1 IN TH E SUPREME COURT O F THE ST ATE OF NEW MEXICO

2 Opinion N um ber: 3 F ili ng D at e: M ar ch 3, 201 6

4 N O. S -1 -S C -3 3884 5 CONCEPTI ON AND ROSARIO ACOSTA et a l., 6 Pl ai nti ff

s/I nte rv en or s- Pe tit ion er s, 7 v

. 8 SHE LL W ESTE RN EXPLORATI ON AND 9 PRODUCTIO N, INC., and SHEL L OI L COMPANY, 10 D ef

en dants -R es pond en ts.

11 ORI GI NAL PROCEEDI NG ON CERTI ORARI 12 F re dd ie Jos ep h R om er o, D ist ri ctJu dg e

13 Tucker

Law F irm , P .C. 14 Steven L . T ucker 15 San ta Fe, NM 16 Law O ffice s of Martin N . B uchanan 17 Martin N . B uchanan 18 San D iego, CA 19 for Pe tition ers1 Ro de y , Dick as on , Slo an , Aki n & Ro bb , P.A.

2 Edw ard R. Ricco 3 Jocelyn C. D rennan 4 Alb uq ue rq ue , NM 5 fo r Re spon de nts1 OPIN ION

2 DA NIEL S, Justice. 3 I. INTR ODU CTION 4 { 1} Fr om

the 192 0s thr ough199 3, D ef en dants S he ll W es te rnE xpl or at iona nd 5 Production, Inc. and Shell Oil Com pany (collectively , Shell) engaged in oil andgas 6 ope ratio ns i n H obbs , N ewMe xic o. E nvi ro nm en ta l c ont am inatio n f ro m the se 7 ope ratio ns w as dis co ve re d y ears la ter, an d ov er tw o hundr ed

r es ide nts of

the 8 contam inated area brough t this to xic tort action against Shell for pers o n al injury 9 da m ag es that i nc lud ed

sy ste m ic lup us e ry

the m at osi s (lu

pus) an d othe r au toi m

m une 10 dis or de rs . P la int if

fs a lle ge that t oxi c ch em ic als fro m c ru de oil c au se d th ei r 11 au toi m

m une dis or de rs . T he y

c ha lle nge the dis tr ic t c ourt’ s e xc lus ionof the sc ie nti fi c 12 ev idence and expert testim ony they offer ed in supp ort of this theory , and they 13 ch al le nge the r es ult ing part ia l sum m ar y j udgm en t i n f

av or of S he ll. 14 { 2} W e hol d that the dis tr ic t co urt ap pli ed an inc or re ct standard of

a dm iss ibi lity

in 15 its evidenti ary

rulings andthat Plaintiffs’ causation evidence shou l d have been 16 adm itt ed

. Because sum m ar y j udgm en t a s to S he ll’ s c ulp ab ili ty f or the auto im

m une 17 di so rd ers was g ran te d t o S he ll as a res ul t of thi s im pr op er excl us io n of evi de nc e, we 18 reverse the summ ary j udgm ent an d rem and to the dis trict court for f urther 19 pr oc ee din gs.2

1 II . BACKGRO UND 2 { 3} Plaintiffs ar e re sidents of the W estgate subdi visio n i n Ho b b s. W estgate wa s 3 bui lt in the la te 197 0s o n and n ear anunl ine d sto ra ge pit w he re , dur ing it s oi l dr ill ing 4 ope ratio ns, S he ll ha d pl ac ed tox ic hy dr oc ar

bons in dir ec t co nta ct w ith the earth f ro m 5 the 194 0s unti l S he ll co ve re d th e pit w ith“ fi ll dirt” dur ing th e 1960s. S he ll did not 6 conduct anyenvironm ental risk assessm ent of the pit while it wa s in operation or after 7 it was c overed. S hell never reported r eleases or leaks of toxic c hem icals to the N ew 8 Me xic o O il Co nse rv at ionD ivi sio n and d id n ot n oti fy the W es tgate sub div isi on 9 build er that the hy dro carbon storage pit existed beneath Tasker D rive in the new 10 subd ivi sio n. 11 {4} Sh el l ha d c ondu ct ed oil an d gas o pe ratio ns o n th e G ri m es le as e. T he ope ratio ns 12 included st oring crude oil in th e Gr im es tank batter y , located j ust w est of the T asker 13 pit. Shell decom

m issio ned the Grim es tank battery in 199 3 an d t u rned the Gr im es 14 le as e ove r to Al tur a E ne rg y , L td. by 1997

