Document Byxeb2Mq0wzyRLxyrQr7grBQo

REPORT OF THE SUB-GROUP ON FOBS Tq the Chairman, ' Working Group 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 on 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 (iv) submit a Report to the above Working Group incorporating an assessment i- 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. i < 1 i ' 2. The complement of the Sub-group has been*as follows: ', Chairman: Mr 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 H Pullen Mr K L Stanley .Mr Christopher Mr A V/ Davies Mr G Davies Monsanto Chemicals Ltd Marketing Director, Redland/Purle Ltd . also of Redland/Purle, attended on one occasion Director, BEAMA Transmission and Distribution Association attended in Mr Stanley's place on one occasion Chief Pollution Officer, Glamorgan River Authority alqo of Glamorgan River Authority filled this position on' Mr A V Davies*a appointment to a regional water authority NEV 0 3 6 3 0 1 Hr H Gbunoficld Mr J Hentley Mr A W Kenny Hr R Osmond Department of Trade and Industry Directorate General, Water'Engineering, Department of the Environment of the above Directorate each attcndod one meeting* The report of the above nub-group now follows* THK jJliJJj FOR S I'KCIAl ATTKNTION 2* The term polychlorinated biphenyls (PCJis) refers to tjie range of substances iri which more than one chlorine atom is substituted into the biphenyl molecule.' As manufactured, PCDs are invariably mixtures of compounds chlorinated to varvinm and may do so today by accident* degrees; they have also contained ter-andhigher phenyls und furans / The number of chlorine atoraorgjjynolecule is adjusted to the proposed use, dielectric fluids for transformere/being more highly chlorinated than those used in capucitors* hm It has already been recognised both nationally and internationally in OrJCD that the use and subsequent disposal of PCDs warrant special attention. The reasons for this relate to their particular characteristics. PC3s 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 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 the 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 wastes. ^ and 1A), 5*i Trior to recent restrictions (paras 1j/ PCDs 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/carbonlees copying paper. In consequence they huve 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, conceii- . trations of lens than 0.01 ppb# are observed in air and sea v/ater and less than 1 ppb in fresh water; soil and submarine sediments usually contain loss than 10 ppb, but has .been observed .,, . up to several hundred thousand ppb/near some industrial outfalls in the U6A. 6* Aquatic organisms tuko in l'CIio from water and the mean concentration in North Atlantic plunk ton in about ?.00 ppb, or more than 2 0 ,0 0 0 times the level in the j " NEV 036302 .* 1 cm wirt TM*r billion (1 billion = 1 thousand million) North Atlantic itself. In tho larger invertebrates levels of up to 1C0 ppb in lobster and ^00 ppb in muncclc have been found. In fish, higher levels eg 10- 2.000 ppb in herring and 100-1,OCX) in others, have been reported, i'rcdatory birdsf pai ticularly thoco feeding on birds and on aquatic organisms at the end of food chains can accumulate very high concentrations of ICHr.. Thus the fich-fccdin/: white-tailed eagle in the Baltic has been found with up to about 200,000 ppb in the whole body, and even higher levels in the liver, Similarly a heron in tho UK has been reported with 900,000 ppb of PCBs in tho liver. 7. Han of course cats food derived from animals but in the groat majority of foods, PCBs are generally well below 90 ppb in tho UK. The American Pood and Drug Administration have set interim levels for safety ranging from POO ppb for special infant and junior foods to 9000 ppb for poultry and the edible portions of fish and shellfish# 8. In considering the toxicity of PCBs, it is necessary to distinguish botv/een 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 PCBs to man are via respiration, absorption through the skin and food. The first two are/u^\fvimt 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 DDT. For instance, in the case of rabbits, the oral LDj-q (dose to kill 50^ of the oubjocts) io in the range ,0CX)-20,000 ppm* whole body weight and the skin HLD (minimum lethal docs) is in tho range 1,0008.000 ppm whole body weight. 10. The chronic toxicity of PCBs to man and other mammals is moderate. In the "Yusho" incident in Japan, involving consumption of rCU-contaminated rice-oil, th-j average done associated with significant clinical symptoms in nan was about 30 ng/duy, but positive effects were recorded for those consuming 3 mg/day over several months. Hescarch io in progress to investigate possible low-level long-tcrv* effects. 11, Certain aquatic organisms are very unusual in that they nay be killed by very low concentrations of PCBs eg in laboratory trials certain species of shrimps have been killed at levels of 1 ppb or less of PCD in tho water. This io a consequence of the uptake, concentrations and accumulation of PCBs exhibited by these organisms. NEV 036303 1 ppm in one part per million 12, Differences in the toxicity of commercial PCBs can Arise from the presence of varyir^; /cci'Kun oi the impurities, notably polychlorodibcnzofuruns. These substances may either originate from impure starting materials or arise Q3 by-products of the manufacturing process. It is therefore difficult to sot permissible levels for I'Clin in the various components of the environment, especially in view of the . limited data available for Humana However, the levels proposed for food in the USA have already been mentioned (para 7 )i in addition the US Environmental Protection Agency haB recommended that discharges to water should be controlled so that levels of PCBs in the recipient waters do not exceed 0 .0 1 ppb, EXISTING COHTHOLS (a) Use 1J. 