Document BvVM1bGNpjzDvGndmdMgVrJL8

report of the sub-group oh pcbs To the Chairman, Working Group on Disposal of Toxic end Hacardouo Wastes / INTRODUCTION 1. Vo vare established by the above Working Group in June 19?? In order to, (i) consider whether FCBs should be subject to an authorisation procedure under the proposed legislation (at present lapsed) for the protection of the environment (ii) identify particular problems arising in the disposal of PCBs Ciii) recommend appropriate methods of disposal of waste PCBs ' 'r (iv) submit a Report to the above Working Group incorporating an assessment-, of points (l)-(ili) above, describing hov and where wastes arise, how they have been disposed of and what their inpaoK has been on the physical and biological environment. 2. The complement of the Sub-group has been'as followsi Chairman: Hr 1 Presti, 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 the Environment Mr H A Voddon Dr p Davies Mr H Pullen Hr R L Stanley Hr Christopher Hr A V Davies Hr G Davies' Monsanto Chemicals Ltd .Marketing Director, RedlapdAurle Ltd alno of Radiand/Purle, attended on one occasion Director, BEAHA Trannmiasion and Distribution Association attended in Mr Stanley's place on one oooasion Chief Pollution Officer, Glamorgan River Authority also^he Glamorgan River Authority filled this position on Hr A V Davies's appointment to a regional water ' authority NEV 0 3 6 8 1 I Hr H Stansfield Hr J Bentley Hr A V Kenny Hr B Osmond Department of Trade and Industry Directorate General, Water Engineering, Department of the Environment of the above Directorate each attended one meeting. The report of the above sub-group now follows* THE HEED FOB SPECIAL ATTfflTIOH 7 The term polychlorinated biphenyls (PCBs) refers to the range of substances in which more than one chlorine atom is substituted into the biphenyl molecule* As manufactured, PCBs are invariably mixtures of compounds chlorinated to varying degrees) tjiey may also contain^tcr-and higherjghenyls and furana. The number of chlorine atoms permolecule ia adjusted to the proposed use, dielectric fluids for transformeFs^beXng more highly chlorinated than those used infsfljalj) capacitors. 4 . It has already been recognised both nationally and internationally in OSCDthat the use and subsequent dispersal of PCBs warrant special attention. Th reasons for this relate to their particular characteristics. PCBs do not occur naturally but ore wholly synthetic substances which ar^ generally very stable (stability increasing with degree of chlorination) and which.persist in the environment for very long periods* Their high fat-solubility and the fact that some are metabolised and excreted only very slowly leads to their concentration and accumulation in th fatty tissues of living organisms* This persistence and accumulation, coupled with uncertainties about long-term effects of ..low concentrations, is the basis of the need for special consideration in disposal of wastea* O and 1*t), 5 * Prior to recent restrictions (paras 13/ PCBs were used extensively as dielectric fluids for transformers and capacitors, as hydraulic fluids, heat transfer agents, / y \ ^ \ lubricants and vacuum pump olls^nd^as plasticisers in adhesives, sealants, paints, e *[plastics and^arbonless copying paper* In consequence they have become widely (but not uniformly) distributed in the environment* Generally the higher levels are found Industrial Oireas, but elaewhere levels are usually very low. Topically, concen trations of less than Q.01 ppb* ore observed in air and Bea water and less than 1 ppb g>-- T t ^ e s r r T --in fresh water poll and submarine sediments usually contain less than 10 ppb, but 6. Aquatic organisms take in PCBs from water and the mean concentration in North Atlantic plankton is about 200 ppb, or more than 20,000 tines the level in the v * 1 ppb la one part per billion (1 billion 1 thousand million) NEV 036813 North Atlantic itself* In the larger invertebrates levels of up to 100 ppb in lobster and 500 ppb in mussels have been found. In fish, higher levels eg 102.000 ppb in herring and 100*1,000 in others, have been reported. Predatory birds living in polluted areas and feeding on aquatic organisms at the end of food chains can accumulate very high concentrations of PCBs* Thus the fish-feeding white-tailed eagle in the Baltic has been found with up to about 200 ,0 0 0 ppb in the whole body, and even higher levels in the liver* Similarly a heron in the UK has been reported with 900,000 ppb of PCBs in the liver* 7 * Han of course eats food derived from animals but in the great majority of foods, PCBa 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 toxlolty of PCBs, it is necessary to distinguish between 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 