Document 8RGQz59NDoZnzp4EpqO8DZJ5a

REPORT OF THE CUU-GROUP ON PCBS To tho Chairman, Working Uroup on Disposal of Toxic and Hazardous Wastes INTRODUCTION 1. Wo wore established by the above Working Group in June 1973 in order to: (i) consider whether PCBs should be subject to an authorisation procedure under the proposed legislation (at present lapsed) for the protection of the environment , ' (ii) identify particular probloms arising in the disposal of PCBs . (iii) recommend appropriate methods of disposal of waste PCBs (iv) submit a Report to the above Working Group incorporating an assessment of points (i)-(iii) above, describing how and where wastes arise, how they have been disposed of and what their impact has been on the physical and biological environment. 2. The complement of the Sub-group has been'as follows: . Chairman: Hr I Prestt, Central Unit on Environmental Pollution, Department of the Environment} at present Deputy Director, Nature Conservancy Council Secretary: Mr J P Giltrow, Central Unit on Environmental Pollution, Department of tho Environment Mr H A Vodden Dr D Davies Mr 1! I'ullen Mr K L Stanley Mr Christopher Mr A W Davies Mr 0 Davies Monsanto Chemicals Ltd Marketing Director, Rcdland/Purlc Ltd also of Redland/Purlo, attended on one occasion Director, BEAKA Transmission and Distribution Association attended in Mr Stanley's place on one occasion Chief Pollution Officer, Glamorgan River Authority also of Glamorgan River Authority flllod this position on' Mr A W Davies's appointment to a regional water authority MONS 043444 Mr H Utnnoficld Mr J Hentley Mr A W Kenny Mr R Osmond Department of Trade and Industry Directorate General, Water ^nginocring, department of the Environment of tho above Directorate each attended one mooting* The report of tho above nub-group now follows* \ TKK 2H&U h'ON UI'KUIAL ATTENTION 3* The term polychlorinated biphenyls (I'CHs) refers to the range of substances in which more than one chlorine atom is substituted into the biphenyl molecule* As manufactured, PC13r uro invariably mixtures of compounds chlorinated to varvinr and may do so today by accident. degrees; they have also contained tor-andhigher phenyls und furans / The number or chlorine at^mnrjc^^molecule is adjusted to the proposed use, dielectric fluids for trannformers/boing moro highly chlorinated than those used in capacitors* 4* It has already been recognised both nationally and internationally in OrJCD that the use und subsequent disposal of VCBs warrant special attention. The reasons for this relate to their particular characteristics. ICIis do not occur naturally but are wholly synthetic substances which are generally very stable (stability increasing with degree of chlorination) und which persist in the environment for very long periods. Their high fat-solubility and the fact that some arc metabolised and oxcroted only very slowly leads to their concentration and accumulation in the fatty tissues of living organisms* This persistence and accumulation* coupled with uncortaintien about long-term effects of low concentrations, in the basis of the need for special consideration in disposal of wastes. and 14), 5*. Prior to recent restrictions (paras 13/ were used extensively as dielectric fluitln for transformers and capacitors, as hydraulic fluids, heat transfer agento, lubricants and vacuum pump oils, as plasticisers in adhesives, nealunts, paints and plastics and/carbonlcss copying paper. In consequence they huve become widely (but not uniformly) distributed in the environment. Generally the higher levels arc found in industrial ureas, but elsewhere levels arc usually very low. Typically, concen trations of lenni than 0.01 ppb* uro observed in air and sou water and less than 1 ppb in frenh water; noil and submarine sediments usually contain less than 10 ppb, but up to several hundred thousand phapso-/bneeeanr osobmseervineddustrial out,,fa.l,,ls i,n .the uiA. 6. Aquatic organisms take in 1 CUn from water and the mean concentration in North Atlantic plankton in about ?.(X) ppb, or more than 20,OK) times the level in the 1 nnh rmrt. rw*r billion (l billion s 1 thousand million) HONS 043445 Worth Atlantic itnclf. In the larger invertebrates levels of up to ICO ppb in lobster and 500 ppb in munnclc have been found. In fish, higher levels eg 1Q2,000 ppb in herring and 100-1,000 in others, have* been reported, Predatory birdst par ticularly thooo feeding on birds and on aquatic organisms at the end of food chains oan accumulate vory high concentrations of IClin. I'hun the fioh**fccdinr white-tailed englo In the Baltic has been found with up to about 200,000 upb in the whole body, and even higher levels in the liver. Similarly a heron in the UK has been roported with 900,000 ppb of PCBs in the liver. 