Document N2oJwDw05Vm1QmO7a9OOZeM3D

POLYCHLORINATED BIPHENYIS A PERSPECTIVE John +1. Cr a d d o c k , PhD Mo n s a n t o Co m p a n y ! / PCB's (p o l y c h l o r i n a t e d b i p h e n y l s ) have r e c e i v e d c o n s i d e r a b l e a t t e n t i o n OVER THE PAST DECADE BECAUSE OF INCREASING CONCERNS OVER THEIR POSSIBLE EFFECTS ON THE ENVIRONMENT AND HUMAN HEALTH, THESE CONCERNS HAVE PROMPTED A SEARCH FOR ANSWERS TO MANY QUESTIONS WHICH HAVE BEEN RAISED, INCLUDING HOW THEIR EFFECTS CAN BE CONTROLLED, This p r e s e n t a t i o n w i l l b r o a d l y d i s c u s s the m o r e s i g n i f i c a n t PCB c o n cerns AND ISSUES IN THE UNITED STATES, HOPEFULLY, IT WILL PUT PCB'S INTO PERSPECTIVE SO THAT YOU AS INDIVIDUALS CAN MAKE YOUR OWN INFORMED JUDGEMENTS ON THESE ISSUES, Ch e m i s t r y a n d St r u c t u r e F i r s t , w h a t are PCB's ? The t e r m p o l y c h l o r i n a t e d b i p h e n y l s , or PCB's, r e f e r s to a cl a s s of o r g a n i c c h e m i c a l s i n t r o d u c e d into Un i t e d St a t e s i n d u s t r y in 1929, Ch e m i c a l l y , th e c o m p o u n d s ar e m a d e up of c a r b o n , h y d r o g e n a n d c h l o r i n e a t o m s , Th e s e a r e e s s e n t i a l l y a r r a n g e d as 2-6 MEMBERED CARBON RINGS JOINED TOGETHER THROUGH 1 CARBON ATOM ON EACH RING, I.E., A SUBSTITUTED BIPHENYL MOLECULE. In THE BIPHENYL MOLECULE EACH REMAINING CARBON ATOM HAS ATTACHED TO IT ONE HYDROGEN ATOM. WHEN THESE H ATOMS ARE CHEMICALLY REACTED WITH CHLORINE TO SUBSTITUTE A Cl ATOM FOR A H ATOM, PCB'SRESULT, _ Th u s , th e ib p h e n y l ri ng is oc m p o s e d o f : 735412 1/30/81 Q ttf 2 o oO On ^ Page 2 (A) 2-6 MEMBERED RINGS OF CARBON ATOMS, (b ) The tw o ri n g s /Jre j o i n e d t h r o u g h on e c a r b o n a t o m on e a c h r i n g , (c) The r e m a i n i n g 10 c a r b o n a t o m s ha ve a t t a c h e d to e a c h a h y d r o g e n ATOM CAPABLE OF UNDERGOING A CHEMICAL SUBSTITUTION REACTION BY CHLORINE, Be c a u s e of t h e p o s s i b l e v a r i a t i o n s t h a t can o c c u r in s u b s t i t u t i o n of THESE 10 AVAILABLE H ATOMS BY Cl ATOMS., I.E., COMBINATIONS AND PER MUTATIONS, IT IS THEORETICALLY POSSIBLE TO FORM 209 DIFFERENT CHLOROBIPHENYL MOLECULES, Co m m e r c i a l l y p r o d u c e d PCB's c o n s i s t e d of m i x t u r e s of t h e s e 209 p o s s i b l e \INDIVIDUAL PCB MOLECULES; HOWEVER, ONLY ABOUT OF THE THEORETICALLY POSSIBLE 209 ISOMERS ARE FORMED DURING COMMERCIAL PCB MANUFACTURE, Co m m e r c i a l PCB m i x t u r e s c o n t a i n e d f r o m 21%-60% c h l o r i n e (an a v e r a g e o f 3-5 CHLORINE ATOMS PER MOLECULE). Co m m e r c i a l PCB m i x t u r e s t y p i c a l