the toxin, whereas chronic toxicity refers to a condition which is established or recurrent* * 9* The routes of entry of PCBs to man are via respiration,- absorption through the skin and food. The first two may be relevant to acute toxic effects, the latter to chronic effects* The acute oral toxicity of PCBa to mammals and birds is low, with lethal levels being similar to those of DOT. For instance, in the caee of rabbits, the oral (does to kill 50^ of the subjects) is in the range 4 ,000-2 0 ,0 0 0 ppm* whole body weight and the skin MLD (minimum lethal doeo) is in the range 1 ,000- 8.000 ppm whole body weight* 10 . The chronic toxicity of PCBs to man and other mammals is moderate* Tn the "Yusho" incident in Japan, involving consumption of PCB-contaoinated rice-oil, the average 4ose associated with significant clinical symptons In man was about 50 mg/day, but positive effects were recorded for those consuming 5 mg/day over aeveral months. Bosearch is in progress to investigate possible low-level long-term effects. 11*' Certain aquatic organisms are very unusual In that they nay be killed by very low concentrations of PCBs in their environment,' ie in the water) in particular, oertaln species of shrimps have been killed at levels of 1 ppb or leas. This Is a consaquenoe of the upteke, concentration and accumulation of PCBs exhibited by these organisms* * 1 ppm is one part per ailllon NEV 036814  1 2 . Differences in the toxicity of commercial PCBs can arise from the importance of certain of the impurities, notably polychlorodibeneofurans. Those substances may either originate from Impure starting materials or arise ae by-products of the manufacturing process. It is therefore difficult to set permissible levels for PCBs In the various components of the environment! especially In view of the limited data available for humans. Howover, the levels proposed for food in the USA bars already been mentioned (para ?)j in addition the US Environmental Protection Agency has recommended that discharges to water should be controlled so that levels of PCBs in the recipient waters do not exceed 0 .0 1 ppb. EXI5TINQ CONTROLS (a) Use ' `' 13* The UK is party to a voluntary international agreement of the OECD which in essence proposed that PCBs should be used only in closed systems in a limited number of cases 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 aspects of their non-flammability. 1*t. In fact, 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 no adequate substitutes for these uses exist. UK practice therefore falls within the terms of the OECD agreement. Very small 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 pro-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 os * produced or for products containing PCBs. However, In'view of the fact that most manufacturing countries are members of OECD, it may be supposed that Imports would only be supplied for uses coming within the terns of the OECD agreement. (b) Pispogsj. 16 . .The Oslo and London Dumping Conventions to which the UK is a signatory, prohibit I .dumping of .PCBs at sea unless present in only trace quantitios, and the Dumping at Sea \ Bill will enable enforcement of procedures developed for these conventions. In addi I tion, the Deposit of Poisonous Wastes Act 1972 penalises the depositing on land of I poisonous whste which gives rise to an environmental hacard. NEV 036815 17 In the UKi PCBa requiring disposal arise in several distinct areasi these are) (1) manufacturing vastest (ii) Imported vastest (ill) fluids fron scrapped transformers} (It ) dielectrical Material from scrapped large capacitors| (v) dleleotrioal material from scrapped small capacitors| (vi) various materials from uses prior to the 1971 restrictions. Manufacturing wastes 1 8 . Manufacturing wastes, comprising both fluids and fluid-contaminated solid materials, amount to about 4<X> tonnes of PCBs/annum at present. As a result of the voluntary restrii tions on sales and the development of alternative systems which do not employ PCBa, particularly for small capacitors, this quantity Is not likely to inereaee. liquid wastei accounting for about ona third of the total waste in this category, are at present diaposi of by high-temperature incineration (see para 3?). Solid wastes comprise still-bottom residues, contaminated rags, paper, sawdust, Puller's Earth, eto and^faulty capacitors arising at the manufacturing plant. Disposal of these solid wastes poses a technical problem which is dealt with in detail in paras 38-*rt Imported wastes 19 Because sufficient high-temperature incineration facilities are not available In continental Europe, about 290 tonnes of liquid PCBa 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, ie high-tenperature holner&tion, Should be used, rather than inadequate, eg indiecrimlaal dumping. In the absence of adequate facilities in continental Europe , this trade ehould not be discouraged. frwXfigr.fl . 