7* Han of courno cats food derived from animaln but in the great majority of foods, PCBs are generally well below 50 ppb in the UK. The American Food and Drug Administration have set interim levels for safety ranging from 200 ppb for special infant and Junior foods to 5*000 ppb for poultry and the edible portions of fish and shellfish. 8. In considering the toxicity of PCBs, it is necessary to distinguish betweon acuto, chronic and long-term toxicity. Acute toxicity refers to a condition coming rapidly to a crisis, usually as a result of a single ingestion of a massive quantity of tho toxin, whereas chronic toxicity refers to a condition which is established r recurrent. With long term toxicity, it may be a matter of years before any effect becomes apparent. 9. The routes of entry of PCBs to win are via respiration, absorption through the akin and food. 'The first two are^^&V&nt to acute toxic effects, the latter to chronic effects. The acute oral toxicity of PCBs to mammals and birds is low, with lethal levels being similar to those of D;/f. For instance, in the case of rnbbite, tho oral (dose to kill 50&* of the subjects) io in tho range '1,000-20,000 ppm* whole body weight and tho skin HLD (minimum lethal docs) in in tho range 1,000 8,000 ppm whole body weight. 10. The chronic toxicity of PCBs to man and other mammals ir. moderate. In tho "Yuaho" incident in Japan, involving consumption of PCIi-contamin.itcd rice-oil, tin average done associated with significant clinical symptoms in man war, about 50 ng/day, but positive effects were recorded for those consuming 3 mg/day over several months. Henearch io in progress to investigate possible low-level long-tor' effects. 11. Certain aquatic organisms are very ununual in that they nuy bo killed by very low concentrations of PClio eg in laboratory trials certain species of nhrimps have boon killod at levels of 1 ppb or less of PCB in tho water. This is a consequence of tho uptake, concentrations and accumulation of PCBs exhibited by those organisms. 1 ppm in one part per million. HONS 043446 1?. Dift'erencon in the toxicity of commercial PCBe can arise from the presence of vary*** /certain oS the impurities, notably polychlorodibcnzofurunn. These aubntuncea may either originate from impure starting materials or arise as by-producta of the manufacturing process* It is therefore difficult to set permissible levels for 1'CHn in the various components of the environment, especially in view of the limited data available for humans. However, the levels proposed for food in the USA have already been mentioned (para 7); in addition the Uo Environmental Protection Agency has recommended that discharges to water should be controlled so that levels of PCi>o in tho recipient watern do not exceed 0.01 ppb. EXISTING CONTROLS (a) Use 1>. The UK is party to a voluntary international agreement of the OECD which in esnonco proposed that PCBs should be used only in closed systems in a limited number of casco where the risk of contamination of the environment is outweighed either by the fnct that no adequato substitutes exist for particular applications or by the considerable advantages associated with their use in special areas, eg the safety aspects of their non-flammability. practice* the sole manufacturer of PCBs in the UK, Monsanto Chemicals Ltd, has since 1971 imposed its own restrictions, supplying PCBs to the electrical industry only, for use solely as dielectric fluids in transformers and capacitors. At present transformers and large capacitors no adequate substitutes for use in / exist. UK practice therefore falls within the terme of tho OECD agreement. Very email quantities of PCBs are also provided for research projects related to transformers and capacitors and also for analytical and toxicological studies. The likelihood of supplies reaching industry for other uses from unused pre-1971 stocks is thought to be minimal and in any case must be diminish ing. ` 1*> There is no information on possible imports of PCBs, either for material as producod or for products containing PCBs. However, in view of the fact that most manu.fac. tur.ing ' coun. tri.es are mem^bers o,f O_E_C_D, ,it may be supposed thaftr.oimmpothretss/ew, osuoxurtrces only be supplied for uses coming within tho terms of tho OECD agreement. There are manu facturing units in eastern European countries which are not partiep to tho OECD agreement