l y c o u l d c o n t a i n v a r i o u s c o n t a m i n a n t s DEPENDING UPON THE PARTICULAR PROCESS USED FOR MANUFACTURE. THESE IMPURITIES INCLUDED VARIOUS POLYCHLORINATED DIBENZOFURANS (PCDF's) AND CHLORINATED NAPHTHALENES, WHICH HAVE BEEN IMPLICATED AS BEING AT LEAST PARTLY RESPONSIBLE FOR SOME OF THE TOXICITY REPORTED FOR PCB'S. I'LL HAVE MORE TO SAY ABOUT THESE IMPURITIES LATER. Pr o p e r t i e s and Uses The c h e m i c a l a n d p h y s i c a l p r o p e r t i e s of PCB's are v e r y u n i q u e a n d it is t h ese unique properties t h a t have led to its w i d e s p r e a d u s e . 735413 0 tfl 2"d; Page 3 PCB'S ARE CHEMICALLY INERT; STABLE AND FIRE RESISTANT, THEY HAVE A VERY LOW VAPOR PRESSURE (BP RANGES 275-4250C), THESE COMPOUNDS FUNC TION UNIQUELY AS DIELECTRIC INSULATORS TO ACT AS NON-CONDUCTORS OF DIRECT ELECTRIC CURRENT, THESE PARTICULAR PROPERTIES MADE THEM IDEALLY SUITED FOR ELECTRICAL APPLICATIONS WHERE HIGH-VOLTAGE ARCING COULD OCCUR; AND RESULT IN FIRES AND/OR EXPLOSIONS; DAMAGE TO EQUIPMENT AND CREATE SIGNIFICANT HAZARDS TO HEALTH AND LIFE. AS THE UNIQUE PROPERTIES OF THIS MATERIAL BECAME MORE FULLY UNDERSTOOD; MANY ADDITIONAL USES WERE FOUND. THEIR FIRE-RESISTANT NATURE MADE THEM AN EXCELLENT CHOICE FOR USE IN HYDRAULIC AND HEAT TRANSFER f l u i d s , The ir i n ert ne ss i m p a r t e d l o n g -l a s t i n g q u a l i t i e s to l u b r i c a n t s . They also improved the wa ter p r o o f i n g characteristics of surface c o a t ings AND OFFERED SIMILAR AND OTHER BENEFITS TO THE MANUFACTURERS OF CARBONLESS COPY PAPER; PRINTING INKS; PLASTICIZERS AND SPECIAL ADHESIVES. Distribution Ov e r four d e c a d e s ;-PCB's e v o l v e d as a t r u l y un i q u e cl a s s of c h e m i c a l s WHICH MET BOTH IMPORTANT SOCIETAL AND INDUSTRY NEEDS, It WAS WITHIN THIS FRAMEWORK THAT MONSANTO AND OTHER PRODUCERS DEVELOPED A GROWING; WORLDWIDE BUSINESS FOR THESE VERSATILE PRODUCTS, FROM 1930 TO 1977; WHEN PCB MANUFACTURE CEASED IN THE U.S.; ABOUT 1.4 BILLION POUNDS OF PCB'S WERE PRODUCED, It IS ESTIMATED BY VARIOUS SOURCES THAT OVER HALF OF THOSE ARE STILL IN USE TODAY IN ELECTRICAL TRANSFORMERS AND CAPACITORS. 735414 GENP 000638 Page 4 A 1979 r e p o r t by The Na t i o n a l Ac a d e m y of Sc i e n c e s Listed Mo n s a n t o In d u s t r i a l Ch e m i c a l s Co m p a n y as h i s t o r i c a l l y the o n l y i m p o r t a n t U.S. PRODUCER OF PCB'S. MONSANTO'S PLANTS WERE LOCATED AT ANNISTON, Al a b a m a ., an d Sa u g e t , Il l i n o i s , w h e r e p r o d u c t i o n of PCB's e n d e d in 1970 and 1977, r e s p e c t i v e l y , PCB's HAVE ALSO BEEN PRODUCED, IMPORTED OR EXPORTED BY A NUMBER OF OTHER COUNTRIES. OTHER