2 0 * PCBs have been used In transformers since ,the 19t>0 s* These particular PCBs 'are the highly-chlorinated, very persistent types. Since 1971, 11 transformers have carried a label, warning users of the need for adequate disposal methods, and one have done so elnoe 19^0. -There is a need for a unified, standard label to be NEV 036816 agreed, and It la preferable that this should be done Internationally. This is being considered by the EEC end othor interested parties. Some manufacturers of transformers have written to ell purchasers of transformers, sven back to those buying in the 19*409, informing them of the need for adequate disposal arrangements. Others might be encouraged to do likewise. 21. She major UK transformer manufacturers are OEC, with factories at Stafford, Broastairs and Walton-on-ThamesJ Brush (Hawker-Slddeley) at Loughborought Ferranti at floilinwood, Manchester! and Parsons of Peebles in Scotland. There are alec a number of smaller manufacturers including Bonor Long in Scotland, Pullers at Walthamstow, ACEC in Northern Ireland and Torshlre Transformers, 2 2 . Collectively, these manufacturers use about JOO tonnes of PCBs annum, but the usage is decreasing due to the development of large dry-type transformers and alternative high-duty dielectric flulde such as those based on silicones. However, the higher oosts of dry transformers (up to 6o more than the equivalent fluid- filled unit) and the substantially higher cost of silicone units (up to 5 times more expensive than the conventional type) Is at present retarding a general change over to their use* , 2J. PCB-filled 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 mines. However, the dense fumes which are evolved 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. 2*1. Transformer users are adviqed by the manufacturers to sample the dielectric fluid at regular intervals and to have the eamplo analysed by Monsanto* The fluid may piok up water during service and this may cause dielectric failure, necessitating replacedant of the fluid* Dalton and Co of Belper offer a reclamation service for .$CBs| they have the facilities to recover about 200 tonnes/annum, but at preeent re recovering only about <tO tonneo/annum* This material ooeta about half as much ao new material* Unreolaimable fluids arising from this oourct art disposed of by hightemperature incineration* 2 9 * Die life of large transformers is about >0 years and a faw units, containing a total of about 10 tons of liquid PCBs are scrapped each year at present. These liquids are disposed of by high-temperature Incineration* About JOO units are NEV 0 3 6 8 1 7 currently manufactured eaoh year In UK, of Which about 200 are for the home market. By 1985* about 100 unlts/annum, containing a total of about 130 tons PCBo, may require scrapping; by the year 2000, the level may reach 200 unite/annum, equivalent to 250 tons PCBs. Large capacitors 2$, Poy^r factor correction capacitors are used to smooth out fluctuations in { S / ^ c i ^ ctricajL power ^irculto^and many large factories are equipped with bankp of such capacitors. The principal manufacturers in the UK appear to be BICC, Puttier and Johnson^and Phillips, but a small number of other companies are said to make these types of capacitor on & one-off basis. It is probable that a total of a few thousand of these units are made each week. On average over the last 5 or 6 years, about 600 tonnes of PCBs have been used annually In this application 27. In the UK, each capacitor contains between about 0 .7? and 30 kg of PCBs, the average quantity being about 3kg. Host of this is absorbed on the windings, but a little is present as the free liquid. These capacitors first vent 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 1980s, a number sufficient to give rise to about 130 tons of PCBs will require disposal and by the year 2000 this may rise to about ^00 tons PCBs. Thus these will be more important, in terms of quantity of PCB waste| than transformers. It Is desirable and practicable that'these units should also bo labelled on an Internationally agreed basis as to the need for adequate disposal and this is being discussed* Small capacitors 28. These are generally mounted singly inside equipment such as flourescent light fittings, in the starting systems or fractional horse-power electric motors used in f f j / washing machinoe, air conditioning units^and refrigerator)^and in a range of industrial leetrleal equipment. Each capacitor contains of the order of 50 g of PCBs, the majority of which is absorbed on the paper insulating separator. 