and reciprocal trade between theso countries and UK might include PCBs or PCU-containia ZTT , (b) Disposal ` HONS 043447 16. Tho Colo and London Dumping Convent ions ,to which the UK is a signatory, prohibit dumping of I'CHs at sea unless present in only truce quantities; and the Dumping at Sea Dili will enable enforcement of procedures developed for these conventions. In addi tion, the Deposit of Poisonous Wastes Act 197? penalises the depositing on land of poisonous waste which gives rioc to an environmental hazard. CB WASTES 17. In tho UK, PCBo requiring disposal ariso in savernl distinct aroas: theaa are; (1) manufacturing wastea; (li) imported wastes; (iil) fluids from scrappod transformers; (It) dieloctrical material from scrapped large capacitors; (v) dieloctrical material from scrappod small capacitors; (vi,) various materials from uses prior to the 1971 restrictions, . , Manufacturing wastes 18. Manufacturing wastes, comprising both fluids and fluid-contaminated solid materials, amount to about 400 tonnos of PCBs/annum at present. As a result of the voluntary restric tions on sales and the development of alternative systems which do not employ PCBs, particularly for small capacitors, this quantity is not likely to Increase. Liquid wastes, accounting for about one third of the total waste in this category, are at present disposed of by high-temperature incineration (see para 36). Solid wastos compriso still-bottom residues, contaminated rags, paper, sawdust, Fuller's Barth, etc and faulty capacitors arising at the manufacturing plant. Disposal of these solid wastes poses a technical problem which is doalt with in detail in paras 37-40. Imported wastes 19. Because sufficient high-temperature incineration facilities are not available in continental Europe, about 250 tonnes of liquid PCBs are imported into UK each year for disposal by Incineration. Whilst import involves transportation of large quantities of PCBs, and thus some risk of accidental spillage, it is preferable that adequate methods, is high-temperature incineration, should be used, rather than inadequate, eg indiscriminate dumping. In the absence of adequate facilities in continental Europe , this trade should bo accepted. Transformers 20. PCBs have been used in transformers since the 19^00. These particular PCBs are the highly-chlorinated, very persistent types. Since 1971, all transformers have carried a labol warning users of the neod for adequate disposal methods, and some have done so since 19^0. There is a need for a unified, standard label to be HONS 0434W aRrccd, and it io preferable that this should be done internationally. This Is being considered by the KHC and other interested parties* Home manufacturers of transformers have written to all purchasers of transformers, even back to those buying in the 1040n, informing them of the need for adequate disposal arrangements. Others might be encouraged to do likewise. 21, There ore ten UK transformer manufacturers whose collective use of PC3s is about 200 tonnes/annum but the usage is decreasing due to the development of large dry-type transformers and alternative high-temperature silicone dielectric riuidr,. However, the higher costs of dry transformers (up to 60# more than the equivalent fluidfilled unit) and the substantially higher cost of silicone fluids (up to 3 times more exp* inive than the conventional PCBs) is at present retarding a general change over to their use. 2. PCU-fillcd transformers are used principally where there would be serious con sequences if a flammable dielectric were to ignite, eg in ships, basements of buildings and, in continental Europe, in minea. However, the dense fumes which are ovolvod when they become overheated make them unacceptable for some similar applications, eg in the London Transport Underground system, where there is an internal restriction against their use. They are not used in coal mines in the UK for technical reasons. 