Document ZB0ea1R1n7yBBbBx8vq3zrxyZ

REPORT OF Tilt; GUB-GROUP ON l'CBS To the Chairman, Working Group on Disposal of Toxic and Hazardouu 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 iat present lapsed) for the protection of the environment , - (ii) identify particular problems arising in the disposal of PCBs (ill) 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: . Chairmant Mr I Prestt, Central Unit on Environmental Pollution, Department of the Environment; at present Deputy Director, Nature Conservancy Council Secretary: Mr J P Giltrov, Central Unit on Environmental Pollution, Department of tho Environment Mr H A Vodden Dr D Davies Mr H Pullen Mr H 1 Stanley Mr Christopher Mr A W Davies Mr 0 Davies Monsanto Chemiculs Ltd Marketing Director, Redland/Purle 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 filled this poaition on Mr A W Davies's appointment to a regional water authority HONS 208569 Mr It Gtanoficld Hr J Hontlcy Mr A W Kenny Mr R Ormond Department of Trade and Industry Directorate General, Water Engineering, Department of the Environment of the above Directorate each attendod one meeting. The report of the above nub-group now follows. 3. The term polychlorinated biphenyls (l'CDc) refers to the range of substances in which more than one chlorine atom is substituted into the biphenyl molecule. As manufactured, i'CUs are invariably mixtures of compounds chlorinated to varvinr , ftn" may do so today by accident, degrees; they have also contained tcr-and higher phenyls and furans / The number of chlorine atoms per molecule is adjusted to the nropoGed use, dielectric fluids for gcta?rui.xy * trannformers/bcing more highly chlorinated than those used in capacitors. U, It has already been recognised both nationally and internationally in O.dCD that the use and subsequent disposal of I'CBs warrant special attention. The reasons for this relate to their particular characteristics. l'CUo do not occur naturally but ore wholly synthetic substances which are generally very stable (stability increasing with degree of chlorination) and which persist in the environment Tor very long periods. Their high fat-solubility and the fact that some arc metabolised and oxcrcted only very slowly leads to their concentration and accumulation in the fatty tissues of living organisms. This persistence and accumulation, coupled v.ith uncertainties about long-term effects of low concentrations, is the basin of the need for special consideration in disposal of wastes. and 1A), Trior to recent restrictions (paras 13/ RGBs were used extensively as dielectric fluids for transformers and capacitors, as hydraulic fluids, heat transfer agents, lubricants and vacuum pump oils, as plasticisers in adhesives, sealants, paints and plastics and/carbonlcss copying paper. In consequence they have become widely (but not uniformly^ distributed in the environment. Generally the higher levels are found in industrial ureas, but elsewhere levels are usually very low. Typically, concen trations of Icon than 0.01 ppb* ure observed in air and sea water and less than 1 ppb in fresh water; noil anil submarine sediments usually contain less than 10 ppb, but has been observed , up to several hundred thousand ppb/near some industrial outfalls in the USA. 6. Aquatic organisms take in 1 CDs from water find the mean concentration in North Atlantic plankton in about ?00 ppb, or more than 20,0*10 times the level in the i wti Mn TYiT-r ner billion (l billion * 1 thousand million) HONS 208590 North Atlantic itself. In the larger invertebrates levels of up to 1f,0 ppb in lobster and 500 ppb in nuasoln have been found. In fish, higher levels eg 10 2,000 ppb in herring and 100-1,000 in others, have been reported, i'rcdutory birds, par ticularly those feeding on birds and on aquatic organisms at the end of food chains can accumulate very high concentrations of JCBr,. Thun the fich-fcedin/; white-tailed eagle in the Baltic has been found uith up to about 200,000 npb in the whole body, nnd even higher levels in the liver, similarly a heron in the IJK has been reported with 900,000 ppb of PCBs in the liver. 7. Kan of course eats food derived from animals 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 chcllfish. 8. In considering the toxicity of PCBs, it is nece3iary to distinguish botv/ecn acute, 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 or recurrent. With long term toxicity, it may be a matter of years before any effect becomes apparent. . 