2 9 > The principal manufacturers of small capacitors are Pleesey, Pye TMC, PIC, STC :*ni Publler. The larger users have storage tank facilities for PCBs, supplied by tanker, whilst the smaller use drums. About 12 million capacitors are now being produced annually for use in flouroscent light fittings and a total about 60-100 million have been Installed! for electrio motors, the figures are put at ** million and 20-30 million respectively* The total quantity of PCBs used In snail capacitor* baa averaged about 600 tonnee/annua over the last few years, but this lo likely to diminish (para 32)* NEV 0 3 6 8 1 6 ^0 * The ret* of scrapping of these items Tories widelyJ moreover, in the case of washing machines eto the capacitor and aotor is often recovered and reused when the parent equipment Is discarded* Hence it is difficult to estimate a mean life for small capacitors but It is probably between 2 and 10 years* J1* At present the quantity of PCBs in eapaoltora being scrapped is probably about 20 tonnes/annua) this say rise to a peak of about 600 tonnes/annua around 1980 and then fall to about 100 tonnes/annua by 1990, due to the introduction of other fora of dleleotric (see p a n 32), 3 2 * There has been some movemant towards the use of alternative materials in capacitor for flourescent light fittings and this trend has aooelerated very recently. A drytype oapaoitor, based on metallised polypropylene, has been introduced and is currently used in about $% of new fitting, even though It is at present about 10# more expensive than the PCB-filled typo. One company now uses only the new dry-type capacitor for 220 volt fittings and will be doing the sane for W o volt fittings shortly. It has been predicted that the use of PCB-filled capaoltors In this application may be dis continued entirely within the next 3-5 years. There is also some evidence that the use of oapaoitor-start motors In domestic appliances is diminishing, due to changes in-design, automatic washing machines now employing diroot-current motors and refrigerators using package cooling units. 3 3 . Removal of PCB-filled capaoltors iron eaoh separate item of electrical equipmont prior to scrapping is not practicable. These Items are at present disposed of in a variety of ways! t (l) by local authorities using land fill idler# there is no recovery for scrap, the item being simply burled at the base of tipping face. Here it has been observed that motors (and thus capacitors) have sometimes been removed before disposal (ii) by local authorities at a depot (le treatment or transfer plant) where 'i there is recovery and disposal of the electrical equipment to a scrap merchant v. , (ill) by the normal scrap merchant; ferrous scrap is either baled and sent dlreot to a steelworks or to a fragaentation plant. In the latter case (which nowadays la more asuni), the fragmented scrap is cleaned (sometimes by incinera tion at low temperature) and separated magnetically into ferrous and non-ferrous metals. NV 036819 3 h. It boa pot boon possible to obtain quantitative Information about what proportion of small capacitors is disposed of by eaob of the above methods. However, the PCB contents of those which undergo metal processing in a steel blsst furnace, where temperatures reach 1600C, will be destroyed and detoxified* Of those undergoing non-ferrous recovery, the PCB content will almost certainly be distilled in the ataosphore although some degradation may occur. And finally, the PCB content of those undergoing,landfill will only be leached cut when the sealed casing of the capacitor 1 ruptured, and then only very slowly, since little free liquid Is present. These particular PCBs are less highly chlorinated than those used in transformers and are more readily degradable* Miscellaneous 3?* Prior to the voluntary restrictions of 1 971, PCBs were used in a wide variety of applications (para 3 ) In consequence both liquid PCBs and PCB-contaminated materials to be disposed of are still arising'from these sources, and may continue to do so for oorao time yet* The total quantity of PCBs in this category disposed of by incineration since the inception of the Deposit of Poisonous Wastes Act 1972 is about 100 tonnet. METHODS OF DISPOSAL Principles o M 3$ The objective of disposal methods mist be to avoid unnecessary and uncontrolled dispersal of PCBs* The Oslo and London Dumping Conventions, to which the UK is a signatory, already prohibit dumping at saa, unless present in trace quantitiesi and the deliberate disposal of PCBs to the sea, to estuaries, rivers and severs cannot be knowingly permitted* While, Ideally, controlled discharges should also be free from PCBs, it Is inevitable that therb will be low oonaentrations in the dischargee from plants manufacturing and handling PCBs* In such cases, levels in the discharges