Document zQyEODDpLk5NK7MJ6nGm70VJ3

f-i f M-- -r-pt TJprr i: . r V 3 irtoCj J U SMHOARRVTKTAUOl -mREOPNOORCTEOR Sw /l H POLYCHLORINATED BIPHENYLS AND THEIR USE IN CAPACITORS CQTCf\f\ J iK in r \ G eneral E lectric Company F airfield, Connecticut Septem ber 26, 1975 773936 V I v1 i. > *v . TABLE OF CONTENTS 'INTRODUCTION 1* ADVANTAGES OF USING FC B s IN CAPACITORS The Fam ily of PC B s--Structure and Useful P roperties Advantages of PCBs for Capacitor Design 2 2 6 DESCRIPTION OF THE CAPACITOR INDUSTRY Products: Types and Applications of PC B -im pregnated C a p ac ito rs 10 10 M anufacturing p la n ts, em ploym ent and value of shipm ents 10 ORIGINS AND NATURE OF CONCERN Swedish F ish and C alifornia B irds The Yusho incident T o x ic ity FDA T olerances EPA Lim it a Biodegradation and M etabolism Environm ental Burden Environm ental Unknowns 12 12 13 14 16 18 20 22 26 INDUSTRY ACTION LIMITING ENVIRONMENTAL IM PACT . 30 REFERENCES Appendix 1 Types of PCB-Insulated Capacitors Appendix 2 Com position of D ifferent Liquid Chlorinated Biphenyls n o r r n n jrkT7Tr\ 773937 - 1POLYCHLORINATED BIPHENYLS AND THEIR USE IN CAPACITORS 1. INTRODUCTION Tins paper p resen ts an overview of considerations involved in the use of polychlorinated biphenyls (PCBs) in the electrical industry, with particular |* reference to th eir employment in capacitors. Recently, issu es have been raised with regard to public health and environm ental im pact. These issu es are addressed, and the response of the industry to this challenge is re i viewed, with the aim of providing perspective for the consideration of appropriate control m easures. A capacitor is a device that sto re s elejctrical energy. It con sists of two conductive surfaces or electrodes separated by an insulating m edium such a s a ir , p a p e r, p la s tic film , o r o il. 'When a voltage is applied a c ro s s th e electrodes, electrostatic energy is stored in the insulating medium. The circu its in which capacitors are connected m ay be configured to bring about re g u la riz e d sto ra g e and re le a s e of en eirg y in ways c alcu late d to c o n tro l o r modify the perform ance of the circu its and im prove the operation of associated electrical equipment, incluking power transm ission and distribution system s. In typical industrial capacitors the electrode m aterial is aluminum foil and the insulating m edium (dielectric) is paper tissue and/or plastic Him, im pregnated with a liquid dielectric. F o r the past four decades, the liquid im prgnant of choice has been--and continues to be--polychlorinated biphenyls. 773938 GENP 005287 - 2- 2. ADVANTAGES OF USING PC Bs IN CAPACITORS The Fam ily of P C B s--S tructure and Useful P ro p erties The PCBs are a class of arom atic, chem ically inert, chlorinated hydro carbons. The form s suitable for im pregnating electrical equipment are m obile oily liquids, but the term also em braces som e sticky or solid resin s with a relatively high degree of chlorination. They a re non oxidizing, perm anently therm oplastic, of low volatility and non-corrosive to m etals. They a re not hydrolized by w ater, alkalies o r acids. They will not support combustion when heated alone. T heir excellent electrical properties, fire resistance and inertness have made them useful in many applications (1) (2). PCBs are m anufactured by the chlorination of biphenyl with anhydrous chlorine using iro n filings or fe rric chloride as a cataly st (1). The degree of c h lo rin atio n v a rie d fro m 21% to 68% chlorine by w eight in p ro d u cts m an u factured in the U .S . p rio r to 1970. Polychlorinated biphenyls are derivatives of the hydrocarbon, biphenyl, which has th e c h em ic al fo rm u la C 1_Hl un* F ro m one to te n of th e hydrogen atom s in a m olecule of biphenyl can be replaced by chlorine atom s, and the chem ical identify of the resulting compound depends both on the num ber of chlorine atom s that have been introduced (identifying the "homolog") and on the specific sites in the m olecular stru ctu re at which the substitution has oc (identifying th e " is o m e r M). The base stru ctu re of biphenyl, showing a num bering system commonly u s e d fo r p o sitio n s of su b stitu tio n , is th e following: 773939 G E N I* UU5288 - 3- 5* 6* 23 Thus, the 2 ,4 f iso m er of the dichlor homolog may be diagram m ed as: Cl Cl The following is the com position of the com m ercial grade of PCB (A roclor 1016) used in the U .S . capacitor industry with the principal iso m e rs identified. (See also Appendix 2 for com position of other grades. ) /corrA A 773940 -4- H om olog Number of Chlorine T y p ic al Atoms Substituted F o r Composition, Hydrogen Atoms % (3) Biphenyl M onochlorobiphenyl Dichlo r obiphenyl T ric h lo ro b ip h e n y l 0 1 2 3 L ess than 0.1 1 20 57 T e tr achlo r obiphenyl Pentachlorobiph'enyl Hexachlo r obiphenyl Heptachlo r obiphenyl Octo chior obiphenyl 21 L ess than 0.1 None detected None detected P rin c ip a l Isom ers 2 ,4 '; 2,2' 2 , 2 ', 5*; 2 ,2 ', 2, 2 ', 3'; 3,2, 3 ,2 ',3 '; 2 ,3 ', 2# 2 ', 3 ', 5* 3 ,2 ', 3', 6' 2, 5, 5', 4' C onsidering iso m ers and hom ologs, the term "PCB" could identify any of 210 p o ssib le (or 102 pro b ab le) (4) c h e m ic a ls, each w ith d istin c tiv e p ro p ertie This circum stance has led to considerable confusion and unw arranted gener; tion about the properties and effects of PCBs, P C B s m an u fa ctu red in the U nited S tates a re re g is te re d u n d e r the tra d e nam< A roclor of the M onsanto Chem ical Company. Only four A ro d o rs are today being m anufactured for com m ercial applications. They a re A ro clo r 1221, A ro c lo r 1016, A ro c lo r 1242, and A ro c lo r 1254 (5). Of th e s e , only A ro c lo r 1 773941 GENP 005290 *1 . *j 3 3 3 1 3 1 3 3 3 3 1 j i 1 0 is now used in electrical capacitors. T hese'PC B s are m arketed by the average weight percentage chlorine. The la s t two digits of the product num ber indicate the average percent chlorine, except in the case of A ro c lo r 1016, which has a chlorine w eight content of 41%. The p ro p erties of principal in te re st with reg ard to ele ctrica l applications include the following: . A roclor 1232 1016 1242 1248 1254 1260 1268 E le c tr ic a l P ro p e r tie s (2) (3) D ielectric 25 C 5 .7 5.8 5.8 5.6 5 .0 4 .3 2.5 Constant 100 C 4 .6 4.7 to 4. 