. Ma ssi ve hy dr oc ar bon co ntam inatio n of the 15 soil, extending sixty -five f eet below gr ound level and into the aquifer, wa s discov ered 16 w hil e dis m an tli ng the G ri m es tank ba tte ry in 1997

. L at er that y ear, hom e bui lde rs in 17 W es tgate dis co ve re d ahard lay er of hy dr oc ar bon co ntam inants one to tw o f ee t be low 18 the gr ound

sur fa ce that vari ed

in thi ckne ss f

ro m se ve ra l i nc he s to se ve ra l f ee t. Be low3

1 that l ay er

w as oil y

soi l satur at ed

w ithtox ic hy dr oc ar

bons

. T he c ont am inatio n 2 extended across properties on bo th sides o f T asker D rive. Parts of the area rem ained 3 co ntam inate d at the tim e of tr ia l, de spi te y ears of atte m pte d re m edia ti on in vol vin g 4 rem oval of h undreds of t ruckloads of contam inated earth, m assive tents, the closure 5 of part of T asker D rive, noise, foul sm ells, and dusty air. 6 { 5} Plaintiffs asserted claim s against Shell for negl igence, strict liability , nuisance, 7 an d tr es pa ss and a lle ge d th at the y ha d su ff er ed inj ur ie s f

ro m the ir e xp osur e to 8 co ntam inatio n f

ro m S he ll’ s oi l op er at ion s. T he a lle ge d in j ur ie s inclu de d lu

pus an d 9 oth er auto im m une dis or de rs , ne ur olo gic al dis ea se s, an d r e s p i r at o r y dis ea se s. O nly

the 10 cl ai m s in vol vin g auto im m une dis or de rs a re a t i ssu e in this appe al

. 11 { 6} Plaintiffs sough t to off er the e xpert testim ony

of D r. Jam es Dahlgren that 12 Pl ai nti ff

s’ lup us and o the r au toi m m une dis or de rs w er e cau se d or a ggr av at ed

by 13 lon g- te rm

e xpos ur e to a m ixt

ur e of be nz en e and

oth er or ganic sol ve nts , hy dr oc ar bons 1 4 s u c h a s p r i s t a n e a n dp h yt a n e , a n dm e r c u ry ( t h e a g e n t s ) , a l l o f

w h i c h a r e t o xic 15 chem icals found in crude oil

. As support for this causation opini on, D ahlgren 16 pr ovi de d nu m er ous an im al a nd hum anstu die s th at li nke d th e ag en ts t o im m une 17 sy ste m

dis ru pti on, auto im

m une dis ea se s, a nd l upus . 18 { 7} Lupus is a com

plex and po tentially

fatal inflam

m atory disorder that can aff

ect4

1 vari ous part s of th e bo dy , inc lud ing the j oin ts, ski n, kidne y s, he ar t, lun gs, blo od 2 ve sse ls, a nd b ra in. P hy sic ians d ia gnos e lup us whe n apa tie nt p re se nts w itha t l ea st 3 fo ur of the A m er ic anCo lle ge of Rh eu m at olo gy ’ s “ E le ve n C ri te ri a of L upus . ” T he se 4 cr ite ri a inc lud e ra she s, ulc er s, a rthr iti s, a nd i m m unol ogi ca l di sor de rs . 5 { 8} H um an s and m ic e w ith lup us al so de m onstrate a de fi ci t of na tur al kil le r ce lls 6 ( N K C ) t h a tp l a y ac r i t i c a l r o l e i n t h e n o rma l f u n c t i o n i n g o f ah e a l t h y i mmu n e s ys t e m. 7 Dahlgren proffere d his own pub lished and p eer- review ed epidem iolog ical study that 8 qu a n t i f i e dP l a i n t i f