should ba controlled so that levels in the recipient waters do not exceed 0.01 ppb, as aoommended by the Environmental Protection Agency* * H&T /C Incineration facilities'- fluids \ ` *. * * , * 37* Tbs only proven adequate process ensuring destruction and detoxification of liquid PCBs is high-tempeyatur* incineration. At present there is only one high-temperature Incineration plant available for use in the. UK servicing the waste-disposal industry oapabls of offactively disposing of liquid PCBs, that of Redlond/Purle at Rain**'m, NV 036620 Essex* Bar the end of the Tear another will be eosalssloned, and we understand that another 2 or J nay become operational In the near future* These facilities burn liquid organic wastest including PCBa, at a temperature of about 1200C, high enough to convert K 8 # to OOjg, B and HC1. The first two vapours are of relatively low or negligible environmental lapsot) HC1 is removed fron the effluent by scrubbing, ensur ing fUll compliance with the standards of the Alkali Act* The PCSs are therefore effectively deetroyed and detoxified. The total available eapaolty In the OK for ?flh-tenperature incineration of liquid organio wastes will be 20,000 iain**famua by the end of 1 973 of which oa* 609f ebuld be chlorinated wastes* Hence these facilities will bo adequate to provide for disposal of the quantities likely to srise at least up to the end of this century* The site cost of disposal by this etbod is typically at present about fclO-fJO/ton, the upper limit being applicable to the more highly chlorinated substances\ ooUsotion and transport costs which hare to be added will vary of course with distance of the source from tha plant* Incineration facilities - solids " j8. One possible disposal method for solid FCB^contaminated wastes involves a pre liminary stage of volatilisation of the PCS eontent, followed by colleotion of the fluid and incineration in the available Luid incineration plant. Unfortunately, technical problems have arisen with this method* Combustion of the evaporating PCBg occurs within tbs heating ovens, resulting not only in uncontrolled emissions but also in explosions, which are dearly 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 bars been made to lnolnerate PCB-contaminated solids* 9 9 There are throe types of solid wastes requiring disposali these are (i) Mstill-bo(toa residues'1'fron the PCB-manufacturing process, materials ranging In constitution from tars to glasses and amounting to about 230 tonnee/anmiu -v * paper windings from small capacitors, in particular those arising in large .V.Jjdantlties In faulty oapacltors at the capaoltor manufacturing or handling plant (ill) contaminated rags, sawdust, Fuller's Earth sto, arising at manufacturing and handling plants. ` 4 0 * Home of these oan be disposed of at present by hlgh-teapermture incineration* This Is not a problem in the ease of (ill), since the quantities are very small nd NEV 036621 landfill is an adequate disposal method. For (ii), the problem is a diminishing one, since PCD-contalning small capacitors are being replaced by alternative types. How ever, there is now a backlog, accumulated over the last 18 months, of about 100 tonnes of faulty units requiring disposal. Finally, category (l), still-bottom residues, represent a low volume, high-hazard waste requiring destructive disposal for which no adequate technology exists at present. 41 . The oost of research into alternative methods of disposal for still-bottom residue! is likely to bo considerable, perhaps 5 0 ,000-100,000. One possibility Involves the use of waste solvents, eg toluene, to get the residues into solution (and thus com bustible in the fluid-lnolneration plant), but this is best done at the end of the manufacturing process, not on material already set glass-llke 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 scale on the development of alternative technologies. Finally, the hearth-type kiln 'being developed by Rechem.litd is being investigated for its ability to* destroy the PCB content of contaminated solids. RECOMMENDATIONS 42. In view of the evidence now available concerning the action and distribution of PCBs, we recommend that their use and disposal should be subjeot to epecial considera tion. Use 43 . Ve regard tho-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 ore most likely to eome froa 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 PCBs and PCB-contalning products from non-OECD countries should be subject to control by licence. 