9 4 .9 4 .6 4 .3 3-.7- Volume R esistivity O hm -cm at 100 C, D ielectric 500 V olts D. C. Strength q * G reater than Above 500X109 35 KV it it ii ii ii ti ti ii n -- n- - Pow er Facto: 100 C, 1000 Hz L e s s Qian 0.3% II II It II II ... Fluid F la m m a b ility R ating-(4) U nderw riters' Laboratories F la m m a b ility R ating_______ E th e r G aso lin e Ethyl Alcohol K erosene (100 M ineral Oil A ro c lo r 1242 A ro c lo r 1016 F. P. ) 100 90-100 60-70 30-40 10-20 2-3 2-3 773942 T67cnn - 6- Advantages of PCBs for Capacitor Design P rio r to 1930 m ost liquid-filled capacitors w ere m ade with m in eral oil. The subsequent substitution of PCBs for m ineral oil m ade possible significant technical im provem ents in the size, reliability, and life of these capacitors. In addition, designers of equipm ent w ere quick to seize upon the low flam m ability c h ara c te ristic to apply capacitors in ways that m ight have been hazardous with oil-filled units. Size 773943 The single m ost im portant property of a liquid to be used in a capacitor is its d ielectric constant (the ratio of its ability to sto re e le ctro static energy relative to air). The d ielectric constant of cap acito r-g rad e askari (A ro c lo r 1016) is 5. 85 w hile th a t of m in e ra l oil is 2 .2 5 . When c a p a c ito r tis s u e is im p re g n ate d w ith th e se liquids th e d ie le c tric c o n stan t of th e pap< liquid com posite is 6.1 for PCB and 2.9 for m ineral oil. F urtherm ore, because of the relatively close m atch between the dielectric constants of cellulose, (6.6) and PCB (5.85) it is possible to s tre s s PC B -im pregnated paper to 400-500 v o lts /m il., while the stre s s e s that can be applied to com parable p a p e r-m in e ra l oil capacitors are lim ited to 300-350 v o lts/m il The combined effect of these technical advantages of PCBs has been to p e rm it a red u c tio n of c a p a c ito r s iz e s to le s s than 14% of w hat th ey w ere in 1924. In 1965 a new d ie le c tric system consisting of paper--polypropyl< film --P C B was introduced with s tre s s capability up to 900 v o lts/m il. overall. Besides favorable stre ss distributions, the ability of PCB to in crease the dielectric strength of polypropylene is partly responsible for this im provem ent. CTFNP 005292 - 7- R eliability and Life PCBs are therm ally and oxidatively m ore stable than m ineral oils, and discharges, which can occur in capacitors, a re less likely to generate gases from PCBs than from m ineral oils . IThe c h em ical sta b ility of PCB in the presence of capacitor tissue and plastic Elm s and the favorable s tre s s distributions between solid and liquid refe rred to above have made it possible to design low -cost capacitors with a life expectancy of m ore th an 10 y e a rs in lighting applications and m o re than 20 y e a r s in e le c tr ic utility applications, , In each application the E rst-y e a r failure rates are le s s than 0, 2%, T his lev e l of life and re lia b ility h ad not b e e n achieved p rio r to the introduction of PC B s. F u rth erm o re, the relativ e non-flamxnabili1 __ w of PCBs significantly reduces the E re hazard com pared to oil units. The capacitor m anufacturer has been able to "design with" the p roperties of PCBs and obtain significant technical im provem ents along with im proved sa fety . A s a r e s u lt, P C B s have supplanted m in e ra l o ils in m o re than 90% of the power and industrial type capacitors m ade today. P r io r to 1952 the liquid u sed in P C B -im pregnated cap acito rs was A ro clo r 125" (54% chlo rin e); i t was th en re p la c e d by A ro c lo r 1242 (42% c h lo rin e), w hich has b e tte r e le c tric a l p ro p e rtie s ; and, beginning in S eptem ber 1971 A ro c lo r 1016 with im proved environm ental com patibility, was substituted. A lternatives Considered 773944 B ecause of the high cost of PC Bs (now m ore than $4 p er gallon of capacitor grade, com pared to 58 for refined m in eral oil) th ere has been a constant << \(t. - 8. search for a m aterial to replace PCBs ever since th eir introduction. A dditional im petus has been added to th is quest as a re su lt of the discoven th a t PCBs of some kinds have becom e widely d isp ersed in the environment (see Section 4). S everal m a te ria ls which have been the subject of study in th e p a s t a r e d isc u sse d in th e re p o rt of the In te rd e p a rtm e n ta l T ask F o rc e (< M ineral oil is unsuitable because of low power facto r leading to enorm ous penalties in the size of capacitors and the increased demand for critical m a te ria ls, and would introduce a fire h azard . C astor oil has a m oderately good d ielec tric constant but is v ery unstable under A. C. disch arg es and in the presence of w ater derivable from paper d ielectric. Dibutyl sebacate, ' useful in high-frequency p arallel plate capacitors where it constitutes the s d ielectric m ateria l, is also incom patible with the use of paper. Silicone fluids have a low dielectric constant and would generally be subject to the s disadvantages as m in eral oil. In the period since the evaluation given by the Interdepartm ental T ask Fore sev eral m anufacturers have had a degree of success with designs based on d ioctylphthalate as th e d ie le c tric (such as G E 's E conol). in tro d u ced in /1973). D ioctylphthalate (or DOP) cap acito rs fo r g en eral application in the "sm all industrial" category, m atch or exceed the ch aracteristics of PCB capacitors in te rm s of stability with tem perature changes, power facto r, and effect of overvoltage on capacitor life. Within c ertain lim its, the effect on life of overtem perature is also a m atch for PCB designs, but t% allow able c a se te m p e ra tu re m u st be held down to 85 C (w hereas PCB 773945 9- c a p a c ito rs m ay be u se d at 95 C o r h ig h e r, with p ro p e r d eratin g . BOP designs have not found any general application in the higher voltage rating: such as required in electric utility service, in p art because of a propen sit to undergo corona damage at lower voltages than PCB capacitors. T h ere ex ists an in d u stry standard fo r non-FCB cap acito rs, EIA 392-1, which can be m et by the u se of DOP capacitors. Except for certain export applications, custom er acceptance has not been good, due at least in p a rt to concern over the higher flam m ability of DOP, and the unit's possibly different behavior in the presence of fire of external origin. Several of the m ajor chem ical companies are currently offering various , candidate d ielectrics for evaluation by capacitor m anufacturers (in addition to DOP). It is not known at this w riting whether any of these will tu rn out to be p referred over PCBs in term s of capacitor perform ance param eters alone. A ll m u st go through an extensive p e rio d of proof te stin g fo r reliab ili, and be screened in their turn for environm ental effects. Then, if one of these is to come into general use, production arrangem ents m ust be made for the fluid and for the capacitors and some accommodation will have to be achieved on the question of flam m ability. Thus, although m uch has been don and is h ein g done. to. qualify a substitute (or substitutes) fo r PCB, the b e st answ er m ay well consist in resolving the controversy that has arisen over PCBs in a m anner justifying th eir continued long range u se. This po ssib ili' is further addressed in Sections 4 and 5. 