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 1 of cases v/here 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 aspect's of their non-flammability. Vu.ln practice * the sole manufacturer of lJCDs 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 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 pre-1971 stocks is thought to be minimal and in any case must be diminish ing. ' 1 5 There is no information on possible imports of PCBs, either for material as produced or for products containing PCBs. However, in view of the fact that most front thoGo courcos manufacturing countries are members of OECD, it may bo supposed that 'imports/wouid only bo supplied for uses 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 include PCB3 or PCB-containi*^ products. (b) Disposal 036304 16. The Oslo and London Dumping Conventions}to which the UK is a signatory, prohibit dumping of i'CHe at sea unless present in only trace quantities^ and the Dumping at oca Bill 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 rise to an environmental hazard. ,'CB WASTES In tho UK, PCBo requiring disposal arise in several distinct aronst these are; (i) manufacturing wastes; ( i O Imported wastes; (iii) fluids from ocrappod 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 1 8 . Manufacturing wastes, comprising both fluids and fluid-contaminated solid materials, amount to about ^0 0 tonnes of PCBo/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 wastes compriso still-bottom reoiduos, contaminated rags, paper, sawdust, Fuller's Earth, etc and faulty capacitors arising at tho manufacturing plant. Disposal of these solid wastes poses a technical problem which is dealt with in detail in paras 37-^0 . 1 9 . 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, la 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. Traneformera 20. PCBs havo been used in transformers since the 19**0 s. These particular PCBs are the highly-chlorinated, very persistent types. Since 1971, all transformers have carried a label warning users of the need for adequate disposal methods, and some have done so since 19**0. There is a need for a unified, standard label to be NEV 03&305 agreed, and it io preferable that thin should bo done internationally. This is being considered by the KEC and other interested parties. Some manufacturers of trannformers have written to all purchasers of transformers, even back to those buying in the informing them of the need for adequate disposal arrangements. Others might be encouraged to do likewise* 2 1 . There 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 60& more than the equivalent fluidfillod unit) and the substantially higher cost of silicone fluids (up to 5 times more oxp* loive than the conventional PCBs) is at present retarding a general change over to their use. 2 . PCU-filled treinsformers 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 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 technical reasons. I * 2 2 * Transformer users are advised by the manufacturers to sample, the dielectric fluid at regular intervals and to have the sample analysed by Monsanto. The fluid may absorb water during service and as this would lead to dielectric failure, it is some times nocossaryiSe1"HteS! Ualton and Co of Belper offor a reclamation service for PCDs; they have the facilities to recover about 200 tonnos/annum, but at present aro recovering only about **0 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* Tho life of large transformers is about JO years and a few units, containing a total of about 10 tons of liquid PCUn are scrapped each year at present. These liquids are disposed of by high-temperature incineration. - About J00 units are NEV 03 6 3 0 6 / currently manufactured each year in UK, of which about 200 are for the homo market. By 190 5 * about 100 units/annum, containing a total of about 130 tons PCUs, may require scrapping; by the year 2000, the level may reach 200 units/annum, equivalent to 250 tons FOBs. barge capacitors Power factor correction capacitors are used to neutralise or reduce the inductive component of `the load 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 average over the last 5 or 6 years about fiCO tonnes of PCBg annually in this application. 2 6 . In the UK, each capacitor contains between about 0 .7 5 and 30 kg of I'Clte, 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 went 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 1JO tonnes of i'CBs will require disposal and by the year 2000 this may rise to about 100 tonnes FCBs. Thus these will bo more important, in terms of quantity of PCS waste1 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* These are generally mounted singly inside equipment such as flourosccnt 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. Each capacitor contains of the order of 50 g of PCBs, the majority of which is absorbed on t.hc paper insulating separator. 2 8 . There are 8 UK manufacturers of small capacitors and the larger users have storage tank' facilities for PCBo, supplied by tanker, whilst the smaller use drums. About 12 million capacitors are now being produced annually for use in flourosccnt light fittings and a total about G0-100 million have been installed: for electric motors, the figures are put at million and 20-./) million respectively* The total quantity of PCBs used in email capacitors has averaged about 600 tonnec/annum over the last few years, but this is likely to diminish (para 51) NEV 0 3 6 3 0 7 29, Tho rate of scrapping of these items varies widely; moreovor, in the case of washing machines eto the capacitor and motor is often recovered and reused when tho parent equipment is discarded. Hence it is difficult to estimate a mean life for small capacitors but it is probably between 5 and 10 years. Vi \ JO. At present the quantity of FCBs in capacitors being scrapped is probably about 250 tonnes/annum; this may rise to a peak of about 600 tonnes/annum around 1980 and thon fall to about 100 tonnes/annum by 1990 duo to the introduction of other forms of dielectric (see para 21)* ? 