PRODUCING COUNTRIES WERE ITALY, FRANCE, JAPAN, Gr e a t Br i t a i n , Au s t r i a , Cz e c h o s l o v a k i a , West Ge r m a n y , Spa in an d t h e U.S.S.R, Ac c o r d i n g to th e U.S, En v i r o n m e n t a l Pr o t e c t i o n Ag e n c y , PCB's w e r e IMPORTED FOR USE BY FINLAND, NEW ZEALAND, CANADA, FRANCE, ITALY, No r w a y , Sw e d e n a n d Gr e a t Br i t a i n , Co u n t r i e s w h i c h ha ve e x p o r t e d PCB's include Fr a n c e , It a l y a n d Great Br i t a i n . Ma n y Eu r o p e a n c o u n t r i e s s t i l l a l l o w , a n d in some c a s e s , r e q u i r e use OF PCB EQUIPMENT FOR CERTAIN APPLICATIONS. THESE REQUIREMENTS ARE BASED UPON THEIR OWN RISK/BENEFIT ASSESSMENTS OF THESE COMPOUNDS. Risk/Benefit The r i s k /b e n e f i t issue w i t h r e s p e c t to PCB's is t h e ke y to the w h o l e PCB p r o b l e m . Much s o u l -s e a r c h i n g is b e i n g do ne to d e f i n e t h e s e PARAMETERS FOR PCB'S, THE B E NEFIT SIDE OF THE EQUATION IS PERHAPS THE EASIER OF THE TWO TO DEFINE. GENP 000639 735415 - WE KNOW THE BENEFITS OF USING NON-FLAMMABLE PCB'S IN CERTAIN KEY AND ESSENTIAL INDUSTRIES WHERE TECHNICALLY SUITABLE REPLACEMENTS ARE NOT READILY AVAILABLE, We CAN CALCULATE THE BENEFIT OF PREVENTING FIRES AND SAVING LIVES IN: HIGH-RISE BUILDINGS, HOSPITALS, SCHOOLS * UNDERGROUND UTILITY TUNNELS UNDERGROUND TRANSPORTATION FACILITIES, E.G., SUBWAYS, TRAINS, RIVER TUNNELS, PARKING GARAGES HYDRAULIC SYSTEMS OF AIRPLANES AND OTHER PUBLIC TRANSPORTATION UTILITY POWER TRANSMISSION AND DISTRIBUTION CENTERS HOW DO WE QUANTITATIVELY MEASURE RISK -- RISK OF HUMAN HEALTH HAZARD RISK OF ENVIRONMENTAL DAMAGE, ETC,, An d , compare th em with b e n e f i t s ? 1 This r i s k /b e n e f i t p r o b l e m is n o t u n i q u e to PCB's, b u t c o n f r o n t s us WITH MANY CHEMICALS AND MANY ASPECTS OF LIFE, WHETHER IT'S A NEW m e d i c a l /s u r g i c a l p r o c e d u r e , a ne w (or o l d ) c h e m i c a l , a n e w t o y or AUTOMOBILE OR A NEW GADGET OR WORK-SAVING APPLIANCE, ENVIRONMENTAL AMD HEALTH CONCERNS In THE LATE 1960'S, SOME AO YEARS AFTER PCB'S WERE INTRODUCED, THE FIRST SIGNS OF POTENTIAL ENVIRONMENTAL PROBLEMS TURNED UP IN TWO SEPARATE EVENTS -- ONE IN JAPAN, THE OTHER IN SWEDEN. 735416 Page 6 ; Sw e d i s h F indings The f i r s t s i g n of t r o u b l e w a s r e p o r t e d b y a Sw e d i s h b i o l o g i s t , Wh i le USING A NEW AND THEN TOTALLY UNIQUE TECHNIQUE, CHLORINATED PESTICIDE ANALYSIS/ HE FOR THE FIRST TIME IDENTIFIED PCB'S IN THE-BODIES OF FISH. Mo n s a n t o a n d o t h e r s b e g a n i m m e d i a t e l y to st u d y t h e Sw e d i s h w o r k , Bu t , BEFORE THESE FINDINGS COULD BE