773946 << - 10 - 3. DESCRIPTION OF THE CAPACITOR INDUSTRY Products: Types and Applications of PC B -im pregnated Capacitors The principal types of FCB-ixnpregnated capacitors and th eir applications a re d e scrib e d in Appendix 1. Some 80 m illion to 100 m illion such capacitc are m anufactured annually, m ost of them for first-tim e u se. M anufacturing p lan ts, employment and value of shipm ents The National E lectrical M anufacturers A ssociation lists six m anufacturers of pow er c a p a c ito rs, a ll of which u se PCB d ie le c tric sy stem s (6): F ederal Pacific E lectric Company, C ornell-D ibilier E lectronics Division, New Bedford, M assachusetts G eneral E lectric Company, Hudson F alls, New Y ork m M cGraw-Edison Pow er System s Division, Greenwood, South C arolina Sprague E lectric Company, N orth Adams, M assachusetts W estinghouse E lectric C orporation, Bloomington, Indiana In addition to the above, the following com panies m anufacture industrial c a p a c ito rs u tilizin g PC B s (7): Aerovox Industries, In c ., New Bedford, M assachusetts C apacitor Specialists,- Escondido, C alifornia E lectrical U tilities Company, LaSalle, Illinois High E nergy, In c ., M alvern, Pennsylvania Ja rd Company, In c., Bennington, V erm ont 773947 GENP 005296 -11 - PR M allory, In c ., Indianapolis, Indiana U niversal M anufacturing Corporation, B ridgeport, Connecticut York E lectronics, Brooklyn, New York In a ll, th e re a re 14 m a n u fa c tu re rs o p e ra tin g 16 p lan ts in 9 s ta te s . T o ta l d ire c t employm ent in the m anufacture of PCB capacitors is believed to lie in the range of 2, 000 to 5, 000 w o rk ers (8). (This estim ate includes a num ber of tra n sfo rm e r w orkers, but at p resen t th ere a re only two m an u factu rers listed by NEMA as producing PCB tra n s fo rm e rs .} Con sidering related secondary jobs and the fam ilies of w orkers,' there are fro m 13, 000 to 34, 000 people dependent upon the PCB cap acito r in d u stry (8). If, fo r any reason, the en tire PC B -using segm ent of the e le c tric a l industry should move off-shore, the unfavorable im pact on balance of paym ents internationally would be som ew here between $68 m illion and $170 m illion annually (8). The total value of U .S. PCB capacitor shipments has been estim ated as ranging fro m $130 to $160 m illion annually (9), broken down as follows: Power Capacitors Sm all Industrial Capacitors T o ta l $ M illion 50 to 60 80 to 100 130 to 160 dN nn 773948 oO to vo 12 - 4. ORIGINS AND NATURE OF CONCERN Swedish F ish and California B irds Polychlorinated biphenyls (PCBs) w ere first m anufactured com m ercial! in 1929, and found increasing application to a broad spectrum of industr u se s over the ensuing forty y e ars. Beginning in the late nineteen-sixtie and early seventies9 evidence began to'appear that these m aterials had been widely dispersed throughout the environm ent. B ecause they are a m a n -m a d e , r a th e r th an a n a tu ra l fam ily of c h e m ic a ls, c o n ce rn a ro s e ov the im plications of this dispersion. Evaluation of PCBs as possible environm ental pollutants has spawned, since 1970, a rapidly expanding scientific lite ra tu re, with the resu lt that a bibliography published in e a rly 1972 contained 870 e n trie s, m ostly of recen t origin (10). During m ost of the h isto ry of the industrial u se of PC B s, they w ere not generally reg ard ed e ith er as hazardous chem icals or as potential enviror. m en tal contam inants (1). The identification of PC Bs as potential food contam inants was f ir s t re p o rte d in -1966 when they w ere d isco v ered in fisl fro m Sw edish w a te rs (3) but a ttra c te d little g e n e ra l c o n ce rn a t th e tim e (1 The growth in public concern m ay be said to date from the publication in a w est coast new spaper, in F ebruary 1969, of a m ajor feature about "a m enacing new pollutant" found in the San F rancisco Bay a rea. The article was based on m arine life research carried out by D r. Robert R iseb ro u g h of the U n iv e rsity of C a lifo rn ia . The follow ing is N a tu re 1s synopsis of D r. R ise b ro u g h 1s p a p er: 77394g e -* ri / ''7T A/A _Tk I * 3 13 - Polychlorinated biphenyls are widely dispersed in the global ecosystem , and are powerful inducers of hepatic enzym es which degrade estradiol. Together with other chlorinated biocides, such as DDT, they could account fo r a large p a rt of the aberration in calcium m etabolism which has been observed in m any species of birds since th e Second W orld W ar. The Yusho incident Although a serious food poisoning episode attributed to PCBs occurred in Japan in 1968, it was not reported in the Japanese lite ra tu re until July 1969 and rem a in e d g e n erally unknown in th e U nited S tates u n til 1971 (10). M ore than 1, 000 people w ere m ade ill through ingestion of g ro ssly con tam inated rice oil. F o r m any, recovery has been painfully slow. T heir sic k n e s s w as nam ed "Y u sh o ,11 o r " r ic e o il d is e a s e ," and h a s b een fu lly re p o rte d in E nvironm ental H ealth P e rsp e c tiv e s (11).. S trictly speaking, th is episode is not a p ro p e r p a rt of the lite ra tu re on environm ental o c c u rre n c e and consequent human exposure, because the PCBs w ere introduced directly into the food through an in dustrial accident (leaks in a heat exchanger), and did not follow a path through the environm ent. N evertheless, Yusho is im portant in the history of the development of concern about PCBs, con tributing especially to the sentim ent in Japan leading to a ban of PCBs in that country. Without in any way discounting the tragedy of Yusho for those affected, it is n ev erth eless n ece ssa ry to point out certain facts that lim it the relevance of this episode to the problem of evaluating the appropriateness of continued u se of PCBs in the electrical industry. 773950 .G k JN i' w o j y y - 14 - 1. As noted above, Yusho stem m ed from an accident in a food plant. T ran sfo rm ers and capacitors w ere not involved; neither was tran sp o rt through the natural environm ent. 2. The ric e oil was contam inated grossly: 2 p a rts p e r thousand (not p e r m illio n o r p e r billion) (11). 3. T hose m ade se rio u s ly ill consum ed an a v erag e of 30 m illig r a m s / day (4); and although som e w ere re p o rte d to be se rio u sly afflicted two y e a r s la te r , none a p p e a rs to have died (1) (11). 