f s ’ e x p o s u r e t o t h e a g e n t s , g a t h e r e dP l a i n t i f f s ’ m e d i c a l h ist or ie s, 9 stu die d th ei r m ed ic al c ondi tio ns, c om pare d th es e re sul ts w ith tho se of a co ntr ol g ro up 10 in a nonexp osed comm unity , and discuss ed a num ber of toxicologi cal studies on m ice 11 that associated autoimm une disorders with exp osure to pristane (the anim al studies). 12 { 9} D ah lgr en ’ s st

udy obt ai ne d m ed ic al r ec or ds and que sti onna ir e re spon se s f ro m 13 al l P la int iffs, sa m

ples o f blo od f

ro m avol unt ee r subg ro up o f Pl ai nti ff s, sam ple s of 14 hous e dust

f ro m som e of the ir W es tgate hom es , a nd ana ly sis r es ult s of the a ir 15 m oni tor ed

by S he ll at m

ult ipl e loc at ion s inthe e xpos ed W es tgate ne ighbor

hood

. T he 16 sa m ple a na ly sis r es ult s w er e use d to m ea sur e the pr es en ce of the a ge nts in the 17 subj ec ts’ e nvi ro nm en t and i n the vol unt ee r subj ec ts the m se lve s. A s c om pare d to the 18 anal y sis r es ult s of

e qui va le nt s am

ple s ob ta ine d f

ro m vol unt ee rs in the c ontro l5

1 co mm un ity a nd f ro m the ir sur ro undi ngs, D ah lgr enm ea sur ed e le va te d le ve ls o f 2 p r i s t a n e a n dp h yt a n e i n P l a i n t i f f s ’ b l o o ds a mp l e s a n de l e v a t e dl e v e l s o f mer c u ry, 3 p r i s t a n e a n dp h yt a n e , b e n z e n e , a n do t h e r h yd r o c a r

b o n s i n P l a i n t i f

f s ’ h o me 4 en vir onm en ts. 5 { 10} D ah lgr en al so com pil ed the m ed ic al his tor ie s and p hy sic al e xa m inatio n r es ult s 6 fr om a“ vol unt ee r sa m

ple of 90 a dul t[ ] ” Pl ai nti ff s of the W es tgate sub gr oup an d f ro m 7 m em be rs of the none xpos ed co ntr ol co m m uni ty to co m

pare the oc curr en ce of

dis ea se 8 an d sy m pto m s in the tw o co m

m uni tie s. H e obse rv ed

a n “ [i ] nc re as ed

pr ev al en ce [] of 9 s ym p t o ms t h o u g h tt o b e p r e d i c t i v e o f au t o i mm u n e d i so rd er” i n P la in ti ffs ’ co m m u n i t y. 10 T he N K C w er e sign if ic an tly fe w er in the W es tgate r es ide nts than inr es ide nts of the 11 co ntr ol c om

m uni ty w hil e the pr es en ce of

B- ly m phoc yte s wa s si gni fi cantl y gr eate r in 12 the W estgate popu lation. The deficit of N KC in com b i n at i o n with elevated 13 B- ly m phoc yte s in dic at ed

abnor m al iti es in Pl ai nti ff

s’ im m une sy ste m s. 14 { 11} Dah lg ren ’s stud y of P la in ti ffs “ by qu es t i o n na ire an d m ed ic al reco rdrev ie w” 15 ide nti fi ed

thi rt ee n di ag nose d c as es of lup us o n tw o bl oc ks i n th e ar ea of the W es tgate 16 ne ighborhood onor