CONFIRMED OR DUPLICATED IN THE U.S., ANALYTICAL METHODS HAD TO BE REFINED IN ORDER TO SEPARATE PCB'S FROM THE OTHER CHLORINATED HYDROCARBONS (LIKE DDT) THAT WERE KNOWN TO BE PRESENT IN THE ENVIRONMENT, NEW TECHNIQUES ALSO HAD TO BE DEVELOPED TO ENABLE RESEARCHERS TO IDENTIFY THE CHEMICALS IN THE LOW PARTS PER BILLION RANGES BEING REPORTED. Yu s h o In c i d e n t I n 1968, a b o u t 1,000 p e o p l e in Ja p a n b e c a m e ill f r o m ea tin g r i c e o i l h e a v i l y c o n t a m i n a t e d w i t h Ja p a n e s e p r o d u c e d PCB's as a r e s u l t of an UNFORTUNATE INDUSTRIAL ACCIDENT, THIS HAS COME TO BE KNOWN AS THE "Yus ho In c i d e n t ." The l e v e l of PCB c o n t a m i n a t i o n in the r i c e o i l was 2,000-3,000 parts per m i l l i o n , e x t r e m e l y high c o n c e n t r a t i o n s . (For c o m p a r i s o n , l e v e l s b e i n g r e p o r t e d t o d a y in fish a n d w i l d l i f e ar e in THE LOW PPM AND PPB RANGE.) (PPB EXAMPLE) Some news a c c o u n t s l i n k e d th is i n c i d e n t w i t h d e a t h s , s t i l l b i r t h s a n d m i s c a r r i a g e s , w h i l e , in f a c t , no s u c h c a s e s w e r e a c t u a l l y a t t r i b u t e d TO THE INCIDENT. PERSONS EXPOSED TO PCB CONTAMINATED RICE OIL DID EXPERIENCE DIZZINESS, NAUSEA, LOSS OF APPETITE,WEAKNESS AND DERMATOLOGICAL SIDE EFEECTS, INFANTS, BORN TO MOTHERS WHO HAD BEEN EXPOSED DURING PREGNANCY, EXHIBITED DARKENED SKIN AT BIRTH; HOWEVER, IN EVERY CASE, THIS CONDITION CLEARED WITHIN THREE WEEKS. 735417 ENP 000641 Page 7 The v i c t i m s of th e Yu s h o In c i d e n t ha v e b e e n s u b j e c t e d to e x t e n s i v e FOLLOW-UP MEDICAL STUDIES SINCE THE EVENT TO EVALUATE POSSIBLE LONG TERM CHRONIC EFFECTS OF THE EXPOSURE, SOME LONG-TERM CHRONIC HEALTH EFFECTS WERE OBSERVED IN THE YUSHO PATIENTS, INCLUDING CANCER, HOWEVER, RESULTS OF THESE INVESTIGATIONS INDICATE THAT PCB'S PER SE MAY 01 HAVE BEEN THE CULPRIT IN THE YUSHO INCIDENT, OTHER ORGANIC CONTAMINANTS KNOWN TO BE SIGNIFICANTLY MORE TOXIC THAN PCB'S HAVE BEEN FOUND IN PATIENTS AT HIGH CONCENTRATIONS AND IN JAPANESE MANUFACTURED PCB'S. So m e m e d i c a l r e s e a r c h e r s a n d s c i e n t i s t s ar e no w u n w i l l i n g to b l a m e PCB'S FOR CHRONIC EFFECTS OBSERVED IN THE YUSHO INCIDENT, ESPECIALLY IN LIGHT OF SEVERAL HUMAN EPIDEMIOLOGY STUDIES NOW AVAILABLE RELATED TO PCB EXPOSURE. Although conclusions about that incident have been clouded by the UNKNOWN IMPACT OF IMPURITIES IN JAPANESE MADE PCB'S, THE INCIDENT SOUNDED A CAUTIONARY SIGNAL. U.S, Con cerns I n 1970, WHEN THESE SCIENTIFIC INVESTIGATIONS FIRST CONFIRMED THE PRESENCE OF PCB'S IN THE ENVIRONMENT IN.THE U.S, AND