4. The Japanese product figuring in the episode, Kanechlor 400, was c h lo rin a te d to about 48% by w eight (com pared to 41% fo r th e U .S . capacitor grade). T ests on chickens have indicated that it m ay have b een un u su ally toxic co m p ared to A m e ric a n PC B s (1), p o ssib ly due to presence (not confirm ed) in the form ulation of the contam inant chlorin dibenzofuran, which has been identified in several foreign products. (Kanechlor has not been m anufactured since 1972.) T o x ic ity The acute toxicity of com m ercial PCBs in experim ental anim als appears to be low (4) (1). Like the useful properties of PC Bs, the biological properties- also v ary with the p articu lar homologs and iso m ers present. The following, graph, constructed from data in the Interdepartm ental T a s` F orce report, illu stra te s the variation of acute toxicity as a function of d eg ree of chlorination of liquid PCB form ulations (4) 773951 < 15 r fe L ` 773952 GNP 0053U1 - 16 - i T he I*D is the single dose (e x p re ss e d in m illig ra m s p e r k ilo g ra m of the rec ip ie n t's body weight) that will resu lt in the death of half of the te s t population within a stated tim e, usually two w eeks. Thus, a high num ber indicates low o ra l toxicity and a low num ber rep re se n ts high toxicity. The term , "highly toxic" has been rigorously defined by the i EPA in conjunction with the Food and Drug A dm inistration and the D ep artm en t of T ran sp o rta tio n as an LD^q of 50 m g/K g (12). F ro m the figu on page 15, it is apparent th at the of a 42% -chlorinated PCB is approxim ately 8, 650, indicating that it is less toxic than the defined level by a factor of m ore than 170. FDA T olerances U sing anim al te sts sim ilar to that described above, the Food and Drug A d m in istratio n identified a n o -effect lev el of 10 ppm in ra ts and dogs, in tro d u c ed a r b itr a r ily a sa fety fa c to r of 100 to 1, and a rriv e d a t a "no effec level for m an of 2.5 to 3 m icrogram s p er kilogram of body weight. This procedure yields an allowable level of PCB ingestion of approxim ately 0.175 m illig ram s p e r day for a 70-Kg individual (13). This is regarded as a level that "could be exceeded" if a combination of foods containing the m axim um tolerance levels is regularly ingested (14), presum ably with sm all likelihood of harm . 773953 rA A TK.Tdf'V To set a m axim um intake level based on human data, that should never be ex ceed ed , FDA tu rn e d to the Yusho episode fo r in fo rm a tio n . Of the 1, 00 or so Yusho patients, the one showing overt sym ptom s with the le a st in gestion of Kanechlor was chosen for the calculation. This was a 50-Kg - 17 - individual who in g este d 500 m illig ra m s o v er a p e rio d of 50 days. The FDA em ployed a 10 to 1 safety fa c to r to go fro m an effect le v e l in th e m ost sensitive individual to a perm issable no-effect level, allowing an ingestion of 20 m icrogram s p er kilogram of body weight p er day. This is equivalent to 1.4 m g p e r day fo r a 70-Kg m an, based on a total p erio d of exposure of 50 days (equivalent to the Japanese incident) (13). We have comm ented above on the unrepresentative nature of data based on Yusho; however, the FDA had no other place to turn for human data, as th e re is no other reco rd ed instance of human disease attributed to PC B s (4). With refe ren c e to the above calculations of allowable intake, the FDA established the following "tem porary to le ran c es," expressed as p a rts p e r m illion (14): M ilk (fat basis) 2 .5 D airy products (fat basis) 2 .5 P oultry (fat basis) 5 .0 Eggs 0.5 Complete and finished anim al feeds Anim al feed components 0. 2 .2 0 F ish and shellfish (edible portion) 5. 0 Infant and junior food 0.2 Paper food-packaging m aterial 10. 0 rn rc n n /T W 3 0 773954 - 18 - T here appears to be a reasonable relationship betw een the food lim its shown and the allowable ingestion lim its discussed above. F o r example, if a p e rso n 's supply of fish is contam inated to the action lim it of 5 ppm, he could eat 0.28 kilogram s (or 0.6 lb. )--sa y , a norm al serving at one m eal--every day without exceeding the allowable ingestion based on the Yusho overt-sym ptom calculation. He could eat such a serving about once p er week without exceeding the allowable intake extrapolated from anim al studies. An additional level of protection is afforded by the explicit and im plicit safety factors contained in the derivation of allowable ingestion lim its. EFA Lim its It is not known a t th is w riting wKat b a s is the EFA w ill u se fin ally fo r calculating toxic pollutant effluent standards for FC Bs. However, in a d raft Statem ent of B asis and Purpose issued early in 1975, EFA proposed to base its chronic c rite ria on the FDA to leran ces: "Chronic c rite ria are norm ally based.upon bioassays conducted over longer periods, preferably several life cycles, and established at levels that will sustain physiological functions of aquatic organism s, i. e . , reproduction, growth rate, etc. However, the PCB chronic c rite ria are based on bioaccum ulation of F C B 's by aquatic organism s and are established at levels that should protect'hum an consum ers of aquatic organism s from the ingestion of F C B 's in excess of FDA to le ra n c e s ." (15, page 26) ^ * ; < 773955 * - 19 - T hereupon, EPA (Op. C it., p. 30) p ro ceed s to compound two m o re "safety facto rs" on top of those already contained in the FDA derivation. One of these is im plicit, in the choice of what some biologists feel to be an extrem e bio-accum ulation factor, and the other is explicit and i a rb itra ry , i . e . , 2:1. "B ased on a possible accum ulation facto r in freshw ater o rg an ism s of 225, 000 as exhibited by the fathead minnow, a m axim um FOB am b ien t w a te r c o n cen tratio n of 0. 02 u g /1 would be possible without exposing human consum ers to levels in excess of the PCB tolerance of 5 ppm in edible portions of fre s h w a te r fis h and sh e llfish . A ch ro n ic PCB le v e l of 0. 