Document 0g750gXEkrwOykvRkkLoNOX0b

DownloadSearchable PDFRandom document
conoco Interoffice Communication To From Oats Subject A. H. Sather J. V. Uptain December 20, 1978 CHEMICAL EXPOSURE MONITORING SUMMARY -FOURTH QUARTER, 1978 RECEIVED JAN 8 1979 MEDICAL DIV I. Spray Metalizing wt * For some time we have utilized a crude "flame coating" process in the main tenance shop for building up metal parts, particularly shafts and similar round objects. The process consists of metering finely divided metal powders, made for the purpose, into a flame, which contacts the metal part to be built up. Some concern developed that workers in the area might, as a result,, be overly exposed to heavy metals, since no controls for limiting the air borne concentration were present. On 10/4/78, eleven (11) air samples were taken, while the various powders were used. The results appear in Table I and clearly show that better controls are needed. Since generation of the fumes is confined to one place in the shop, the most efficient control appears to be an adequately designed, local ventilation/exhaust system. This subject is imder discussion at writing. II. Compound Line I Air Sampling r The final results of the high volume air samples taken on Compound Line I appear in Table II. Although one antimony result (sample 78-102) and one barium result (sample 78-116) are disturbingly high, the most significant problem appears to be lead - especially in view of the new OSHA Lead Stand ard. III. Color Weigh Room p Final analysis results of color weigh room sampling done since connection of the weigh hood to the compound ventilation system appear in Table III. As can be seen, the concentrations of heavy metals are still too high and little, if any, improvement was realized by the hood change. At writing, plans are being cast for re-vamping of the entire operation, including the ventilation equipment. IV. 1978 Lead-in-Air Measurements In anticipation of the questions to be raised as the effective date of the new OSHA Lead Standard approaches, all of the 1978 lead^in-air measurement s made with the high volume technique were summarized (see Table IV). VAB.0001050071 A. H. Sather * December 20, 1978 Chemical Exposure Monitoring Summary Fourth Quarter, 1978 Page 2 A IV. 1978 Lead-in-Air Measurements (Cont.) These measurements were all area-type in nature and, although they are no substitute for the dosimetry specified in the new standard, will be helpful during the "initial determination" that will be required. V. Trimellitic Anhydride n During bag charging of trimellitic anhydride to a plasticizer reactor, one sample was taken. The airborne concentration was found to be 13 milligrams per cubic meter, somewhat i high. More samples are needed to better define the hazard. In the meantime, operators are required to wear respiratory protection during