LONG BEFORE INFORMATION REGARDING THE POTENTIAL IMPACT OF THIS CONTAMINATION WAS DETERMINED, MONSANTO, WORKING WITH VARIOUS AFFECTED INDUSTRY SEG MENTS AND GOVERNMENT AGENCIES, VOLUNTARILY BEGAN ITS PROGRAM OF TERMINATING SALES OF PCB'S FOR OPEN APPLICATIONS -- THOSE WHICH COULD LIKELY RESULT IN UNCONTROLLABLE ENTRY INTO THE ENVIRONMENT, Ho w e v e r , t e r m i n a t i o n of sa l e s for d i e l e c t r i c uses w o u l d h a v e r e s u l t e d IN SEVERE ECONOMIC AND SOCIAL PROBLEMS FOR THE NATION. THIS WAS RECOGNIZED BY THE FEDERAL INTERDEPARTMENTAL TASK FORCE ON PCB'S WHICH CONCLUDED IN 1972 THAT: 773355441188 o 2 OooofSe. --Si- Page 8 "Th e i r c o n t i n u e d us e for t r a n s f o r m e r s a n d c a p a c i t o r s in t h e n e a r FUTURE IS CONSIDERED NECESSARY BECAUSE OF THE SIGNIFICANTLY INCREASED RISK OF FIRE AND EXPLOSION AND THE DISRUPTION OF ELECTRICAL SERVICE WHICH WOULD RESULT FROM A BAN ON PCB USE." At t h i s t i m e , Mo n s a n t o m a d e th e c o n s c i o u s d e c i s i o n to c o n t i n u e s u p p l y ing PCB's o n l y to t h e e l e c t r i c a l p o w e r d i s t r i b u t i o n i n d u s t r y w h e r e t h e y WERE MARKETED AS DIELECTRIC FLUIDS IN "CLOSED" OR SEALED SYSTEMS SUCH AS TRANSFORMERS AND CAPACITORS. In CONTINUING THESE SALES, MONSANTO REQUIRED CUSTOMER ASSURANCES THAT THE MATERIALS WOULD BE SAFELY HANDLED AND PROPERLY DISPOSED. Mo n s a n t o , t h e g o v e r n m e n t a n d t h e e l e c t r i c a l in d u s t r y together concluded THAT THE BENEFITS TO SOCIETY OF CONTINUED PCB DIELECTRIC USE IN ENCLOSED ELECTRICAL UNITS FAR OUTWEIGHED THE RISKS. THE KEY TO MANAG ING THE RISK WAS SOUND MAINTENANCE PRACTICE AND DISPOSAL CONTROL. I n 1977, Mon s a n t o v o l u n t a r i l y c e a s e d a l l p r o d u c t i o n of PCB's o n c e we HAD BEEN ASSURED BY THE ELECTRICAL POWER INDUSTRY THAT SUITABLE SUBSTITUTES WERE AVAILABLE. ENVIRONMENTAL EFFECTS PCB's ARE s t a b l e ; t h e y r e s i s t d e g r a d a t i o n in t h e e n v i r o n m e n t a n d PERSIST FOR LONG PERIODS OF TIME. As THEY PERSIST, THEY TEND TO ACCUMULATE IN ANIMALS AS THEY MOVE UP THE FOOD CHAIN. LOWER ANIMAL FORMS CONSUME THEM.AND IN TURN ARE CONSUMED BY HIGHER FORMS AND, IN SOME CASES, PCB'S MAY ULTIMATELY REACH HUMANS VIA THE FOOD CHAIN. 735419 0 w 1 Oooon Page 9 The im pac t of PCB c o n t a m i n a t i o n on e c o l o g i c a l s y s t e m s is n o t f u l l y UNDERSTOOD. * HOWEVER, THERE- HAVE BEEN A NUMBER OF ATTEMPTS TO SUM MARIZE APPARENT EFFECTS AND TO ESTIMATE POSSIBLE FUTURE IMPACTS. PCB'S HAVE BECOME WIDESPREAD THROUGH CERTAIN NATURAL ANl3 MAN-MADE MECHANISMS AND ARE OFTEN FOUND AT VARIOUS LEVELS AND LOCATIONS IN THE SOIL, AIR