31, There ha3 been some movomant towards the use of alternative materials in capacitors for flourescont light fittings and this trend has accelerated very recently. A dry- typo capacitor, based on metallised polypropylene, has been introduced and is currontly used in about 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 220 volt fittings and will be doing the same for bbO volt fittings shortly. It has been predicted that tho use of PCB-filled cauacitor3 in this application may be dis- although the time scale, may now he much shorter than this, continued entirely within the next years/ There is also 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. 5 2 Removal of PCB-filled capacitors from each separate item of electrical equipment prior to screpping is not practicable. These items are at present disposed of in a variety of ways: () 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 observed 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 tho electrical equipment to a scrap merchant (iii) by the normal scrap morchant; ferrous scrap is oither baled and sent direct to a steelworks 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-ferrous metals. NEV 036308 33. It lias not boon possible to obtain quantitative information about what nroportion of small capacitors ie disposed of by each of the above methods. However! some of the PCB content of those which'undergo ferrouo recovery in an arc furnace may be so rapidly vapourised that undegraded PCB vapour escapos to air. Of those undergoing non-ferrouo recovery, the PCB content will almost certainly be distilled in the atmosphere 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 rupturod, 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 roadily degradable, i .V Miscellaneous - 3 *1. Prior to the voluntary restrictions of 1 9 7 1 , PCBs were used in a wide variety of applications (para 5 )* 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 some time yet. The total quantity of PCBs in this category disposed of by incineration since the inception of tho Deposit of Poisonous Wastes Act 1972 ie about 100 tonnes. This figure implies that considerable amounts must have been disposed of by other methods, eg landfill. METHODS OF DISPOSAL Principles 35# 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 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 the dischargee should not be controlled so that levels 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 * 36. The only proven adoquate process ensuring destruction iind detoxification of liquid PCBs is high-temperature incineration. At present there are two 'high-temperature incineration plant; available for use in the UK servicing the waste-disposal industry capable of effectively disposing of liquid PCBs, those of Bodland/Purle at Rainham, NEV 03639 Ecoex^ nnd at Bllosmoro Port, Cheshire. Wo understand that another or 2 may bccomo operational in the near future. These facilities burn liquid organic wastes, including PCBs, at a temperature of about 1200C, high enough to convort PCBs to CO^, H^O and JIOI. The first two vapours are of relatively low or negligible environmental impact; HC 1 is removed from the effluent by scrubbing, ensur ing full compliance with the standardo of the Alkali Act. The PCBs are therefore effectively deotroyed and detoxified* The total available capacity in the UK for high-tomperaturo incineration .of liquid organic wastes w^s 20,000 tonneo/annum at the end of 1 9 7 5 of which up to ca. Goi^ could theoretically be chlorinated wa&tcs. (In practice, the proportion is likely to be very.much less than this.) Hence these faci lities will be adequate to provide for disposal of the quantities likely to arise at least up to the end of this century. The site cost of disposal by this method is typi cally at present about lO~3QAonne,the upper limit being applicable to more highlycKlori nntod substances; collection and transport costs which have to be added will vary of course with distance of the source from the plant. Incineration facilities - solids 3 7 1 One possible disposal method for solid FCB-contaminated wastes involves a pre liminary stage of Volatilisation of the FCB 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 PCBs 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 PCBs. It is also known that the rotary kilns oporating in the USA have run into similar problems whon attompts have been made to incinerate PCB-contaminated solids. 28* Thors are three types of solid wastes requiring disposals these nro (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 capacitors, in particular those arising in large quantities in faulty capacitors at the capacitor manufacturing or handling plant (iii) contaminated rags, sawdust, Fuller's Earth etc, arising at manufacturing and handling plants. ; 2 9 , Non of these can be disposed of at present-by high-temperaturo incineration. Thio is not a problem in the caso of (iii), since the quantities are ve*"' u and NEV 036310 landfill is an adequate disposal method. For (ii), the problem is a diminishing one, since PCB-containing small capacitors aro 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 (i), still-bottom residues, represent a low volume, high-hazard waste requiring.destructive disposal for which no adequate technology exists at present* certain IjO. The cost of research into/alternative methods of disposal for still-bottom residues is likely to be considerable, perhaps 5 0 t000-1 00 ,0 0 0 . 