ne ar the T as ke r pit

. I n th e W es tgate c om m uni ty , dia gnos es of 17 lup us and r

he um at ic dis ea se , an oth er auto im m une dis or de r, w er e te n ti m es tho se in 18 the co nt ro l co m

m uni ty

. P la int if

fs “ got the dis ea se s . . . a ft er

m ovi ng i nto the6

1 ne ighbor

hood , ” an d m an y

of the m r ep orte d ale sse nin g or ev en a tot al r em iss ionof 2 the sy m pto m s a ft er

le av ing the W es tgate ne ighbor hood

. T o e xpl ai n th e pr ev al en ce of 3 these diseases in W estgate com pared to the unexpo sed control comm unity , D ahlgren 4 concluded th at the agents caused the statistically significant elevation in occurrences 5 of auto im m une dis or de rs . 6 { 12} D ah lgr en ’ s st

udy a cknow le dg ed that i t c oul d no t po int de fi nit ive ly

to an y 7 h u m an cases of pristane-induced lupus , but it ref erre d to a num

ber of other studies 8 dem onstrating that m ercury is “ conclusiv ely known” to c ause i mm u n e s y stem 9 dis ru pti on i n anim al s and hum an s an d th at be nz en e adve rs el y im pa ct s th e im

m une 10 sy stem

in hum ans. D ahlgren also refe rred to at lea st thirteen anim al studies 11 es ta bli shi ng tha t pr ist an e ex posure in m ic e ind uc es auto im

m un ity a nd l upus , one 12 stu dy statin g th at

pr ist an e co uld be inv olv ed in som e ca se s of hum an lup us, an d on e 13 stu dy ind ic at ing that ph ytane w oul d have asim ilar ef fect du e to i ts c om

para ble 1 4 mo l e c u l a r

s t r u c tu r e a n dt o x i c i t y. 15 { 13} Inhis a ff

idavit , D ah lgr ena sse rt ed that his study w as c ondu ct ed

pur suant t o th e 16 m ethodo log ic al standard s se t by the F ed er al Jud ic ia l C en te r’ s R ef er en ce M anua l on 17 Scientific Evidence ( 2d e d. 200 0)

. D ah lgr en ’ s st ud y inc lud ed ( 1) a n ana ly sis of 18 Plaintiffs’ med ical condition s throug h patient his tory , m edical re cords, phy sical7

1 ex am inatio n, a nd d ia gnos tic te sti ng, ( 2) a n ana ly sis of e xpos ur e inf

orm at iona nd the 2 te m por al r el at ion shi p betw ee n expo sur e and ill ne ss, (3 ) a re vie w of the m ed ic al a nd 3 scientific evidence to determ ine whether the exposu re can cause the illness (“ general 4 ca usa tio n” ), a nd ( 4) a n a ppl ic at ionof

the ge ne ral kno w le dge to the spe ci fi c 5 ci rc um stanc es of

the c as e to d et er

m ine w he the r the e xpos ur e did caus e the il lne ss, 6 includi ng consi deration of other possi ble causes (“ specific ca usation ”). 7 { 14} Da hl gr e n pr e se nt e d e vi de nc e thate xtr apo l a t i ono f the r e su l t s of

the a nim al 8 stu die s r ef

er en ce d inhis stu dy

pr ovi de d th e sc ie nti fi ca lly va lid ba sis f or his c au sa tio n 9 opi nio n inthi s c as e. H e de te rm ine d that the dose of pr ist an e Pl ai nti ff s re ce ive d f

ro m 10 pr olo nge d ho use hol d e xpos ur e, a dj ust ed f or the w ei ght of a hum an , w as w ith in the 11 ran ge of t he po te nt ia ll y “ ha rm fu l d os e” d et erm in edin th e an im al s t u di es . He 12 dis cu sse d se ve ra l othe r stu die s of oil fi el d ou tbr eaks o f au toi m m une dis ea se , one of 13 w hic h c ite d ar at e of