the task, which occurs only during the occasional pro duction of TOTM. VI. Carbon Black Several samples were taken of worker breathing zone air while they were charging carbon into plasticizer reactors. All results were essentially zero, with no significant danger being apparent. VII. Hydroquinone Six air samples were taken in the PVC reactor areas to define airborne concentration of hydroquinone. All results were negative. erald V. Uptain Attachments c: Plant Manager, Department Heads DSC, EDS, DAK, JJH, 0D8 VAB.0001050072 r 00*1 000*SI 001 os) ooz oos oos 1 000*01 001 (So-ID UT *D *V) *8 S OOS 001 001 13d) JTT'I axnsodxg axqssxiu0d 'lueupmnuoa xeqx xoj xpen axnsodxa - 1 r }umixrB}uoD xexnaxjxed jo uojjbj)U93uod d * oaruxjH JO oansodxa aSirajt uoxjBJtqxiBO gpxsino 9X9% sanxBA < xo> XXV in II n. WH :9X9ipi *ud"* + 33 + 13 h ** 'jugagxa sp(i jcoj psAjasqo autx uoTssraia on , 8*I EZ* 88 *E 8S*0 S0* Zl*I 80*Z (sxtnxxw) gxnsodxg quaxeAinbg OOS 00*Z 06 00S*I 001*1 OOZ* I 06S :S31VinDIlWd 1VX0X 89`0 * l 0`8 9S*0 0Z*Z< 80*1 oz*z S8*0 S9* Z9I Z8*0 T*0 *8 si *z I* 0 *6*89> 8*0 > Z*Z 80*1 8S*0 *16`81> 9*0 89*1 06*8 8*0 . 9S*IZ< II*0> S*0 II*Z 11*0 SI *8Z 8*0 6I` I0* SS*0 Z*S 60 * 80*1 08* 9S*Tt* 68*1 8*0 Z*I I*8^ 6*8I 1 88*81 98*1 SS*9 96*901* 96*901* IS*0 IS* I 9'88< i1 S*6 Z* I S6*I Z8*l 8S*0 > S*0 Z*0 9*0 *TV jo X9X9N otqnD xod subx&oxoxh 'U0|)U)iM3U03 aujoqxxv Z*0 8Z*S Z8'0 01*1 6*ZI Z9*86I* SZ*I 08*1 8* S S*I U PB91 9S9ue8ueft rnni^Ba VLOXl l5pTN vnjuo<xiQ ouiz xaddoD mxtxmpBO ^U9U19XH 16 081-8 io)iado eqvn jo g^xsoddo IS 6l-8 IS 16 88 IS8 8I-8 l-8 9SI-84 SEI-84 8/8/0T ONIldHVS VIV aWmOA-HDIH DNIZnVIHH-AVHdS i aiflvi T9A91 93Brf *U01J9JS s,xo^xado 0S8 8I*8 uox)V30l Jutxdues posn odXx xapMOd xaJH 'on oxdees li I*1 VAB.0001050073 '^ M . 00 *T 000`SI 1 001 fc46I UT OS) ooz oos oos 000*01 001 (%XD VLX ad v) 4*PS OOS OOT 001 (IHd) ITT1 sansodxg 9iqss]ud 1 4 1P t 'lusupreiuoa )q) iO| )lTt Mnsodxg l 'quvupniuoa xainojiAad jo uo^w^uaouoD 3 `earux^W t jo aAnsodxa :uaiAjnba W3 wj n n : aaaqM *uq-+ ZD + ID - W3 ** u0 V <H *a>uu uo|}J*qn>3 apfsqno um santA *quanai siq) sjip jcoj paAAasqo aun uotsstma on * 0*0 Z*9 OS *9 P 96* P (AtnxTH) aAnsodxa luaiSApbg 091 006* Z 00P*Z 004 *Z saxvinDixiivd iviox r 11*0 P*0 > 0*0 9P*0 > UU 96*0 ZZ*S 46*1 6Z*Z pB9T * 60*0 84*01 S8*6 69*1 sauaSuew 4P* 0 81*1 S4'0 9P*0 > uniaag 8* P P8*8P P9*91Z 69'ST UOJtl * S8'0 98*9< P9*9IZ< 99*8Spq: +4 IOXOTN SlO 8P*IPI P9*9IZ* SZ`0 61 *Z 0*t 16*0 .9*8Z 1S*1 f0 8Z' 1 SP*0 jcjV 30 zojah ojqrto xad smBXSoxojti 'uot)9j)U93U03 ouxoqajV' * SS*S S1 l*l Pl*PZ zs*o 1 mnxmoxvQ 3UTZ 4 AdddoD mxmp3 luaaata f - i Jtoou doijs /fjo^eaado boa; h ' 93UBU91Q|9H jo OIPP1H ------------ f\ aqjvi jo PIS ojjsoddo uof }uooq 8uf idars auoK ppi-84 ISP PI-84r ZPl-84 0SP 1P1-84 / pasn ad/x Aapnod iajaH 4 *on aidwts* JUvToi 3MI*IdKVS hiv awmoA-roiH ONIZnVlW-AVUdS > (ponufiuoQ) I 918VI * I VAB.0001050074 j l H I h t to 00*1 000*SI 001 oos 003 000*1 (0*D T SV) 3*frS 003 r oos (All) t*A *TFI 3TXO! * . I An Oo * )treupro}uo9 }tn|) jo| qprji unsodxa = l ()tnni|it}uo3 njnoT)nd > jo uo|)U)iu3UQ3 * 3 JI Zl_ n eqi jo oansodxg ^uaivAfnbg W3 :uei{N *113*"+ ZD + 13 * WH ** aguoi uoT^vzqTivs 9pjs?no mbm sntA< ao > nV **uooio *W J0J pOAiesqo oirjt uoissxata on * 8*0 00S* *I*0> 3*0 33* SI T *0 > 1 W0 068 3T*I W0 6fr*3S^ 33'0 > 83*0 000*3 88*0 . 83`S 38*33 *30*0 > WO 1 000*3 *90*0 > Sfr'fr 0'tt 90*0 > 31*0 000*3 1*0 98*3 83*3 A 61*11 6KT 006*11 *WI > 99*S W0T WIt> (OJtUXTW) QjnsodxH auoieAjnbg saivinDiiHVd ivioi UTl osoueSuen pesq *oddo3 T*0 > 03 *VS OS * 93 *l*0 > i jpuia Mat,' * *00x03 as 911*83 33*0> wz 0S*0l 30** * Xinqueg 8 saopuo1i- g uaoMiog SII-^83 33*0 0*0 31*0 WI> S3*0 91*9 09*1 96*31 1*0 > 61*8 WO orii 9 * 03 9fr*8 9S*V3 * 00 aiv jo xeiaH ox quo xad sotoxSojoth * uo|i*x 111001103 1 mw j *00103 MS Xjnqueg 1 saopuoig uooMqog jopuais Mg,, **00103 MS sxdptid|g UddM^dg 801-83 301-83 901-83 xandwoD HniwavD/wniHva -aandNvs dnihh ivdiwhhd 301-83 tHTlTUIOJtlQ an?spe3 anxjeg XUOtBT^UV quzmoxi 4 uoxJvooq SuTtdures 'on airfares 83/8/8 - 83/0/9 DNIlcMVS HIV 3WmOA"H9IH Z HNII ONflOdNOD ii anavx I L i 1 * h k J I ' * VAB.0001050075 -I '00*1 000*ST 001 .oos ooz 000*1 (*0*D T *D V) i'trS OOZ OOS OOS (All) nt*A OTXOI * * )inttpn)uo9 `luaupmiuoo )tq) io; xpnjT axnsodxg jo uox:}.x*ua01103 1 3 `ajuuxxH aqi jo aansodxg luaaiAjnbH . H3 :JOMM iI *113* * *+ zi ZD + n TO H3 'a8uJ uopuqTI113 apxsvio um sani*A < xo> XXV `tuavaxa sxqx xoj paAxasqo 9UTI UOTSSTUIO 0(4 # S0*0 T0*0 9*1 *0*0 (ajnnxiw) axnsodxg xuoxaAfnba 001 *T 90*0 00* 0 *0 06S ZZ*Z 009*1 TT*0> saxvmoiJLHVd tviqi uti 0*0 *0*6 80`0 * wo> *o*o SS*Z 0*0 a T0`0> Z6* T *6*zzz S*Z Z6*0> t 81*0 9S*S ZT *0 TT*0> 1 asauaSutsM paaq jaddoo mtmoaip 0*0 8**0 *0*0> 1*0 *ro *10*0 > 0Z`8T ZS*ZS I'ZT 0Z*T ** * tro > mni xiup^3.1 unxxag Xuovx xuv l> xx\ jo J9J9h 3tqn3 xad sveaSojojH fuox)x)uaouo3 t )uanaiH IITH qsaa Xxnquag 9 xnw jo ja Jiaiuos NS s,aapunodnoo sxapuaxg uaa*uag xauxo3 MS uofxaao'i Sutxdnas a 82T-8Z 9ZI-8Z SZT-8Z 4TT-8Z *on axdnres xaidwoD wmwavD/wniwa ^aidNVS DNiaa TVDiNaro I 8Z/8/8 " 8Z/0/9 ONndwvs hiv awmoA-roiH i ami aNno<woa Cpanat^uoo) II ai8VI ' VAB.0001050076 t4# f 00 *t * 1 000*ST 001 oos ooz 000*1 (0*3 T *3 *V) 2*VS 00 Z OOS OOS (All) )T*T1 otxoi P 4 wr * * 4 4 ' )tnUTK)U03 }B1|1 IO| :nU oxnsodxg - 1 ui 4 )ueuin3U03 jreinoxJ-118^ JO U0])BJUU93U03 * 3 f9Jtn^XTH 9U) xo 9xneHodxg )U0XATnl>H NS ' 9J91(M nn ZD + 13 3 ** * afuu wpjqn optsxno mbm soniA <Jto> nv Sf(() J-O} p9AX9SqO 9UTX UOTSSJUIO ON * 96 *S 006*81 96*2 00V*21 26` 00S*Z 12*9 006*6 9 * I k 001*01 8S*0 001*91 1*0 022 oxnsodxg )U9xAxnba * saivinDiia# vd ivioi *6'0l9 *92*1* *22'0 ** *l*t ** 9S*0 60*0> S0*0 uxx 92*13^ S*80*I ri H*29 68*01** 92*1 ^ 22`0 > 61 *2* 22*0 > *s;2 > 22*102 K7> ' TS*0 > 8*0 2S*0 > 22*0 S*9 60*0> V*0 89*01 0*0> 9S9U8uH pool xoddo3 Z* 6*SS 2*12 6*921 h . 