22* Transformer users are advised by the manufacturers to somplo the dielectric fluid ut regular intervals and to have the sample annlyned by Monsanto. The fluid may absorb water during service and this would lead to dielectric failure, it is some- timon xiocoasar Dalton and Co of Helper offer a reclamation service for PCIta; they have the facilities to recover about 200 tonnes/annum, but at present aro recovering only about 40 tonnes/annum. This material coots about half as much as new material. Unrcclaimable fluids arising from this source are disposed of by high- temperature incineration. , 24. The life of large transformers io about 20 yearn and a few units, containing a total of about 10 tonn of liquid l'Ciis are scrapped each year at present. These liquids are disposed of by high-temperuturc incineration. About 200 units are MONS 043449 currently manufactured each year in UK, of which .about 200 are for the homo market. Uy 1985, about 100 unito/annum, containing a total of about 130 tons TCHn, may require scrapping; by the year 2000, the level may reach 200 unito/annum, equivalent to 2^0 tona PCHn. Marge capacitors 25, Tower factor correction capacitors are used to neutralise or reduce the inductive component of the loud current in power circuits and thus reduce the maximum demand on the power supply system. Many largo factories are equipped with banks of such capacitors and the four UK manufacturers have used on avorago over the laot 5 or 6 years about 6C0 tonnes of PCD* annually in this application. 26. In the UK, each capacitor contains botween about 0.75 and >0 kg of TCttn, tho avorago quantity being about 3kg. Moot of this is absorbed on the windings, but a little is present as the free liquid. These capacitors first went into service in tho late 1950s, but because of their long life (about 25 years), very few have yot been taken out of service. However, by the I980n, a number sufficient to give rise to about 130 tonnes of i C'dc will require disposal and by the year 2000 this may rise to about J|Q0tonnes TCBs. Thus these will bo more important, in terms of quantity of 1'CB waste 1 than transformers. It is desirable and practicable that these units should also be labelled on an internationally agreed basis as to the need for adequate disposal and this is being discussed* Small capacitors 27* Those are generally mounted singly inside equipment such as flourcncent light fittings, in tho smarting nystenn of fractional horse-power electric motors used in washing machines and air conditioning units and in a range of industrial electrical equipment. Bach capacitor contains of the order of 50 g of PClfo, the majority of which in absorbed on the paper insulating separator. 20* There are 8 UK manufacturers of small capacitors and the larger users have storage tank facilities for PCJs, supplied by tanker, whilst tho smaller use drums. About 12 million capacitors are now being producod annually for use in flourcscent light fittings and a total about 60-100 million have been installed: for electric motors, tho fi.gureo are put at million and 20-30 million respectively. The total quantity of PCBa used in email capacitors has averaged about 600 tonnec/annum over tho last few years, but this is likely to diminish (para 31). HONS 043450 t 29, T)io rate of scrapping of those itomo varies widely: moreover, In tho cnoe of washing machines etc tho capacitor and motor is often recovered and reused when the parent equipment la discarded. Hence It la difficult to estimate a mean life for email cupacitors but it is probably between 5 and 10 years, 30* At present the quantity of TCDs in capacitors being scrapped is probably about 290 tonnofi/annum; this may rise to a peak of about 600 tonnes/annum around 1980 and thon fall to about 100 tonneo/ammm by 1990, duo to the introduction of other forms of dielectric (see para ) 1, There has been some movement towards the use of alternative materials in capacitors for flouroecont light fittings and this trend has accelerated very recently. A dry- typo capucitor, baaed on metallised polypropyleno, lias been introduced and is currontly used in about 5% of new fittings, even though it is at present about 10& more expensive More than than the PCB-filled type, /one company now uses only the ,new dry-type capacitor for 220 volt fittings and will be doing the same for MtO volt fittings shortly. It has been predictod that the use of PCB-filled capacitors in this application may be dlsalthough the timo scale*, may now he much shortor than this, oontinued entiroly Within the next 2-p years/ There is also some evidence that the use of capacitor-start motors in domostlc appliances is diminishing, due to changes in design, automatic washing machines now employing direct-current motors and refrigerators using package cooling units, ' ^2* Removal of PCB-filled capacitors from each separate item of electrical equipment prior to scrapping is not practicable* These items are at present disposed of in a varioty of ways: (i) by local authorities using land fill where there is no recovery for scrap, tho item being simply buried at the base of tipping face. Here it has been observod that motors (and thus capacitors) have sometimes been removed before