01 u g /1 in fre s h w a te r should provide an additional 2:1 sa fety fa c to r, and is therefore recom m ended for the protection of human consum ers of freshw ater aquatic life. " It is an interesting exercise to follow the sam e logic, but substitute different, although perhaps equally reasonable num bers: In calculating allowable ingestion from anim al data, use an a rb itrary safety factor for n o -e ffe c t of 10 (in stead of 100). U se a b io -accu m u latio n of 3-, 000, as exhibited by-blue gill and largem outh b ass (instead of 225, 000) in a w elldocum ented study of an actu al lake (23). Om it E F A 's proposed 2:1 additional facto r. With these num bers, one a rriv e s at an FDA tolerance of 50 ppm and a m axim um PCB am bient w a te r c o n cen tratio n of 15 u g /1 . The "best" answ er may well reside som ewhere inside this range of 773956 GENP 005305 - 20 1500 to 1. The need for m ore re se a rc h , to take the guess-w ork out of the setting of lim its, is obvious. Biodegradation and M etabolism It is particularly im portant when discussing biodegradation, m etabolism , and environm ental burdens to distinguish between grades of PCB. In an activated sludge te s t perform ed to predict the fate of various com m ercial g rad es in the environm ent, A ro c lo r 1016 (used today by the e n tire U .S . capacitor industry) was found to biodegrade m ore than twice as fast as A ro clo r 1254 (the principal capacitor im prgnant from the m iddle ninetee th ir tie s u n til the e a rly n in eteen fiftie s). It a lso d eg ra d es 15% f a s te r th an A ro c lo r 1242 (used fro m the e a rly fifties u n til late in 1971). The re s u lts of a key te s t a re shown on the accom panying ch art fro m a 1972 M onsanto p resen tatio n (3). The m ore highly chlorinated species have been consistently reported in environm ental resid u es in wildlife (4). R ecent Swedish re s e a rc h support; the thesis that an im portant factor controlling the rate of m etabolism is the num ber of chlorine ^atoms in the m olecule. PC B s containing le ss thaj five chlorines, the study finds, are not found in human fat; the low est ch lo rin ated Compound p r s e n t in significant am ounts is the 2 ,4 , 5 ,2 r, 5' pentachlorobiphenyl (24). com parison of PCB homologs produced in the factory and those found i n a tu re stro n g ly in d ic a te s se le c tiv e rem o v al fro m the environm ent of lowi chlorinated hom ologs (3). 773957 /-'ttktd no^106 Ave % Degradation Rate ( 48hr Cycle) - 21 - [ Sem i-Continuous Activated Sludge Degradation of Polychlorinated Biphenyls A1ro2c5l4or I i. [ 773958 tr GENF 005307 - 22 - T here is as yet insufficient data to lis t the half-life of vario u s grades of PCBs in the natural environm ent, but there is abundant evidence that the substitution of a m ixture that is relatively free of homologs higher than te tr a (i. e . , A e ro clo r 1016) w ill play a significant role in reducing th e u ltim ate environm ental burden and lev els found in the tissu e of w ild life. Environm ental Burden In 1972, N isbet and Sarofim published a study of ra te s and routes of tran sp o rt of PCBs into the environm ent, based on the situation prevailing in 1970 (16), Since that y e a r, m uch has changed. In an affidavit before the EPA la st y e ar (17), a M onsanto spokesm an stated: 9 .. the situation today is drastically different from conditions which existed only three years ago. Today about 40 m illion pounds p er y ear are being carefully used in the United States by le ss than 50 M onsanto custom ers in the m anufacture of sealed e le c tric a l equipm ent. P r io r to 1971, close to 80 m illion pounds w ere u se d by thousands of c u s to m e r s .11 The figure on page 23 is fro m N isbet and Sarofim . The sh arp downward tr in applications other than capacitors and tra n sfo rm e rs has continued to extinction, as p re d ic te d by the a u th o rs. The only re m a in in g ap p licatio n s ij this category stem from possible unauthorized sales of used m aterial and from uncontrolled im ports. These categories are believed to be sm all. The EPA has estim ated that total im ports in 1974 w ere le ss than 200 tons ( 773959 GENP 005308 U S D O M E S T IC S A L E S (103lbs) 23 YEAR -... U.S. domestic sales of FCBs b j category. 773960 GENF 005309 - 24 - With im proved p ro c e sse s and w aste control, the introduction of waste PC B s into the environm ent from m anufacturing activities has slowed to a tr ic k le . It is e stim a te d th at only 0. 014% of the ap p ro x im ately 79, 000 pounds of PCBs used daily by the capacitor industry are discharged to w ater effluent; th is sm all am ount is only 10. 7 pounds p e r day from the com bined to ta l of the 16 p la n ts in the in d u stry (19) and th e re is re a so n to believe that the total discharge from the transform er industry is even le ss. F acilities now being installed, and process changes that are continuing, will still fu rth er reduce this effluent, but already it is at a level that is totally insignificant com pared to the existing burden placed in the environm ent m ainly by the form er open applications. * F ro m published figures on p ast production of PC B s (4), it is possible to estim ate that, since the introduction of PC Bs in the 1930's, U .S . dom esti 5 u sa g e h a s am ounted to 4. 3 x 10 to n s. The e le c tric a l in d u stry u se d 63% of th is to ta l, a lm o st e n tire ly fo r "c lo se d 11 ap p licatio n s (i. e . , fo r se a le d a p p a ra tu s). The re m a in in g 37% went into "open" a p p licatio n s, such a s paints, p lasticizers, specialty inks, e tc ., or for sem i-open applications e as h e a t-tra n sfe r system s and hydraulic system s. A reasonable assumptic is th a t 10% of the e le c tric a l in d u stry u sa g e and 80% of the n o n -e le c tric a l u m ay have leaked into the environm ent. (F or a description of plausible pat se e th e a rtic le by N isb et and S erofim cited a b o v e .) T hus, if one m ak es nc allowance for the destruction of this environm ental input by natural proces such as bacterial degradation and m etabolism , the estim ated total burden c th e U nited S tates b eco m es 1. 5 x 10 to n s. 773961 OENP.0<mi0 - 25 - The following p rem ises and conclusions will be used to calculate the increm ent in this burden resulting from current and projected use of PCBs. 1. F acto ry w aste is being rapidly reduced and is already down to about 2 tons per year. 2. P rocedures for the servicing and rebuilding of tran sfo rm ers a re tight enough virtually to elim inate lo sses to the environm ent from these operations. 3. The disposal of large power capacitors is being managed in such a way, by the utilities which use them , as to.prevent significant d is charge to the environm ent. m 4. The m illions of sm all industrial capacitors used in fluorescent b a llasts, a ir conditioning units, e tc ., probably will never be fully accounted for. However, as m ore and m ore com m unities are adopting im proved waste disposal p ractices, it seem s reasonable to assum e that leakage of PCBs from failed and discarded capacitors will be cut in half in each of the next several decades. 