AND WATER. PCB CONTAMINATION IN URBAN AIR HAS BEEN REPORTED. ALSO, SOME U.S. WATERS AND SEDIMENTS SHOW PCB CONTAMINATION. PCB'S ARE FOUND AT VARIOUS LEVELS IN ANIMAL AND AQUATIC SPECIES. ONE STUDY CONDUCTED BETWEEN 1970 AND 1974 BY THE U.S. FlSH AND WILDLIFE Co m m i s s i o n s h o w e d PCB r e s i d u e s in v a r i o u s f r e s h w a t e r f i s h , w a t e r f o w l AND STARLINGS. A 1972-1974 STUDY OF THREE LAKE MICHIGAN FISH SPECIES TAKEN IN THE EASTERN PART OF THE LAKE SHOWED MEAN WHOLE FISH CONCEN TRATIONS RANGING FROM 5,24 TO 22,9'PPM*IN BLOATERS, SALMON AND LAKE TROUT.. More r e c e n t st udi es in the Great La k e s (1979-1980) indicate t h a t PCB LEVELS IN FISH ARE NOW DECREASING. SIMILAR REPORTS HAVE BEEN MADE FOR FISH IN OTHER PARTS OF THE COUNTRY. PCB'S HAVE BEEN FOUND IN THE GENERAL U.S. POPULATION, SAMPLES OF HUMAN ADIPOSE TISSUE AND MILK, COLLECTED IN 1973 AND 1974 IN A NATIONAL SURVEY, SHOWED THAT 35,1% AND 40,3% OF THE SAMPLES, RESPECTIVELY, CONTAINED 1 PPM OR MORE PCB'S ON A WETWEIGHT BASISj ABOUT 5.0% OF EACH STUDY SHOWED GREATER THAN 2 PPM PCB'S, 735420 -- Q t%n oo, Page 10 HEALTH CONCERNS Qu e s t i o n s ha ve b e e n r a i s e d in fo ur a r e a s of p o s s i b l e h e a l t h e f f e c t s of PCB's: (a ) skin (r e d d e n i n g , r a s h e s , c h l o r a c n e ) (b ) s y s t e m i c e f f e c t s (l i v e r d a m a g e , r e s p i r a t o r y e f f e c t s ) (c) WORKER EXPOSURE (d ) c a r c i n o g e n i c i t y I n t h e c l a s s i c a l s h o r t -t e r m e x p o s u r e or a c u t e t o x i c i t y s e n s e , PCB's ARE CLASSIFIED AS "SLIGHTLY TOXIC" BY ORAL INGESTION, LD5Q 8,000-12,000 m g /kg (s i m i l a r to Na Cl -s a l t ). For i n h a l a t i o n , 0SHA has e s t a b l i s h e d SAFE EXPOSURE LEVELS FOR WORKERS EXPOSED TO PCB'S, (HE EIGHT-HOUR TIME-WEIGHTED AVERAGE THRESHOLD LIMIT VALUES (TLV) FOR WORKER EXPOSURE are 1,0 (42% c h l o r i n e ) to 0.5 (54% c h l o r i n e ) m g /m ^.) S -K M Lo n g e r -t e r m s t u d i e s on s k i n e f f e c t s u s i n g l a b o r a t o r y a n i m a l s have SHOWN THE FOLLOWING: (a ) Re p e a t e d a n d p r o l o n g e d sk in c o n t a c t w i t h t h e h i g h e r c h l o r i n a t e d BIPHENYLS CAN PRODUCE SKIN IRRITATION. (b ) Ha r m f u l a m o u n t s can be a b s o r b e d u n d e r r e p e a t e d , p r o l o n g e d CONDITIONS, SUCH AS BY WEARING LEATHER GOODS THAT HAVE BECOME SATURATED WITH PCB'S. (C) A SAFE EXPOSURE LEVEL DOES EXIST FOR EACH PCB MATERIAL (I.E ., A NO-EFFECT LEVEL). I n a d d i t i o n , s t u d i e s in 218 human v o l u n t e e r s us i n g th e pa t c h t e s t TECHNIQUE OF THE U.S. PUBLIC HEALTH SERVICE CONCLUDED THAT AROCLOR 735421 