disposal (ii) by local authorities at a depot (ie treatment or transfer plAnt) where thore is recovery and disposal of the electrical equipment to a scrap merchant (ill) by the normul ccrap merchant; ferrous scrap is either baled and sent direct to a steelworks or to a fragmentation plant* In the latter case (which nowadays is moro usual), the fragmented scrap is cleaned (sometimes by incinera tion at low temperature) and separated magnetically into ferrous and non-ferrous metals* HONS 043451 ^ 33. It lias not boon poaoiblo to obtain quantitative Information about what nroportlon / of small capacitoro io diopoocd of by each of the above methods# However, some of the PCB content of those which'undergo ferrous recovery in an arc furnace may be ao rapidly vapourised that undegraded PCB vapour escapes to air. Of those undergoing non-forrouo recovory, the PCB content will almoot certainly be diotillod in the atmoepher although somo degradation may occur. And finally, the PCB content of those undergoing landfill will only be leached out when the cealod casing of the capacitor la rupturod, and then only very slowly, since little free liquid is present. These particular PCBa are lees highly chlorinated than those used in transformers and are more readily degradable. . Miocellencouo 2*4. Prior to the voluntary restrictions of 1971, PCBs were used in a wide variety of applications (para 5)* In consequence both liquid PCBs and PCB~contominated mterials to be disposed of are still arising from these sources, and may continue . to do so for some time yet. The total quantity of PCBs in this category disposed of by incinoration since the inception of tho Deposit of Poisonous Wastes Act 1972 is about 100 tonneo. This figure implies that considerable amounts must have been disposod of by other methods, eg landfill# METHODS OF DISPOSAL . Principles 35* The objoctivo of disposal methods must be to avoid unnecessary and uncontrolled dispersal of PCBs. The Oslo and London Dumping Conventions ' already prohibit dumping at sea, unless present in trace quantities; and the deliberate disposal of PC&s to the sea, to estuaries, rivero and sewers cannot be knowingly permitted. While, ideally, controlled discharges should also be free from PCBs, it is inevitable that there will be low concentrations in the discharges from plants manufacturing and handling PCBs. In such cases, levels in tho discharges should nob be controlled so that levols in the recipient waters do ^constitute any hazard to aquatic life in those waters. On the basis of this principle, the US Environmental Protection Agency has recommended an upper limit of 0.01 ppb. Incineration facilities - fluids MONS 043452 36, The only provenadoquate process ensuring destruction and detoxification of liquid PCBs is high-temperature incinoration. At present there arc two high-temperature Incinoration plant, available for use in the UK servicing tho wasto-dispooal industry capable of effectively disposing of liquid PCBs, those of Pedland/Purle at Rainham, Kcosxt rml at Bllooinoro Port, Cheshire. Wo understand that nnothor 2 or J may bccomo operational in the near future. These facilities burn liquid organic wastes, Including PCBs, at a temperature or about 1200C, high onougli to convert PCBa to CO^, H^O and 1101 Die first two vapours aro of relatively low or I negligible environmental impact; JIC1 is removed from the effluent by scrubbing, ensur ing full compliance with tho standards of the Alkali Act. The PCBs are therefore effectively destroyed and detoxified. The total available capacity in the UK for high-tompernturo incineration of liquid organic wastes was 20,000 tonneo/nnnum at the end of 197?, of which up to ca. Oo'.s could theoretically be chlorinated wastes. (In practice, the proportion is likely to be very much less than this.) Hence these faci lities will bo udequate to provide for disposal of the quantities likely to arise at least up to the ond of this century. The cite cost of disposal by this method is typi cally at present about E10-30/torw,tho upper limit being applicable to more highlyehlori noted substances; collection and transport coats which have to be added will vary of course with distance of the source from the plant. Incineration facilities - solids 57< One possible disposal method for solid rCB-contaminated wastes involves a pre liminary stage of Volatilisation of the PCB content, followed by collection of the fluid and incineration in the available fluid incineration plant. Unfortunately, toohnlcal problems have arisen with this method. Combustion of the evnporatlng TCBs