9. The routes of entry of I'CBs to win are via respiration, absorption through the skin and food. The first two are/^re^ci&nt to acute toxic effects, the latter to chronic effects. The acute oral toxicity of PCBs to nannuls and birri3 is low, with lethal levels being similar to those of BUT. For instance, in the case of rabbits, the oral (dose to kill 50k- of the subjects) io in the range '1,000-20,000 ppm* whole body weight and the skin ITU) (minimum lethal does) in in tho range 1,000 8,000 ppm whole body weight. 10. The chronic toxicity of PCBs to win and other mamaaln io moderate. In the "Yusho'* incident in Japan, involving consumption of rCh-contaninatcd rice-oil, thi average done associated with significant clinical symptoms in nan war, about 50 mg/duy, but positive effects were recorded for those consuming 3 mg/duy over several monthsPesearch io in progress to investigate possible low-level long-tcr 1 ellects. 11. Certain aquatic organisms are very ununual in that they may be killed by very low concentrations of PCIJg eg in laboratory trials certain species of nhnmps hive been killed at levels of 1 ppb or less of PCB in tho water. This is a consequence of the uptake, concentrations and accumulation of PCBs exhibited by these organism*. 1 ppm in one part per million. HONS 208591 V. ULflrronm in the toxicity of commercial PCBs c.m arise fron the presence of varyir^; /?;t'r'Can Vt the impurities, not.ibly polychloro'Ubcnzofurann, These 3ub.~,tanceo may either originate from impure starting materials or arise ns by-producta of the manufacturing process* It is therefore difficult to set permissible levels for l'CUn in the various components of the environment, especially in view of the limited d.itn mvjliable for humans. However, the levels proposed for rood in the USA have already been mentioned (para 7); in uddition the US Environmental 1'rotcction Agency has recommended that discharges to water should be controlled so that levoln of I'Caa in the recipient waters do not exceed 0.01 ppb. EXISTIPE CONTHOLS * ' (a) Use 1J. The UK ie party to a voluntary international agreement of the OECD which m essence 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 fact that no adequate substitutes exist for particular applications or by the considerable advantages associated with their use in special areas, eg the safety nspoct3 of their non-flammability. 14.,In practice the sole manufacturer of KJBo in the UK, Monsanto Chemicals Ltd, has since 1971 imposed its own restrictions, supplying i'CBs 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 terms of the OECD agreement. Very small quantities of PCBs are aleo provided for reacarch projects related to transformers and capacitors und also for analytical and toxicological studies. The likelihood of supplies reaching industry for other uses from unused prc-1971 stocks is thought to be minimal and in any case must be diminish ing. IJi. There is no information on possible imports of i'CBc, either for material as produced or for products containing PCiis. However, in view of the fact that most . fr,om these, sources manufacturing countries are members of OECD, it may be supposed that importr/wouid only be supplied for uae3 coming within the terms of the OECD agreement. There are manu facturing units in eastern European countries which are not partiep to the OECD agreement and reciprocal trade between these countries and UK might includo PCB3 or PCB-containing products. (b) Disposal 16. The Colo and London Ihimping Conventions?to which the UK is a signatory, prohibit dumping of I'CUs ut sea unions present in only trace quantities/ and the Dumping at iea Bill will enable enforcement of- procedures developed for these conventions. In addi tion, the Deposit of Poioonour- Wastes Act 1972 penalises the depositing on land of poisonous waste which gives noe to an environmental hazard. HONS 208592 17 . In tho UK, PCllo requiring diopooal arioo in several distinct aroao; these are; (i) manufacturing wastes; (ii) imported wastes; (iii) fluids from scrapped transformers; (iv) dieloctrical material from scrapped large capacitors; (v) dieloctrical material from scrapped small capacitors; (vi) various materials from uses prior to the 1971 restrictions* Manufacturing wastes . 4 18, Manufacturing wastes, comprising both fluids and fluid-contaminated solid materials, amount to about i(00 tonnes of PCBs/annum st present* As a result of the voluntary restric tions on Boles end the development of alternative systems which do not employ PCBs, particularly for small capacitors, thia 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 (ooe para 36). Solid waetoB comprieo still-bottom reoiduos, contaminated raga, paper, sawdust, Fuller's Earth, etc and faulty capacitors arising at tho manufacturing plant. Disposal of these solid wastes poses a technical problen which is dealt with in detail in paras 37-^* Imported wastes 19* Because sufficient high-temperature incineration facilities are not available in continental Europe, about 250 tonnes of liquid FCBs 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 adequato methods, is high-temperature incineration, should be used, rather than inadoquate, eg indiscriminate dumping. In the absence of adequate facilities in continental Europe , thia trade should bo accepted. Transformera 20. PCBs huvo been used in transformers since the 19^0s. 