5. The total usage of electrical energy--and consequent employment of PC B tr a n s fo rm e rs and ' c'a p a-c ito rs --w ill not exceed the c la s s ic a l grow th os nN*? ra te of ap p ro x im ately 7% p e r y e a r, i. e . , doubling ev ery te n y e a r s . Growth in use w ill be offset by im proved waste control p ractices, and ( [ the resulting annual contribution to the environm ental burden will rem ain constant and w ill come alm ost entirely from the disposal of failed cap acito rs. T Tr*r r\r\ t . - 26 - The replacem ent capacitor m arket m ay be taken as a m easure of annual fa ilu re s, and the amount of PC B s now going into replacem ent capacitors is e stim ate d as 345 tons p e r y e a r. C apacitors a re so co n stru cted that ap p ro x im ate ly 80% of th e im p r g n an t is a b so rb ed by the so lid p o rtio n s of the d ie le c tric sy ste m , w ith only the rem a in in g 20% fre e to lea k out of a ruptured or eroded capacitor case. If all of this residue should re a c h the environm ent, the annual contribution would be 70 tons. Adding in the two tons fro m our firs t p rem ise , the m axim um in crease in the existing environm ental burden to be expected from the continuation of electrical applications of PCB is therefore 72 tons 150, 000 tons 0.; 00048 That is, less than one one-thousandth of the amount presum ed to be already in the environm ent. Since the fall of 1971, capacitors have been m ade with A roclor 1016, which only ha3 about one-tenth the environm entally p ersisten t higher chlorinated fractions found in the p red ecesso r fluid. A s'the percentage of these newgeneration capacitors among the failed population in creases, the ecological sig n ific a n c e of th e in d u s tria l u sa g e of PC B w ill be* c o rre sp o n d in g ly red u ced Environm ental Unknowns 773963 A com plete a s s e s s m e n t of the environm ental burden includes not only quant: tative analysis of the United States PCB m anufacturing and using industry. nxTD O O S312 - 27 - but an estim ate of other sources of PC B s, a b etter understanding of the fate of PC B s that reach the environm ent, an identification of the degradation products, and b etter data on the biological effects that specific form ulations and th eir m etabolites have upon specific living species in the natural en vironm ent as well as in the laboratory. T here are some other sources of PCB in the environm ent, that have their origin outside the PCB m anufacturing industry. At one tim e, the degradation of DDT/DDE was .suspected as a possible source of PCBs in the environm ent, but we a re not aw are that this hypothesis is being pursued any longer. T here a re som e chem ical m anufacturing operations (e. g ., silicone p ro duction) that produce biphenyl and some chlorinated biphenyl as a w aste byproduct that m ust be incinerated or otherwise destroyed. In textile m ills, the biphenyl used as a dye c a rrie r for synthetic dyes m ay rea ct with chlorine gas used to control odor and effluent ch aracteristics to form polychlorinated biphenyls (20) and it is possible that sim ila r side reactio n s m ay occur in other processes. The im ported PC B s, m entioned previously, while sm all relative to dom estic production, are large relative to the portion calculated to be reaching the environm ent. If it is tru e , as suggested by the EPA, that the 200 tons of im ported m aterial a re going into open applications, they a re m ore significant to the environm ent than the 70 tons possibly reaching the environm ent fro m d iscard ed cap acito rs. The la tte r amount is believed to be situated largely 773964 GENP 005313 - 28 - in contact with soil, where it is relatively im m obile. The im ported m a te ria l p robably co n sists in la rg e p a rt of m a te ria l containing pentachloro homologs and above. Much of this can be kept from the environm ent through existing NPDES perm it routines, but the EPA believes that it I requires additional legislation in o rder to prevent rem aining open applications of the type discontinued by Monsanto and its custom ers. Much of the conflict surrounding the u se of PCBs can be resolved only by continued private and governm ent-supported resea rch .. Industry sources have pointed out that m ost of the alarm s raised about PCBs in the environm ent have originated in determ inations of presence in the en v iro n m en t r a th e r than d e te rm in a tio n s of a c tu a l h amrm : "The extensive harm predicted by some theories has not been found and documented. This lack of evidence indicates that all of the PC Bs do not p e rsist in the environm ent as a resu lt of factors such' a s .. .biodegradation.. One ch aracteristic which undoubtedly is of significant im portance is the ability of P C B s to a d s o r b 1ten acio u sly to p a rtic u la te m a t t e r . . . P r e s e n c e (in the environm ent) should not be assum ed to im ply ad v erse effect; To our knowledge, no published rep o rt ex ists which conclusively rela te s the m ortality of any wildlife species to the p re se n c e of P C B s .. . " (17) 773965 4-,rcrnn J u a n It has been shown, in the preceding analysis, that the input of PCBs to the environm ent is now very sm all relative to past inputs, and it has been pointed out that little evidence exists to indicate that the presen t burden is doing harm . One m ay, how ever, construct a w orst*case scenario that would hypothesize the desirability of trying to clean up what is out th ere. No technology now ex ists that would afford a p rac tic al approach. Dredging of w ater bodies would probably do m ore h a rm than good, as it would re* introduce that portion now believed to be sequestered in soil p articu lates. The in ertn ess of PCBs would appear to rule out chem ical treatm en t. The m ost prom ising possibility seem s to be the augmentation of b acterial degradation. Degradation studies have been carried out on some selected PCB iso m ers with two species of A chrom obacter isolated from sew age, * and the susceptibility of com m ercial polychlorinated biphenyl m ixtures to p rim ary degradation by activated sludge m icroorganism s has been investi; It is possible that the new scientific specialty of m icrobiological genetics have im portant contributions to make in this field. A "long shot" possibility is botanical w ater purification. R ecent work a Max Planck Institute o f Limnology involving the bulrush Scirpus lacu str (or, Schoenoplectus lacu tris Palla) m entions the absorption of pentachl in connection with "su rp risin g possibilities for the utilisatio n of higher p la n ts ." (22) ??3966 - 30 - 4. INDUSTRY ACTION LIMITING ENVIRONMENTAL IMPACT A review of the chronology of significant events in the recognition and control of possible environm