occurs within the heating ovens, resulting not only in uncontrolled emissions but also in explosions, which are clearly dangerous to the operating staff. At present, therefore, this method is not adequate for disposal of solids contaminated with PCBa. It is also known that the rotary kilns operating in the USA have run into similar probloms whon attompts have been made to incinerate PCB-contaminatod solids. j8, Thors are three types of solid wastes requiring disposal: these are (i) "still-bottom residues" from the PCB-manufacturing process, materials ranging in constitution from tars to glasses and amounting to about 250 tonnes/annum (ii) paper windings from small cnpacitors, in particular those arising in large quantities in faulty capacitors at the capacitor manufacturing or handling plant (ill) contaminated rage, sawdust, Fullor'o Barth etc, arising at manufacturing and handling plants. ' MONS 043453 39 Nono of those can be dloposed of at present by high-temperature incineration. Thin is not a problem in the case of (lii), since tho quantities are vo-- and landfill lo an adequate disposal method. For (11), the problem in a diminishing one, since PCD-contninlng small capacitors nro bains replaced by alternative types. How ever, there is now a backlog, accumulated over the last if) months, of about 100 tonnes of faulty units requiring disposal. Finally, category (i), ctill-bottom reeldues, ropresont a low volume, high-haHard waste requiring destructive disposal for which no adequate technology exists at present. certain kO, The cost of research into/alternative methods of disposal for still-bottom residues is likoly to be considerable, perhaps 50,000-0100,000. One possibility involves the use of waste solvents, eg toluene, to get the residues into solution (and thus com bustible in the fluid-incineration plant), but this is best done at the end of the manufacturing process, not on material already set glass-like in a storage drum. Alternatively, it may be possible to reduce the melting point of the residues, but this may create process technology problems. It is not yet possible to set a time scalo on the development of/al?orntfve technologies. However, the hearth-type kiln being developed by He-OiemLtdio being investigated for its ability tO'destroy the PCB content of contaminated solids, and at present, this approuch appears to be very promising. RBCQHMEHDATIONS hi. In view of the evidence now available concerning the action and distribution of PCBa, we recommend that their use and disposal should bs subject to epeelal considera tion. Sat h2. We regard the present voluntary eontrola exorcised by the sole DK manufacturer as satisfactory. This voluntary ayatem cannot control the import of either bulk PCBe or PCB-oontalnlng products, but these are most likely to come from member countries of OECD end should thus be subject to similar restrictions under the OECD agreement. However, we regard it as necessary that import of both bulk PCBo and PCB-contalnlng products from non-OECD countries should bo subject to control by licence. MCNS <H3t5t **3 At present, it is not profitable to recover end re-ueo PCBe from oomc applica tions, but the cituution may change. Those recovered PCBs fell outcide the ecope of tho present voluntary scheme. In addition, another manufacturer could at any tlmo commence manufacture of PCBs. Whilst in both these caoee, subsequent uses should bo covered by the OECD agreement, they would not be covered by the preoent manufncturer'o ruthor more restrictive voluntary ochemo. We therefore recommend that the present arrangemento should continue but be kept under review. Blnpopttl - llnuliis Ml. A method of dlapooal of liquid PCBa that la known to ba safe la hlgh-tonperatura incinoration and ve therefore recommend obligator/ dicpec.il of liquid PCDs by this mathod. Thin recommondatlon thus appliea to liquid manufacturing and imported wastes and liquid from transformers and large capacitors. Approvod incineration plants will be opoclflcally llconsed for this purpose. We recommend that facilities should bo providod for analysis of stack gases to be carried out at frequent intervals. A realistic figure for stack emissions of PCBo, based on experience gained at manufactur ing plants, is a concentration of lrag/m^, with a total overall omission limit of 0.5 kg/day for each site. There ore practical difficulties associated with the methods to be adoptod to ensure those conditions are being met. These ere et present being considered by tho International Electrotechnical Commission (Technical Committoa 10) on which ths UK