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 somo have done so since 19^0. There is a need for a unified, standard label to be MONS 208593 agreed, and it ic preferable that thin should be done internationally. This is being consider'd by the EEC and other interested parties, Hone manufacturers of transformers have written to all purchasers of transformers, even back to those buying in the 1040n, inferring them of the need for adequate disposal arrangements. Otheru might be encouraged to do likewise. 21, Tnere are ten UK transformer manufacturers whose collective use of PC3s is about J00 tonnes/annum but the usage is decreasing due to the development of large dry-type transformers and alternative high-temperature silicone dielectric fluids. However, the higher costs of dry transformers (up to 60i more than the equivalent fluidfillod unit) and the substantially higher cost of silicone fluids (up to 5 times more exp1 wive than the conventional PCBs) is at present retarding a general change over to their use. 22. I'CU-filled transformers are used principally where there would be serious con sequences if a flammable dielectric were to ignite, og in ships, basements of buildings and, in continental Europe, in mines. However, the dense fumes which are ovolved 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 tochnical reasons* 2J. Transformer users are advised by the manufacturers to sample the dielectric fluid at regular intervals and to have the sample analysed by tionsanto. The fluid may absorb water during service and ns this would lead to dielectric failure, it is somcOalton and Co of Helper offor a reclamation service for I'CJis; they have the facilities to recover about 200 tonnon/annum, but at present aro recovering only about 40 tonnes/annum. This material coots about half as much as new material. Unreclaimable fluids arising from this source are disposed of by high- temperature incineration. . 24. The life of large transformers io about JO years and a few units, containing a total of about 10 tons of liquid 1'Cds are scrapped each year at precent. These liquids are disposed of by high-temperature incineration. About J00 units ar-* MOMS 208594 currently nunufactured each year in UK, of which about 200 are for the homo market. By 19U5, about 100 units/annum, containing a total of about 130 tons l'CUn, may require ocrapping; by the year 2000, the level may reach 200 units/annum, equivalent to 250 tono POBa, Marge canacitorn 5, 3'ower 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 powor supply system. Many large factories are equipped with banks of such capacitors and the four UK manufacturers have used on avorago over the lact 5 or 6 years about 600 tonnes of PCBs annually in this application. 26. In the UK, each capacitor contains between about 0.75 and kg of the average quantity being about 3kg. Most of this is absorbed on the windings, but a little is present as the free liquid. These capacitors first wont into service in the late 1950s, but because of their long life (about 25 years) , very few have yet been taken out of service. However, by the 1930s, a number sufficient to give rise to about 130tonnesof 1 C'ic will require disposal and by the year 2000 this may rise to about ij00to*ines i'CBs. Thus these will bo more important, in terms of quantity of i'CU waste, than transformers. It is desirable and practicable that those 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 These arc generally mounted singly inside equipment such as flouroscent light fittings, in the smarting systems of fractional horse-power electric motors used in washing machines and air conditioning units and in a range of industrial electrical equipment* lfiach capacitor contains of the order of l>0 g of PUBr>, the majority of which is absorbed on t.hc paper insulating separator, 28. There jro 8 UK manufacturers of small capacitors and the larger users have storage tank facilities for TCBo, supplied by tanker, whilst the smaller use drums, about 12 million capacitors are now being produced annually for use in flourescont light fittings and a total