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 tho 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 creato process technology problems. It io not yet possible to set a time -these particular ,, scnlo on the development of/altornative technologies. However, the hearth-type kiln being developed by He-ChemLtdio being investigated for its ability to-destroy the. PCB content of contaminated solids* and at present, this'approach appears to be very promising. RECOMMENDATIONS In view of the evidence now available concerning the action and distribution of PCBs, wo recommend that their use and disposal should be subject to special considera tion. Use ^2. Wo 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 agroomont. However, we regard it as necessary that import of both bulk PCBs and PCB-containing products from non-OECD countries should bo subject to control by licence. ^3 At present, it is not profitable to recover and re-use PCBs from some applica tions, but the situation may change. Those rccoverod PCBs fall outside tho scope of the present voluntary scheme. In addition, another manufacturer could at any timo commence manufacture of PCBs. Whilst in both these cases, subsequent uses should be covered by the OECD agreement, they-would not be covered by tho present manufacturer's rather more restrictive voluntary scheme. We therefore recommend that the present arrangements should continue but bo kept under review.- Ngy 036311 Disposal - llnuifls Vi* A method of disposal of liquid PCBs that is known to bo safe is high-temperature incineration and .we therefore recommend obligatory disposal of liquid PCBs by this method* Thio 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 bo provided for analysis of otack gases to be carried out at frequent intervals* A realistic figuro 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 * 5 kg/day for each site. 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 Committoe 10) on which tho 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* *5 Purchasers of transformers and large capacitors are Informed of the need for adequate disposal and each piece of equipment now Gold carries a label, to this effect. We think that this system will prove effective when Buch equipment becomes obsolete* However, there is a potential problem associated with disposal of unlabelled first-generation equipment. Some retrospective labelling is being carried out; w q 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 tho retrospective labelling exercise as all that can practically be achieved* However.*-wo regard as desirable the compilation of a register of transformers in the UK .. which contain PCBs, since this will aid in future identification* Disposal - solids NEV 036312 t6* The most difficult disposal-problem for tho solid PCB wastes arise with the stillbottom residues* Those must not be disposed of by methods which are not destructive, eg landfillv but cannot yet be successfully incinerated, although tho indications are that an adequate 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 nn adequate technological disposal method is developed. Storage sites and facilities should be registered and licenced for this cpecific purpose, and tho site conditions with regard to monitoring and supervision should bo specified. This recommendation may be taken as a general principle for any hazardous low volume vasto for which no ij f / * y adequate diopoeal technology exists: namely that It is preferablo to store safely $ f and eocuroly until adequato methods of disposal are developed than to disperse the waste in an uncontrolled way ^7 Tho other two categories of PCB-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 used, we consider it acceptable that they should be dispoeod 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 themselves arise (as distinct from equipment using capacitors), eg as: t faulty units at manufacturing plants, we had hoped that their PCB content would have bcon destroyed during disposal by presently-available incineration equipment. However, this method for solids is not yet satisfactorily developed, but the alternative hearth kiln may prove satisfactory If this proves to be the case, we recommend that these capacitors be 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 secure placo until tho method is adequately developed. Such sites would require licensing for this specific purpose. Transportation *t8^ 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 Committco 1 5 * Working Group 0/ Z of the Conference Internationale des Grandes Reseaux Kleetriques a Haute Tension (CIGRS); this would form the basis for an internationally acceptable procedure. Analogous substances **9 * Substances ouch as alkylated chlorobiphenyls and polychlorinated tcrphenyls (PCTs) are otructurally similar to PCBs and have comparable properties. They have, as yet, only Yory restricted uses in the UK and are not manufactured here. They NEV 036313 ' <! do not corao within the tcrmc of the OECD agreement on rCDs and thero ore no controls over their import Wo feci that, in particular, these substances should be subject to the same constraints in use and dinposal as we recommend for PCBs, but positive proposals will dopend on whether their use expands Wo recommend that they be kept undor review (Signed) I Prostt (Chairman) D Paviee M Stansfield H A Vodden R X* Stanley G Davies . J Bentley J P Giltrow (Secretary) A' NEV 036314