ental damage from PCBs illu strates the key ro le played by voluntary, cooperative industry initiatives. The following chronicle lists the m ajo r industry and governm ent actions that followed upon recognition that PC Bs a re widely dispersed in the environm ent and capable of ad v erse effects on various organism s: F e b ru ary 1970 June-A ugust 1970 O ctober 29, 1970 M onsanto, the only m anufacturer of PC B s in the United States, alerted its custom ers to the potential problem of environm ental contamination. M ajor electrical equipment m anufacturers relayed this inform ation to end-use custom ers for electrical apparatus, with advice as to proper destruction of waste PCBs. m H ereto fo re, PCB form ulations had been u sed in a wide variety of applications open to the environm ent, such as p lasticizers for p lastics, coatings, and adhesives; in sem i-open applications, such as hydraulic and heattran sfe r fluids; and in sealed electrical apparatus, nam ely tran sfo rm ers and capacitors (also term ed eondensors). During this period, Monsanto initiated the withdrawal of PCBs from all m arkets except the closed application in tran sfo rm ers and capacitors. The P esticides Regulation Division (then in the Depart m ent of A griculture) issued PR Notice 70-25 to the effect th at " F o rm n la to rs and m a n u fa c tu re rs of eConors poisons containing polychlorinated biphenyls and poly chlorinated terphenyls- should change th e ir forzzxulatioi to elim inate such chem icals either as active o r ina ctv ingredients." c ft 773967 oo u> On - 31 - June 1971 The National Industrial Pollution Control Council (E lectric and N uclear Sub-Council) published "The Use and Disposal of E lectrical Insulating Liquids" and included in th eir rep o rt recom m endations to m inim ize the possibility of entry into the environ m ent of PCBs used in capacitors and tran sfo rm ers. These regulations w ere later developed by a com m ittee of ANSI. A u g u st 1971 Monsanto announced the com m ercial availability of A roclor 1016, a new PCB form ulation to m eet the requirem ents of the capacitor industry. This new m aterial is substantially free of the higher-chlorinated iso m ers that have been found in the environm ent, and has a higher rate of bio-degradation than other com m ercially available PC Bs. The capacitor industry prom ptly completed conversion to the new m aterial. S ep tem b er 1 1971. R epresentatives of several agencies of the F ederal Government established an Interdepartm ental Task F o rce to coordinate the scientific efforts of the Government relative to understanding PCBs and establishing protection from actual or potential hazards. M ay 1972 The Interdepartm ental Task F orce on PC Bs, re p re se n t ing five F ederal Agencies, issued its final rep o rt, "Polychlorinated Biphenyls and the Environm ent. " Among other conclusions, the rep o rt found justification for continued u se of PCBs in tran sfo rm ers and cap acito rs. O ctober 28, 1972 The F ederal W ater Pollution Control Act Amendements of 1972, P L 92-500, becam e law. D ecem ber 18, 1972 The Food and Drug A dm inistration announced (in an environm ental im pact.statem ent) tem porary tolerances for PCBs in food (to becom e p a rt of a new " F a rt 122"). F e b ru a ry 14, 1973 The Organization for Economic Co-operation and Developm ent (OECD) announced a decision of m em b er countries to control the m anufacture and trade of PC B s, stating: "The decision allows for production of PC B s for use in closed system s, such as condensers and tran sfo rm ers in large electrical equipment, which present m inim al risk s for the environm ent." GENP 005317 773968 - 32 - Ju ly 6, 1973 The Food and Drug A dm inistration issued rules lim iting the sources by which PC Bs m ay contaminai anim al feed, food, and food packaging m aterials. T ransform ers and condensers (capacitors) were specifically exempted from the restrictio n s. 1973 A t various dates, se v e ra l m an u factu rers of capacitc introduced a non-PCB dielectric based on dioctyl phthalate, capable of fulfilling a portion of the m ark previously served exclusively by PCBs. D ecem ber 27, 1973 The EPA proposed effluent stan d ard s fo r v ario u s to: pollutants. Proposed standards for PCBs were in cluded. Jan u ary 9, 1974 T he A m e ric an N ational S tandard G uidelines fo r Hand ling and D isposal of C apacitor- and T ran sfo rm erG rade A skar els Containing-Polychlorinated Biphenyl C107.1-(1974) was approved. Ju ly 2, 1975 Culm inating y ears-lo n g effort, EIA announced th achievem ent by the capacitor industry of a daily dis c h arg e le v e l, fro m the 14 com panies and 16 p lan ts com prising the industry, of le ss than 5 Kg, 0. 014 percent of daily usage. GENP 005318 773969 REFERENCES Source of Inform ation Polychlorinated Brphenvls- - Environm ental Im pact: A Review by the Panel on H azardous T race Substances, published in E nvironm ental R esearch. Vol. 5, No. 3, Septem ber 1972. M onsanto A pplication Data Bulletin No. P-115, The A roclors. Monsanto Chem ical Company. P re se n tatio n to the In terd ep artm en tal T ask F o rce P C B sv W ashington, D. C ., May 15, 1972, by M onsanto Company. Interdepartm ental T ask F o rc e, 1972--PC B'3 and the Environm ent. N ational T echnical Inform ation S ervice, Springfield, Va. 22151 Polychlorinated Biphenyls. Environm ental Protection A dm inistration d raft statem ent of basis and purpose, A pril 3, 1975. L etter to D r. C .H . Thompson, EPA , from B ernard H. Falk, P resid en t, National E le ctrica l M anufacturers A ssociation, M arch 25, 1974, In re: P roposed Toxic Pollutant Effluent Standards for A ldrin/D ieldrin, et al, FWFCA (307) Docket No. 1. * P ersonal communication, T yler N ourse, E lectronic Industries A ssociation, W ashington, D. C ., Septem ber 24, 1975. Comments of W estinghouse E lectric Corporation, In re: Proposed Toxic Pollutant Effluent Standards for A ldrin/D ieldrin, et al, FWPCA (307) Docket No. 1, M arch 15, 1974. Unpublished study by G eneral E lectric Company Polychlorobiphenvls (PCBs) and R elated Chlorophenvla: Effects on H ealth and Environm ent, I. Bibliography 1181-1971 ORNL-EIS-72-20, Oak Ridge National L aboratory. M. K uratsune, et al, E pidem ioloeic Study on Yusho. a Poisoning Caused by Ingestion of Rice Oil Contaminated with a C om m ercial Brade of P oly chlorinated Biphenyls, Environm ental Health P erspectives, Experim ental Issue No. 1, A p ril 1972. F e d e ra l R egister, Vol. 38, No. 173, 9-7-73. Supplement to the Final Environm ental Im pact Statem ent. Rule Making on Polychlorinated Biphenyls, FDA, July 2, 1973. 