about 60-100 million have been installed: for electric motors, the figures are put at K million and 20-30 million respectively. The total quantity of PCBo used in small capacitors has averaged about 600 tonnes/annum over the last few years, but this is likely to diminish (para 31). HONS 208595 pg, The rate of scrapping of these Itomo varies widolyi moroovor. In the cnne of washing innchinea etc the capacitor and motor ip often recovered and reuood when the parent equipment is discarded. Hence it in difficult to estimate a mean lifo for email capacitors but it is probably between 5 and 10 years. jO. At present the quantity of TCDe in capocitors being scrapped is probably about 50 tonnefi/tiiuium; this may rise to a peak of about 600 tonnea/onnum around 1980 and then fall to about 100 tonncG/annum by 1990, duo to the introduction of other forme of dielectric (oee para 31). J1, There has been come movement towards the use of alternative materials in capacitors for flourescont light fittings and this trond has accelerated very recently. A dry- typo capacitor, based on metallised polypropylene, has been introduced and is currently used in about 5# of new fittings, even though it is at present about 10# more expensive hare than than the PCB-filled typo, /one company now uses only the .new dry-type capacitor for 0 volt fittings and will be doing the same for MtO volt fittings shortly. It has been predicted that the use of PCB-filled cauacitors in this application ir-ay be diealthouprh the time scale, may now he much shorter than this, continued entirely Within the next J-p years/ There is alno some evidence that the use of capacitor-start motors in domestic appliances is diminishing, due to changes in design, automatic washing machines now employing direct-current motors and refrigerators using package cooling units. J. 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 variety of ways* (i) by local authorities using land fill where there io 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 (iii) by the normul scrap morchant; ferrous scrap is cither baled and sent diroct to a steolworks or to a fragmentation plant. In the latter case (which nowadays is more usual), the fragmented scrap is cleaned (sometimes by incinera tion at low temperature) and separated magnetically into ferrous and non-ferrouo metals. HONS 208596 J3. It lias not been possible to obtain quantitative Information about wliat nroportion of small capacitors is disposed of by each of the above methods. However, some of the rca content of those which undergo ferrouo recovery in an nrc furnace may be so rapidly vapourised thut undegradetl PCB vapour cscapon to nir. Of those undergoing non-ferrouo recovory, the PCB content will almost certainly be diotillod in the atmoophero although somo degradation may occur. And finally, the PCB content of those undergoing landfill will only be leached out when the sealed casing of the capacitor is ruptured, and then only very slowly, since little free liquid is present. These particular PCBs are less highly chlorinated than thoao used in transformers and are more reudily degradable. t Miocolloncoua Prior to the voluntary restrictions of 1971, PCBe were ueed in a wide variety of applications (para 5)- In consequence both liquid PCBs and PCB-contaminated tutorials to be disposed of axe still arising from these sources, and mny continue to do so for some time yet. The total quantity of PCBs in this category dispoced of by incineration since the inception of tho Deposit of Poisonous Wastes Act 1972 is about 100 tonnes. This figure implies that considerable amounts must have been disposed of by other methods, eg landfill. METHODS OF DISPOSAL Principles 33. The objective 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 PCBs to the sea, to estuaries, rivers and sewers cannot bo 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 the dischargee rhould not be controlled so that levels in the recipient wators do ^constitute any hazard to aquatic life in those-waters. On the basis of this principle, the U5 Environmental Protection Agency has recommended an upper limit of 0.01 ppb. Incineration facilities - fluids 36. only proven adequate process ensuring destruction And detoxification of liquid PCBo is high-tomperature incineration. At present there arc two high-temperature incineration plant, available for use in the UK servicing tho waste-disposal industry capable of effectively disposing of liquid PCBs, those of Redland/Purle at kainham, HONS 208597 Ecoex* rntl *'t Ellosmcro Port, Cheshire. Wo understand that ' another 2 or 5 may bccoftw operational in the near future. These facilities hum