92*1 ^ 61*2 8*8 1*192* I* 91*2 VS*2 > IV2 60*0 > 21*0 16*202 S2*0 > 20*61 S8*6 V9*l 22*0 00*82 * 2V28 VV*22 29*0 62*02 92*2S`2*: 22*61S< S`9T 90* jtv jo <X9*8H otqno Jtod sommSoxoth *U0Tl>l)U3llO3 4 i ntnxnojiiO atniutpBQ untxeg Xuorai)uy )U9U9Xa I 011-82 601-82 SOI-82 V0T-82 TOI-82 86-82 *6.-82 ` on 9xdaws 82/02/2 - 82/22/9 ONIldWVS HIVHWmOA HDIH HOOH HDIHM V0103 hi aiavi + * tmmmm * * T-r t VAB.0001050077 I 4* 00*1 000*SI 1 001 oos ooz 000*1 (0*D ? <*3 V) 4*frS OOZ OOS OOS (All) nI*A *1*11 0^X01 * Itreupn xtioo wu xoj s-msodxg i *luupn)uo3 xvinoxiaod v jo aoxiVJtluaouoD 3 `axnixfH 4 ansodxg XuaivA^nba rn wa EL n n fuD* **+ Z3 + to - a ** * Subj ao|}uq]iti3 9p|S)no jam sonxA ^ ao itV *)U9ai9 xoj poAxasqo 9UXI U0TSSTH9 ON * i- (9XIUXXH) ZO'fr 00*Z SO'I axnsodxg xuaiAfnbg , 004*81 *06*0 000* 4 *8*0 > 066 4*0 saiYinonavd ivxoi UTi *06'O^ *8 *0 > 8t*0 ^ osoub8uh 4S*ZZ *S`944: a 99*841* peaq * 06*0 > 8*0 > 10 *0 > i xoddoo 06*0> 8*0 > 98*0 4S*Z6S 45*4 S*1 ZS * 8S4 S4*I OO'ZT *06*0 > 4Z*8Z SO* IS xxv )o axN 3Tln3 Jdd soRxSoxaxH * uoxTWXua01103 1 nmtdioxiQ nxmp3 tmrtJBg Xuowjxuy luana13 i 811-84 * ZII-84 A nt-84 on 9.xdares 84/0Z/4 - 84/ZZ/9 A DNIldHVS HIV awmOA H9IH HOOd KDIHM H0103 III H18V1 I i t * I * 4 I V I 4 L VAB. OOO1050078 A IMNMW * * I. Sample No. 78-1 78-2 78-3 78-4 78-S 78-6 78-7 78-8 78-9 78-10 78-11 78-12 78-13 78-94 78-98 78-101 78-104 78-105 78-109 78-110 78-111 78-112 78-118 78-102 * 78-106 78-107 78-108 78-115 78-116 78^117 78-125 78-126 78-128 78-17 78-27 78-33 78-46 78-47 78-65 TABLE IV RECAP OF 1978 LEAD IN AIR MEASUREMENTS > 1 " 1 ' 1111 * 11,1 *"" tl111" ...... .. -HIGH VOLUME AIR SAMPLING- Location Concentration, Micrograms per Cubic .Meter of Air Color Weigh Room < 0.5 Color Weigh Room 217.4 Color Weigh Room 390.0 Color Weigh Room 170.4 Color Weigh Room 171.4 Color Weigh Room >327.3 Color Weigh Room 291.9 Color Weigh Room 162.6 Color Weigh Room Color Weigh Room 70.0 i* 575.0 Color Weigh Room 34.8 Color Weigh Room * Color Weigh Room 516.9 26.4 Color Weigh Room ` 10.68 Color Weigh Room 6.53 Color Weigh Room - 0.38 Color Weigh Room 201.27 Golor Weigh Room 47.19 Color Weigh Room 62.14 Color Weigh Room 1 <038.53 Color Weigh Room 9>*178.66 Color Weigh Room Color Weigh Room ^376.54 22.57 Compound Line I - Between Blenders 103.24 Compound Line I - SE Comer, "B" Blender 7.28 Compound Line I - Between Blenders 8 Banbury 34.38 Compound Line I - SW Comer of Mill 22.87 Compound Line I - Between Blenders 6 Banbury^52.49 Compound Line I - SE Comer, "B" Blender 15.77 Compound Line 1 - SW Comer of Mill 5.56 Compound Line I - Between Blenders 6 Banbury m + Compound Line I - Compounder's Desk 272.94 2.55 Compound Line I - SW Comer of Mill 9.04 Compound .Line III - 3' W of SE Comer of Master Batch Charge Platform 1.76 Compound Line III - 