773970 aa jK iu n REFERENCES (Continued) Source of Information F inal Environm ental Im pact Statem ent, Rule Making on Polychlorinate Biphenyls, 12-18-72, Polychlorinated Biphenyls, 3 A pril 1975, issued by EPA as a draft of a proposed Statem ent of B asis and Purpose, E nvironm ental H ealth P e rsp e c tiv e s, E x p erim en tal Issu e No. 1, A p ril 1972. W. B. Papageorge, M onsanto Ind u strial Chem icals C o ., In Re: P roposed Toxic Pollutant Effluent Standards for A ldrin-D ieldrin, et a l - FWPCA (307) - Docket No. 1, M arch 14, 1974. Statem ent by Glenn E . Schw eitzer, D irector, Office of Toxic Substanc Environm ental P rotection Agency, at H earings on PC B s, W isconsin D epartm ent of N atural R esources, August 29, 1975. Statem ent of E lectronic Industries A ssociation to Environm ental P ro tection Agency, June 25, 1975. Gaffney, le tte r to Science, F eb ru ary 1, 1974 Biodegradation of Polychlorinated Biphenyls by Tucker. Saeger, and 'H icks, M onsanto Company (paper accompanying the testim ony of re fe re n c e No. 17) G eneral E lectric Co. Technical Inform ation Report No. EO-75-18, A pril 8, 1975, FC B 's in Suburban W atershed, Reston, Va. by J. M a rte ll et al. E nvironm ental-Scientv k Technology, Septem ber 1975. M. B erlin, J . Gage, S. Holm, The D istribution and M etabolism of Polychlorinated Binhenvs. Departm ent of Environm ental Health, Lund, Sweden, 1974. , 773971 > < A ppendix 1 Types of FCB-Insulated C apacitors (R eprinted from The Role of Polychlorinate Biphenyls in E le ctrica l Equipm ent. G eneral E le ctric Company, Feb. 4, 1972) High-Voltage Pow er G enerally AC capacitors a re used to im prove the power factor of a circu it. Pow er factor is the ratio of tru e power in w atts to the ap p aren t power as obtained by m ultiplying the cu rren t flowing to the load by the circu it voltage. The power factor correction can be made d irectly at the load o r at utility substations. In the la tte r case high ' v o ltage u n its w ill be d esig n ed fo r 4, 800 to 13, 800 volt s e rv ic e . To the utility engineer the use of capacitors is purely a m atter of econom ics. The main benefits that resu lt from the use of capacitors are: 1. Reduction of lo sses associated with the delivery of e lectrical power to the point of use. 2. Reduction of the investm ent required in equipm ent for delivering e le c tric a l pow er to the point of use, which m ay be broken down into: a. Reduction of cu rren t for the sam e kilowatt load. b. Reduction of the kva rating of equipm ent required to handle the sam e kilow att load. c. Reduction of the voltage drop for a given kilow att load. d. C ontrol of delivered voltage if the capacitor kva is varied. .E lectric u tilities also use capacitor banks in se ries w ith d istrib u tion circu its to im prove voltage regulation. High voltage u tility capa c ito rs, low voltage power capacitors, and induction heating capacitors a r e m an u fa c tu re d a t th e -ra te of 200,000 p e r y e a r, about 2 to 3% of which a re for replacem ents; the balance a re for new installations. B. Low Voltage Pow er Capacitors* installed, in in d u stria l plants* a t the dem and s ite (typi cally larg e m otors and w elders) a re designed for 230-to 575-volt se rv ice . C apacitors installed n ear the loads a re the-m ost efficient way to supply the m agnetising c u rren t to produce the flux n ecessary for the operation of inductive devices. Rates for the sale of power are generally stru c tu red to encourage power factor correction at the site, elim inating the Appendix 1 (Continued) need for the e le ctric utility to tran sm it both pow er-producing current and m agnetizing cu rren t all the way from the generator to the plant site. The sam e considerations apply to induction heating applications the principal difference being that capacitors for this rapidly growing application a re designed fo r operation a t 960 to 9600 Hz. C. Lighting C apacitors im prove the efficiency of lighting system s. A fluores cent or m ercury vapor lam p can be ballasted without the use of a capa c ito r. but the power factor of the lighting system would then be in the ran g e of 50 to 60%. F o r c o m m e rc ia l o r in d u s tria l lighting w ith e ith e r fluorescent o r high intensity discharge lam ps, the use of a capacitor in the c irc u it provides p art of the lam p ballasting and brings system pow er fa c to r into the range of 90 to 95%. The c u rre n t m a rk e t for th ese a p p lic a tio n s is about 4 4 ,0 0 0 .0 0 0 u n its annually of w hich about 10% a r e ' estim ated to be replacem ent b allasts. D. A ir Conditioning As in the lighting applicatins, the capacitor im proves system effi ciency. A ir conditioners could be m ade to operate without capacitors, as do home refrig era to rs, but because of the higher capacity required for a ir conditioners, the resu ltan t line c u rren t would virtually elim inate hom e "plug-ins" and would still fu rth er overburden a seriously threatened national power network. A lm ost a ll a ir conditioner pump m otors a re of the split-w inding type on which the capacitor provides phase differential for the so-called s ta rt winding, thus delivering good s ta rtin g to rq u e. The p ro p e r siz e c a p a c ito r p e rm its high (90%) pow er factor after start-u p . The current m arket for this application is about 12, 000, 000 u n its annually, w ith about 5% o f th e s e e s tim a te d to be fo r replacem ent usage. E. Industrial Electronics This m arket .category is a catchall covering many varied applica tio n s, two im portant ones being m otor run and power supply applications. M otor run applications a re for pum ps, fans, and. fa rm feed equipm ent, and do not differ significantly from a ir conditioning applications. The power supply m arket u ses capacitors principally to provide high power factor, but through careful design the capacitor can also provide wave shaping w here desired. The m arket is estim ated a t 23,000,000 units p e r y e a r w ith no estim ate as to the rela tiv e size of the rep lacem en t m arket. 773973 GENP 005322 C om ponents eiven as % Chlorine Biphenyl Mono- chlorobiphenyl Ci- chlorobiphenyl Tri-ichlorobiphenyl T etra-c h lo ro b ip h e n y l Penta-chlorobiphenyl Hex a*,chlorobiphenyl H ep ta-chlorobiphenyl Oc to - c h lo r o b ip h e n y l Com position of D ifferent .Liquid C hlorinated Biphenyla 1221 21 14.8 56.5 26.9 1.42 .06 Monsanto A roclors . 1232 1242' 1016 1248 32 42 41.3+0.5 48 . 02 < 0.1 .72 1.0 ^55 15.6 20 54.5 2.S" 57 .1 -22. Sr 55 6.7* 1.0 < 0.1 4 None det. ' None det. - 1254 54 60 1260 60 70 * Includes higher than penta -chlorinated isom ers, ** No longer in co m m ercial production. ezesoo dMao Source: A ll d ata except 1016, Ref. (4) A ro c lo r 1016 - R ef. (3)