liquid organic wastes, including FCBo, at a temperaturo of about 1200C, high enough to convert PCBn to CO^, H^O and UC1, Tlie first two vapours aro of relatively low or negligible environmental impact; BC1 ie removed from the effluent by scrubbing, ensur ing full compliance with the standards of the Alkali Act. The PCBs are therefore effectively destroyed and detoxified. The total available capacity in the UK for high-temperature incineration of liquid organic wastes Wfta 20,000 tonneo/annum at the end of 1975, of which up to cu. GO^ could theoretically bo chionnated wastes. (In practice, the proportion is likely to be very much less than this.) Hence these loca lities will bo adequate to provide for disposal of the quantities likely to arise at least up to the ond of this century. The site cost of disposal by thiG method is typi cally at present about ClO-JO/torrc.thc upper limit being applicable to more highly chlori nated substances; collection and tranoport co3ts which have to be added will vary of course with distance of the source from the plant. Incinoration facilities - solids 37* 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, technical problems have arisen with this method. Combustion of the evaporating TCBs occurs within the heating ovens, resulting not only in uncontrolled emissions but also in explosionG, which are clearly dangerous to the operating staff. At present, therefore, this method is not adequate for disposal of solids contaminated with PCBs. It is also known that the rotary kilns operating in the USA have run into similar problems when attempts have been made to incinerate PCB-contaminatod solids. 38, Thors aro 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 snail capacitors, in particular those arising in large quantities in faulty capacitors at the capacitor manufacturing or handling plant (ill) contaminated rags, sawdust, Fuller'g Earth etc, arising at manufacturing and handling plants. ` 59, Mono of these can be disposed of at present by high-temperature incineration. Thio ie not a problem in the case of (iii), since tho quantities ar v*-- nnri MONS 206596 lorulflll is an adequate disposal method* For Cii), the problem la a diminishing one, since PCD-containing small capacitors arc being replaced by alternative types. How ever, there is now a backlog, accumulated over the lost 18 months, of about 100 tonnes of faulty units requiring disposal. Finally, category (i), still-bottom residues, represent a low volume, high-hazard waste requiring destructive disposal for which no adequate technology exiota at present. certain 40. The coot of research into/alternative methods of diapoool for etill-bottom residues is likely to be considerable, perhaps 50,000~i''100,000* One possibility involves the use of waste solvents, eg toluene, to get the residuee 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 tine ..these particular ,, scale on the development of/alternative technologies, However, the hearth-typo kiln being developed by Re-QtemLtd is being investigated for its ability to destroy the PCB content of contaminated solids, and at present, this approach appears to be very promising. RECOMMENDATIONS 41. In view of the evidence now available concerning the action and distribution of PCDs, we recommend that their use and disposed should be subject to special considera tion* fist 42. We regard the present voluntary controls exercised by the sole UK manufacturer as satisfactory. This voluntary system cannot control the import of either bulk PCBs or PCB-containing products, but these are most likely to come from member countries.of OECD and should thus be subject to similar restrictions under the OECD agreement. However, we regard it as necessary that import of both bulk FCdc and PCB-containing products front non-OECD countries should be subject to control by licence. - , 43* At present, it is not profitable to recover and re-uoa FCQe from some applica tions, but the (situation may change. Those recovered PCBs fall outcide the scope of the present voluntary scheme. In addition, another manufacturer could at any tine commence manufacture of PCBs. Whilst in both these caoes, subsequent uses should be covered by the OECD agreement, they would not be covered by the present manufacturer's rather more reotrictive voluntary scheme. We therefore reeom^nrt that the present arrangements should continue but be kept under review. HONS 209599 blnpoaal - Tioulda Mt, A method of diopooal of liquid PCBe that is known to bo aafe ia high-temperature incineration and we therefore recommend obligatory disposal of liquid PCBa by this mothodt This recommondotion thus applies to liquid