3' E of E. Dicer Line 3.66 Compound Line III - SE Comer, FCM Room 45.48 Compound Line III - SE Comer, Feeder Deck 18.31 Compound Line III - E of FCM/Mi11 Conveyor 46.9S Compound Line III - SE Comer, Feeder Deck 198.36 78-140 78-141 78-142 78-143 78-144 Maintenance Shop - Spray Metalizing Maintenance Shop - Spray Metalizing Maintenance Shop - Spray Metalizing Maintenance Shop - Spray Metalizing Maintenance Shop - Middle of Room 1.37 2.29 1.97 S.22 0.96 VAB.0001050079 --------------- 1 ^-----------------------------------------------mi--i n-nnnr-inir-i--nriTiniiTirriiTnmr^^ ------m--i-------- *- - -ita- ' tSf f A c: GGDj, Dept. Heads, DAK-Houston, jf -Ponca * ; AiMmm VAB.0001050080 *$c\ 'T* ' Sample No. 78-66 78-67 78-68 78-76 78-77 78-84 78-86 78-87 78-88 78-89 78-90 78-92 78-93 78-20 78-21 78-25 78-51 78-52 78-73 78-54 78-5S 78-56 78-78 78-79 78-80 78-81 78-91 78-134 78-135 78-136 78-137 78-138 78-139 78-140 78-141 78-142 78-143 78-144 TABLE IV (Continued) Location . Concentration, Micrograms per Cubic Meter of Air Compound Line III- SW Corner, Feeder Deck 20.07 Compound Line III - E. of FCM/Mill Conveyor 46.63 Compound Line III- 3* E of E Dicer Line 3.31 Compound Line III- Mill Oper. Station 0.72 Compound Line III- Mill, Oper. Station 4.46 Compound Line III - Mill, Oper. Station 8.82 Compound Line III- SE Comer, Blender Platform 14.71 Compound Line III - 4* E of Blenders, Floor 6.44 level Compound Line III - 4' E of Blenders, Floor 20.61 level Compound Line III - Blender Platform ^460.46 Compound Line III - Control Room 2.45 Compound Line III - SE Comer, Blender Platform 35.14 Compound Line III - Between Line 3 8 Dry 12.78 Blend Charge Platforms, Floor level. Dry Blend -Mezzanine Above 2nd Floor 27.9 Dry Blend -Mezzanine Above 2nd Floor 2.1 Dry Blend -Mezzanine Above 2nd Floor 3.7 Dry Blend - Mezzanine Between 1st 6 2nd Floor 2.11 Dry Blend - Mezzanine Between 1st 6 2nd Floor 3.73 Dry Blend Mezzanine Between 1st 8 2nd Floors 3.04 Dry Blend - Basement, Blender Platform 4.05 Dry Blend - Basement, Blender Platform 9.03 Dry Blend - Basement Blender Platform 8.10 Dry Blend - Mezzanine Above 2nd Floor 23.15 Dry Blend - Mezzanine Above 2nd Floor 21.79 Dry Blend - Mezzanine Between 1st 8 2nd Floors 35.26 Dry Blend - Mezzanine Between 1st 8 2nd Floors 31.50 Dry Blend - Master Batch Platform, Between 10.35 Hoods Maintenance Shop -Spray Metalizing 5.24 Maintenance Shop -Spray Metalizing 3.19 Maintenance Shop -Spray Metalizing 0.75 Maintenance Shop -Spray Metalizing 1.64 Maintenance Shop -Spray Metalizing 2.23 Maintenance Shop -Spray Metalizing 4.33 Maintenance Shop -Spray Metalizing 1.37 Maintenance Shop -Spray Metalizing 2.29 Maintenance Shop -Spray Metalizing 1.97 Maintenance Shop -Spray Metalizing 5.22 Maintenance Shop - Middle of Room 0.96 VAB.0001050081 'A A M i> wr 1-. * nt <L t * f jtfr V- J*' I <- 1 / tVt rf 1 *' -h, . i VCK Tank Farm 4 1 2 3 4 5 V 6 V7 8 9 10 *MH*iM*m*** Mounted on bottom of D-600 reactor Mcmnted at #3 Recovery System Nmmttd at South unloading station Mounted at respiratory air inlet Mounted at middle unloading station Mounted ar North unloading, station Mounted at Compressor shed Mounted at blowdown tank South end Mounted at North Receiver Mounted at Gear Room (Nest side) 4 A . SK t i. i > var.i VAB.0001050082 |Hih*i .................................................................................................................. .. M .................................................... ............................... .............................................................................................. .. . .............. -tt *- t?t ,(J.P .. i .j : in-, -i ABERDEEN NEW LARGE REACTOR VCM CONTINUOUS MONITORING UNIT TRENDS PERCENTAGE OF SAMPLES WITHIN CONCENTRATION RANGES 12 10 8 fXlu 6 flu o4 lA 2 Q . .Mlb 1 | :J -i-t -l i. f * r h 'p Vh - \ M t' j ; 1 H \\ * F1 '.i'i-i- .!'L j *j A > *. * K 4 - .r < * 'Jb. 8 fib. o6 * O4 2 4 0 12 10 8 Ml CXAui 6 3C I4 tn 2 0 v. Unit down all of May and June. Placed back into service 7/12/78 VAB.OOO 1050083 " r 'i ;j..:3 =irill9SfE!?^!(!r?i'P:S(--M' ^:.:iv^!1i]|;iit-i:l<-sf:i':1, .-. h III! 1 V J: ii- aj!;1 . Il ii I ii<- <*.;::; Ji.isllflir! <!:!i!!:Jls]-.i- =:-r-*: '-'v ;.' * i: 11 j. : .lr '( !;:.r ABERDEEN LABORATORY VCM CONTINUOUS MONITORING UNIT TRENDS -PERCENTAGE OF SAMPLES WITHIN 12 10 8 a. a6 # t& 4 2 0. 8 l0 kn i 1S o4 2 *09 U3SS3 'OLUmM 2Rt| NO IttAia 001 X tHJJNOW AS SUV3A C 3 *7 1 10 S a. 6 i4 tA 2 0 1 Ah A %; <rK. r* it' i $ t' Ji . -m-fe. i- t i i r v hT a ? , J- .r * j?*- % i NttV if t :'- i'r iy? ' '^y J. :: !ri: ' .r^' r" ' "V1! :' : n.it:r - . 12 IQ 2 ft CL to 6 4 2 0 12 IQ * 8^ to- 6 t4 2 Q 10 8 At 6 4 to 2 0 ABERDEEN VCM TANK CONTINUOUS MONITORING UNIT -PERCENTAGE OF SAMPLES WITHIN CONCENTRATION RANGES lv .1'iKLH it.1' " :if' . ' \ T'-' ^I' _T l. ' 4 n b> 1 TjT W Hi 1 i . _. A . , ' HUl i 1 1 .............. 1 1" ..I-^1. , i ( . l. i . sjfj-i. `8LlEw i l ..- i : 1 -W .! | A :I^ **'l'RV?F4: ' vV <1^ A*4dt : .. .. ,i . &r- ' L. s-..r< ' :$ .r * F i. i/i t',' ; n 4. *: v.v Jh- K- *<. -4lt*l tT 1% ' :. %. i*' S' t^i -. r. ,. *.- +1" M p. Jj" It *a *il. M v r< 11 i w. .i 4? wit '*i- .hAI- fift" *r if * .; i--. -jUL s,t PV * Monitored only 14 days in August, 1976 Unit down all of May and June. -*L\ vr; VAB.0001050085 & 4 4 ABERDEEN OLD LARGE REACTOR VCM CONTINUOUS MONITORING UNIT TRENDS -PERCENTAGE OF SAMPLES 12 b- r, - i1' 8 o o 6 4 2 4 4 s 4 <, t. [ , ' I? A / r- . ,T. * r*" , \. - ^ rt *t l'* i F . . 'If t k ! ' "J i- ft r i-J*. 4, y. > . p 11 . A 4 * 4 2 4 V7 10 S CU *4* 6 m4 2 *0 Unit down all of May and June. Placed back into service 7/12/78 .. .. j- v l * 4 -F+ kKf H . VI 'v/ffr,- v 'i. . . 'lii***- &4%4*- 'V^ -f . * riZ-l.nr. J Cj .1 . . H.