G "d 2 -a ooo 05 Page 11 (PCB) "...HAS NO PRIMARY IRRITANT EFFECT NOR IS IT A SENSITIZER OF HIGH POTENCY./.," (MONSANTO RECORDS SHOW THAT THIS STUDY USED Aroclor 1254.) Human exposure studies also indicate th at skin effects are rever si ble ONCE THE SOURCE IS REMOVED, In h a l a t i o n /Re s p i r a t o r y St u d i e s Several an ima l tests have been performed to study the effects of LONG-TERM INHALATION EXPOSURE TO PCB'S. I n SOME CASES IT WAS NECESSARY TO HEAT THE PCB'S IN ORDER TO OBTAIN THE HIGHER CONCENTRATIONS NECESSARY TO CONDUCT THE EXPERIMENTS. Va r i o u s PCB's w e r e s t u d i e d a t t e s t c h a m b e r c o n c e n t r a t i o n s of a b o u t 1-6 PPM. No INJURY WAS OBSERVED AFTER PROLONGED INTERMITTENT EXPOSURE OF SEVERAL ANIMAL SPECIES AT THESE CHAMBER CONCENTRATIONS USING THE LOWER CHLORINATED PCB's (i.E., 42% Cl ) . At COMPARABLE TEST CHAMBER CONCEN TRATIONS OF THE HIGHER CHLORINATED PCB'S (E.G., 54% Cl ) SIGNS OF REVERSIBLE LIVER CELL INJURY WERE APPARENT, Pa r t l y ., a s a r e s u l t of t h e s e s t u d i e s t h e Am e r i c a n Co n g r e s s of Go v e r n m e n t In d u s t r i a l Hy g i e n i s t s (ACGIH) TLV s t a n d a r d s w e r e e s t a b l i s h e d and WERE SUBSEQUENTLY INCORPORATED INTO CURRENT OSHA STANDARDS (1,0 AND 0.5 m g /m ^), 735422 GENP 000646 Page 12 Wo r k e r Ex p o s u r e /Ep i d e m i o l o g y * The h e a l t h e f f e c t s of l o n g -t e r m h u m a n e x p o s u r e to PCB's ha ve b e e n CAREFULLY REVIEWED BY SEVERAL RESEARCH GROUPS, MONSANTO* IS AWARE OF SEVEN EPIDEMIOLOGICAL STUDIES DONE IN THE U.S, OF GROUPS OF PEOPLE e x p o s e d to PCB's. Th e s e in cl u d e d p e r s o n s w i t h o c c u p a t i o n a l , as w e l l AS COMMUNITY, EXPOSURE, THE POTENTIAL HEALTH EFFECTS STUDIES INCLUDED DEVIATIONS IN BIOLOGICAL PARAMETERS (SUCH AS BLOOD AND TISSUE LEVELS) AND REPORTED SYMPTOMS AND ILLNESSES, In ADDITION, THE CAUSES OF ANY DEATHS OF ANY PERSONS FROM THE SAMPLE POPULATION WERE INVESTIGATED. The four most recent studies appear to constitute the most extensive EPIDEMIOLOGICAL WORK YET DONE ON PCB'S. In total, the human epidemiology experience indicates an absence of MORBIDITY (ILL HEALTH) ASSOCIATED WITH SIGNIFICANT EXPOSURE TO PCB's, More i m p o r t a n t l y , no ne of t h e s e s t u d i e s f o und PCB's to c a u s e CANCER IN HUMANS. Po t e n t i a l Ca r c i n o g e n i c i t y - An i m a l St u d i e s What a b o u t c a n c e r in a n i m a l s ? I n 1975/ Dr . Re n ate K imbro ug h r e p o r t e d THE INDUCTION OF LIVER CARCINOMAS IN FEMALE RATS FED AROCLOR 1260, A PCB, FOR TWO YEARS. Mo n s a n t o Co m p a n y ha d s p o n s o r e d p r e v i o u s l y t h r e e 2-y e a r ra t f e e d i n g STUDIES USING THREE DIFFERENT AROCLOR MIXTURES, INCLUDING THE SAME lot of Ar o clo r 1260 u s ed by Dr. Ki m b r o u g h , The RESULTS FROM THE Mo n s a n t o s t u d i e s s h o w e d t h a t t h e t e s t c o m p o u n d s p r o d u c e d l i v e r injur y BUT m CANCER. 