industry is represented, so ws recommend that if an agreed methodology is proposed by this body, the same should be adopted in the UK for sampling and analysis of stack gases for PCBa. *0. Purchasers of transformoro and large capacitors are informed of the need for adequate disposal and each piece of equipment now sold carries a label to this effect. We think that thia system will prove effective when such equipment becomes obsolete. However, there is a potential problem associated with disposal of unlobellod first-generation equipment. Some retrospective labelling is being carried out) we welcome this and would wish to see this practice universally adopted by manufacturers of this kind of equipment. Ws feel that the probability of large transformers boing obtained by uninformed scrap merchants is minimal and we regard the retrospective labelling exercise as all that can practically be achieved. How ever. , we regard as desirable the compilation of a register of transformers in the UK which contain PCBa, ninca this will aid in future identification. Piopoosl - solids mqns o M>. Ths most difficult disposal problem for tho solid PCB wastes arise with the atlllbottom residues. Tlioao must not ba disposed of by methods which are not destructive, og landfill, but cannot yet be succeasfully incinerated, although the indications are that an adoquato method will shortly be available. Should this not be the cose, we facommend that still-bottom residues be stored in a safe, secure and monitored place until such time as an adequate technological disposal method is devoloped. Storage sites and facilities should be registered and licenced for thia specific purpose, and tho alto conditions with regard to monitoring and supervision should be specified. This recommondatlon may bo token as a general principle for any hazardous low volume vasto for which no y ndcquuto diopooal technology existsi namely that it la preferable to otore eafely and securely until adequato methods of disposal are developed than to disperse the waote in an uncontrolled way. The other two categories of PCB-contaminatcd solids requiring diopooal are emnll copacitors and rogo, paper, sawdust etc from manufacturing and handling plants. Where capacitors remain on the equipment on which they are used, we conoidor it acceptable that they should be dispoeod of by landfill, ie tipping on to dry tipo. This method is also acceptable for the small quantities of contaminated rags otc which arise et manufacturing and handling plants. Where large numbers of capacitors themselves arise (as distinct from equipment using capacitors), eg as faulty Units at manufacturing plants, we had hoped that their PCB content would have boon destroyed during disposal by presently-available incineration equipment. However this method for solids is not yet satisfactorily developed, but the alternative hearth kiln nay prove satisfactory. If this proves to be the case, we recommend that these capacitors bo disponed of by this method; this recommendation includes the backlog of capacitors mentioned above in paragraph 39 If the hearth kiln does not prove success ful in the immediate future, we recommend that such capacitors be stored in a safe and socure placo until tho method is adequately developed. Such sites would require licensing for this specific purpose. Transportation ^8, The carriage on land of waste liquid PCBs should be subject to comparable con ditions in terms of labelling, handling, packaging and transport as are at present voluntarily applied in UK to freshly-manufactured bulk liquid PCBe. A Code of Praotico of this typo is at present being drawn up by Study Committee 15, Working Group 0/2 of the Conference Internationale des Grandee Reseaux Electriquos a Haute Tension (CIGRE); this would form the basis for an internationally acceptable procedure. Analogous substances *9* Substances ouch as alkylated chlorobiphenyls and polychlorinated terphenyls (PCTs) are structurally similar to PCBo And have comparable properties. They have, as yet, only vory restricted uses in the VK and are not manufactured hore. They HONS 043456 do not cone within tho tamo of tha OECD agraomont on TCQs and tharo ara no controls ovor their import. Wa fool that, in particular, these sukotancoo ahould be subject to the aame constraints in use and dinpoeal as we recommend for PCBs, but positive proposals will dopond on whether their use expands. We recommend that they be kept under review. (Signod) 1 Prostt (Chairman) D Davies H Stannfield H A Vodden R L Stanley 0 Davies J Bentley J P Qiltrow (Secretary) '' MONS 043457