lup us tha t w as w el l abov e the na tio na l r at e but onl y one e igh th 14 the rate of lupu s found in W estgate. 15 { 15} D ah lgr ena lso r ule d ou t se ve ra l po ssi ble a lte rn at ive e xpl an at ion s f or the 16 el ev at ed

oc curr en ce of

auto im m une dis or de rs in W es tgate , suc h a s geneti c 17 sus ce pti bil ity

or dr ug- ind uc ed auto im m uni ty

. H e the n hy

pothe si ze d th at

the a ge nts 1 8 f o u n di n th e We s t g a t e c o mm un ity , in cl ud in g p ris tane , p h yt a n e , b e n z e n e , a n dmer c u ry,8

1 have a sy

nergistic effe ct and are m ore toxic in com binatio n than the i r add itive, 2 co m p ar ab le, indiv idual tox icities. H e cited the R ef er en ce G uid

e on T ox ic olo gya nd 3 the E nvi ro nm en ta l P ro te ct ionA ge nc y gui de lin es r eg ar din g th e co nc er te d e ff ec t of 4 m ix tu res of t ox ic ag en ts on th e b od y . See Be rn ar d D. G old ste in & Mary S ue H en if

in, 5 R ef er en ce G uid

e on T ox ic olo gy , in Fe d. Jud. Ctr ., Refere nc e M anua l on Sc ie nti

fic 6 Ev idence 401 , 429 , 436 (2 d ed

. 2000 ); G uid el ine s fo r the H ea lthRi sk A sse ssm en t of 7 Ch emic al Mi x tu re s , 5 1 Fe d . R eg . 3 4 0 1 4 , 3 4 0 1 4 -3 4 0 2 2 (S ep t . 2 4 , 1 9 8 6 ). Ev en Sh el l ’s 8 ex pe rt a gr ee d th at

it is impo rtant f

or a n e xpe rt

to co nsi de r howm

ult ipl e ch em ic al s 9 int er ac t and t o us e sc ie nti fi c j udgm en t t o de te rm ine w he the r the y int er ac t. 10 { 16} Dahlgr en co n s idered all of this evidence and m ore before concludin g that 11 Pl ai nti ff

s’ inh al at ion , ing es tio n, an d abso rp tio n of the co m bin at ionof

vari ous tox ins 12 from She l l ’ s oi l a nd

g a s op e r a t i on s c aus e d or a gg r a vat e d t he i r

l up us a nd

other 13 au toi m

m une dis or de rs . 14 { 17} T he dis tr ic t c ourt e xc lud ed D ah lgr en ’ s st ud y of

blo od p ri stane da taa nd h is 15 determ ination of Plaintiffs’ cum ulative dos e fr om

prolong ed exposu re a s unreliable, 16 an d P la int if

fs di d no t ch al le nge tho se r uli ngs on a

ppe al

. Bu t the dis tr ic t c ourt a lso 17 ex cl ude d the an im al stu die s an d D ah lgr en ’ s stu dy its el f as not re le vant, reason ing 18 the y f ai le d to show ge ne ra l c au sa tio n be tw ee n th e m ixt ur e of ide nti fi ed

c he m ic al s and9

1 lup us. Co ntr ar

y to D ah lgr en ’ s a ff

idavit , the dis tr ic t co ur t f ound that he ha d no t 2 co n s i d e r e d

th e d o s e - r e s p o n s e r e l at i o n s h i p ne ce ssary f or inf er ri ng c au sa tio n inhum an s 3 fr om tox ic olo gic al r es ult s ina ni m al s and st at ed that the a nim al stu die s w er e “ so 4 dissi m ilar to the facts presented [t] herein that the [district c] ourt d[ id] not find th em 5 relevant. ” It c onclud ed that Dahlgren’ s study had “ lim ited value as a basis f or a causal 6 co nne ct ionopi nio n” be ca use it w as a “ hy