manufacturing and imported wastes and liquid from transformers and large capacitors. Approved incineration planta will be opecifically licensed for this purpose, We recommend that facilities should bo provided for analysia of otack gases to be carried out at frequent intervale. A realistic figure for 6tack emissions of PC13q, based on experience gained at manufactur ing plants i is a concentration of lmg/m^, with a total overall emission limit of 0.5 kg/day for each alto. There are practical difficulties associated with the methods to be adopted to ensure these conditions are being met. These are at present being considered by tho International Electrotechnical Commission (Technical Committee 10) on which the UK industry is represented, so we 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 PCBs. Purchasers of transformers 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 this eystem will prove effective when such equipment becomes obsolete. However, there is a potential problem associated with disposal of unlabolled 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. We feel that the probability of large transformers being obtained by uninformed scrap merchants is minimal and we regard the retrospective labelling oxorciea as all that can practically be achieved. How ever, we regard as desirable the compilation of a register of transformers m the UK which contain PCBs, oince this will aid in future identification. Diopooal - solids 16. Die most difficult disposal problem for tho solid PCB wastes arise with the still- bottom residues. Those must not be disposed of by methods which are not destructive, eg landfill,_ but cannot yet be successfully incinerated, although tho indications are that an ndoquato mothod will shortly be available. Should this not be the case, we recommend that still-bottom residues be stored in a safe, secure and monitored place until such time as an adequate technological disposal method is developed. Storage sites and facilities should be registered and licenced for thio specific purpose, and tho site conditions with regard to monitoring and supervision should be specified. 'This recommendation may bo taken as a general principle for any hazar,1ft"i low volumo waste for which no MGNS 208600 f f adequate diopocal technology exists; namely that It io preferable to store safely and cecuroly until adequalo methods of disposal are developed than to disperse tho waste in an uncontrolled way. 17. Tho other two categories of PCH-contaminatcd solids requiring disposal are small capacitors and rags, paper, sawdust etc from manufacturing and handling planto. Where capacitors remain on the equipment on which they are u6od, we consider it acceptable that they should be disposod of by landfill, ic tipping on to dry tips. This method is also acceptable for the small quantities of contaminated rags etc which arise at manufacturing and handling plants. Where large numbers of capacitors themoolveo arise (as distinct from equipment using capacitors), eg as faulty units at manufacturing plants, we had hoped that their PCB content would have been destroyed during disposal by presently-available incineration equipment. However this method for solids is not yet satisfactorily developed, but tho alternative hearth kiln may prove satisfactory. If this proves to be the case, we recommend that these capacitors be disposed 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 secure placo until the method is adequately developed. Such sites would require licensing for this specific purpose. I Transportation 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 PCBs. A Code of Practice of this type is at present being drawn up by Study Committoo 15, Working Group 0/2 of the Conference Internationale des Grandes ReBeaux Electriques a Haute Tension (CXGRE); this would form the basis for an internationally acceptable procedure. , Analogous substances **9. Substances ouch as alkylated chlorobiphenyls and polychlorinated tcrphenyls (PCTs) are structurally similar to PCBo and have comparable properties. They have, os yet, only very restricted uses in the UK and are not manufactured here. They HONS 208601 < 1 do not conic within the tcrme of the OECD agreement on PCBs and thcro are no controlo over their import. Wo feci that, in particular, theoo substances should be subject to the same constraints in use and dinposal as we recommend for PCDs, but positive proposals will dopond on whether their use expands. W recommend that they be kept under review. N 'N (Signed) I Prostt (Chairman) D Davies M Stannfield H A Voddcn P L Stanley G Davies J Bentley J P Giltrow (Secretary) i * MONS 208602 -f