44. At present, it 1b not profitable to recover and re-use FCBs from aome applica tions, but the situation may change. Those recovered PCBs fall outside the scope of the present voluntary scheme. -In addition, another manufacturer could at anytime commence manufacture or PCBs. Whilst In both these oases, subsequent uses should be covered by the OECD agreement, they would not be covered by the present manufacturer'a rather more restrictive voluntary scheme. We therefore recommend that the present arrangements should continue but be kept under review. NEV 036322 Disposal - 1 1 guide 45 A method of disposal of liquid PCBs that is known to be safe is high-tenperature incineration and we therefore recommend obligatory disposal of liquid PCBs by this method* This recommendation thus applies to liquid manufacturing and imported wastes and liquid from transformers and large capacitors* Approved incineration plants will be specifically licensed for this purpose* We recommend that facilities should be provided for analysis of stack gases to be carried out at frequent intervals* A realistic figure for stack emissions of PCBs, based on experience gained at manufactur ing plants, is a concentration of lmg/m^, with a total overall emission limit of 0*? kg/day for each si^[e* 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 the 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 analysl 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 system will prove effective when such equipment becomes obsolete* Hov/ever, there is a potential problem associated with disposal of unlabelled first-generation equipment* Borne retrospective iabelllng 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 ve regard the retrospective labelling exercise as all that can practically be achieved. How e v e r , we regard as desirable the compilation of a register of transformers containing PCBs, since this will aid in future identification* Disposal - solids k ? The most difficult disposal problem for the solid PCB wastes arise with the stillbottom residues* These must not be disposed of by methods which are not destructive, eg landfill, but cannot yet be successfully incinerated* We therefore 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 facilitie should be registered and licensed for this specific purpose, and the site conditions with regard to monitoring and supervision should be specified* This recommendation may be taken as a general principle for any hazardous low volume waste for which no NEV 036823 adequate disposal technology existsx namely that it is preferable to store safely and securely until adequate methods of disposal are developed than to disperse the' e waste in an uncontrolled way* 48. The other two categories of PCB-contaminated solids requiring disposal are small capacitors and ragS) paper* sawdust etc from manufacturing and handling plants. Where capacitors remain on the equipment on which they are used| we consider it acceptable that they should be disposed of by landfill* ie 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 themselTOs^tas 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 incineration at high temperature. However, a method for solids is not yet satisfactorily developed; these capacitors could therefore either be stored, as for still-bottom residues, or be disposed of by landfill* In view of the fact* that the numbers of capacitors arising for disposal is likely to diminish rapidly as alternative dielectric materials come into use, we consider storage unnecessary. However, ve recommend that disposal of such capacitors, includ ing the backlog mentioned above in para 40, be a licenced procedure, to be carried out to ensure dispersal of these units to as many available and suitable tips as possible. This will avoid unnecessary concentrations arising at any particular tip. We further recommend that a record be kept of the quantities of these capacitors, and their PCB contents, going to each individual tip. Transportation ^49* The carriage on land of waste liquid PGBs 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 Committee 15, Working Group 0/2 of the Conference Internationale des Grandes Reseaux Electriques a Haute Tension (CIGRE); this would form the basis for an internationally acceptable procedure. Analogous substances 50. Substances such-as alkylated chlorobiphenyls and polychlorinated terphenyls (PCTs) aro structurally similar to PCBs and have comparable properties. They have, as yet,-only very restricted uses in the UK and are not manufactured here. .They NEV 036624 do not come within tho terms of tho OSCD agreement on PCBs and there are no controls over their import* We feel that in particular, these substances should be subject to the same constraints in use and disposal as we recommend for PCBs* . hut positive proposals will depend on whether their use expands* Ve recommend that they be kept under review* (Signed) I Prestt (Chairman) D Davies M Stansfiold H A Vodden R L Stanley G Davies d Bentley J P Giltrow (Secretary) . j . !* '> * NEV 036fl5