We can't sec them but we hear them moving about in the forest". In April 1973. Frofessor Ccsare Maltoni prophetically remarked: "Would such (liver cancers; unhappily be found in man... it would be a precise indication of the value of experimental testing in predicting the oncogenic rntcnl:.;.l of environmental agents and would strengthen the-. ecommcfidation on the necessity of such bioassays before any new industrial compound is produced and widespread." The Health and Safety at Work Bill, currently before the British parliament, proposes some such pre-testing of potentially hazardous chemicals. The lethal consequences of breathing vinyl chloride should ron"ince everyone, not least the Commission to be created 'ujr the Bill, that however expensive, screening, is an essential life-saver. Lawrence McCinty 0,f' and seeking new safety thinking Our inability to understand and control new technology before it goes into widespread use was dramatically illus trated by three items in the news in the past two weeks: the Flixborough explosion (sec p 590 last week), the report on the Sumim-rland fire (sec p 634), and new worries about vinyl chloride monomer. But another event last week provided equally dramatic proof of our ability to control our technology if we really want to--the experi mental safety vehicle (KSV) conference in London (sec p G80). When the US government, under pressure from Ralph* J*ader, set apparently arbitrary and extremely strict performance standards for cars, the manufacturers screamed that the standards were meaningless and could not, in any case, be met without building minitanks. But ',>l"yj. '. - - '.'tv-'io- ivit&vT/''* v 1 v it