735423 1GENP 0 0 0 6 # Page 13 An e x t e n s i v e r e - e v a l u a t i o n b y i n d e p e n d e n t c o n s u l t a n t s w a s m a d e o f t h e INLIVER TISSUE SPECIMENS FROM T H E MONSANTO SPONSORED STUDIES. ADDITION/ SPECIMENS OF LIVER TISSUE FROM Br . KIMBROUGH'S STUDY WERE ALSO EVALUATED BY INDEPENDENT CANCER RESEARCH EXPERTS. THAT REVIEW FAILED TO CONFIRM THE KIMBROUGH FINDINGS. In OTHER WORDS/ IT SHOWED NO OCCURRENCE OF LIVER CANCER IN ANY OF THE FOUR STUDIES. I 1977/n t h e Na t i o n a l Ca n c e r In s t i t u t e r e p o r t e d t h e i r r e s u l t s o f y e t ANOTHER INDEPENDENT STUDY FOR POSSIBLE CARCINOGENICITY OF PCB's (AROCLOR 1254) USING RATS IN A 2~YEAR FEEDING STUDY. THE NCI REPORT STATED THAT AROCLOR 1254 WAS NOT A CARCINOGEN UNDER THE TEST CONDITIONS. SUMMARY/CONCLliSIONS PCB'S HAVE BECOME AN INTENSELY EMOTIONAL ISSUE. IMPORTANT DECISIONS AFFECTING THEIR USE/ STORAGE AND ULTIMATE DISPOSAL ARE BEING MADE WITHOUT BENEFIT OF PROPER SCIENTIFIC ASSESSMENT. PCB'S WERE USED AS THE SYMBOLIC EXAMPLE OF WHY THIS NATION NEEDED TOUGH/ NEW REGULATIONS TO CONTROL TOXIC SUBSTANCES. In THE PROCESS/ THE HAZARDS OF PCB's WERE GREATLY EXAGGERATED! In SOME CASES/ THESE COMPOUNDS HAVE BEEN LABELLED BY REGULATORY A G E N CIES/ LEGISLATIVE BODIES/ THE POPULACE AND THE MEDIA AS HUMAN "CANCER-CAUSING AGENTS" AND "DEADLY TOXINS." HOWEVER/ THE SCIENTIFIC EVIDENCE DOES NOT SUPPORT THESE CLAIMS. 735424 GENP 000648 Page l| Th e r e ha s n e v e r b e e n a s i n g l e d o c u m e n t e d c a s e in t h i s c o u n t r y w h e r e PCB'S HAVE BEEN SHOWN TO CAUSE CANCER OR ANY OTHER SERIOUS HUMAN HEALTH PROBLEMS. I In n o w a y DO WISH t o m i n i m i z e THE VERY REAL e n v i r o n m e n t a l c o n c e r n s ASSOCIATED WITH IRRESPONSIBLE DISPOSAL OF WASTES CONTAINING PCB'S, PCB'S ARE PERSISTENT. THEY BIOACCUMULATE IN LIVING ORGANISMS -- THAT IS,. THEY BUILD UP IN THE FATTY TISSUE, EACH NEW DOSE ADDS TO WHAT IS ALREADY THERE. AS COMPANIES., INDIVIDUALS AND AS A NATION., WE SHOULD MAKE PROPER ASSESSMENTS OF PCB'S AS WELL AS OTHER WASTES AND TAKE STEPS TO SEE THAT PROPER HANDLING, STORAGE AND ULTIMATE DISPOSAL OCCURS. THERE ARE ENOUGH LEGITIMATE CONCERNS ABOUT POTENTIAL ENVIRONMENTAL HARM FROM PCB'S (AND OTHER.CHEMICALS FOR THAT MATTER) WITHOUT USING SCARE-MONGER LABELS SUCH AS "CANCER-CAUSING" AND "DEADLY TOXIN" TO UNNECESSARILY ALARM THE PUBLIC. 735425 GENP