pothe tic al ” stu dy “ adm itt ed ly don e onl y

f or 7 co m pari son pur

pose s” a nd the re fo re that i t ha d f ai le d to “ br idg e the ga

p f ro m 8 association to causation” and could no t stand alone to s uppo rt Plaintiffs’ claim s of a 9 causal re lationsh ip between the alleged m ixture and lup us. A s a result, the district 1 0 court excluded Dahl g re n ’s ca u s at i o n o p i n i o n du e t o “ i n s u ff i ci en t ” e v identiary

suppo rt 11 an d, ba se d onthe c onse que nti al la ck of ca usa tio n ev ide nc e, gr an te d S he ll’ s m oti on 12 for sum

m ary j udgmen t o n Plaintiffs’ claim s for dam ages from lupus and other 13 au toi m

m une dis or de rs . 14 { 18} Plaintiffs appealed the grant of sum m ary j udgm ent, c hallengin g the district 15 co urt’ s e xc lus ion s of

the a nim al stu die s and D ah lgr en ’ s stu dy ba se d on r el ev an ce a nd 16 it s ex cl us io n of Dah lg ren ’s c au sa ti on op in io n fo r “ in su ffi ci en t” ev id en ce. Ac osta v. 17 Shell W

. E xpl. &Prod., Inc. , 201 3- N MC A -0 09, ¶¶ 1, 12, 293 P. 3d 917. T he Co urt of 18 Appe al s a ffirm ed the dis tr ic t c ourt’ s gr an t of sum m ar y j udgm en t, hol din g th at

the10

1 dis tr ic t cour

t did not abus e its dis cr et ion w he n it conc lud ed that D ah lgr en ’ s st udy a nd 2 the a nim al stu die s w er e “ not suf fi ci en t” in ei th er bri dgi ng the a na lytic al ga p f ro m 3 as sociatio n to c au sa tio n or in es ta bli shi ng c au sa tio n be tw ee n th e ag en ts and 4 Pl ai nt iff

s’ lupu s an d a ut oi m

m un e d is or de rs . Id

. ¶ ¶ 27, 30, 33. 5 { 19} The C ourt of Appeals interpreted the district court’ s eviden t iary ruling that 6 Dah lg ren ’s stud y

di d n ot “ fit ” th e cas e as an is su e o f rel e va nc e. See id. ¶ ¶ 20, 28 7 (s t a t i ng t hat “ t he di str i c t c ourt sp e c i f i c a l l y c ho se no t t o a ddr e ss w hether D r. 8 Da h l g re n ’s m et h o d o l o g y wa s re l i ab l e” an di n s t ea d“ ex cl u d ed Dr

. Da h l g re n ’s 9 epidem iolog ic studyand his op inion testim ony on the basis o f re levance”). The Court 10 of Appe al s a gr ee d wi th the dis tr ic t c ourt, statin g th at “ Pl ai nti ff

s c oul d no t art ic ulate 11 any study , other than D r. Dahlgren’ s own studyof the W estga t e p o pulatio n, that 12 would supp ort the opin ion that the petrochem ical m ixture caused the lupu s and other 13 au toi m

m une dis or de rs ide nti fi ed

in thi s c as e” a nd tha t “ D r. D ah lgr en ’ s study is o nly 14 rel ev an t t o s ho w a ge ne ral ly hig he r in ci de nc e o f c e r t a i n m ed ic al di so rd ers in two 15 co m m uni ty gr oups but is insu ff

ic ie nt to est ab lis h a gene ra l causa tio n link to l upus a nd 16 other autoimm

une diso rders. ” Id

. ¶ ¶ 26, 32. W e gr an te d c er

tio rari a nd n owr ev er se the 17 Co ur t o f App eal s an d t he di st ric t co ur t. See Ac o s t a v . S h e l l W. , 201 2- N MC E RT -0 12. 18 III. STA ND AR

D O F REVIE W11

1 { 20} G ener al ly , the a dm iss ionor e xc lus ionof

e vid en ce is re vie w ed

on a ppe al f or 2 ab us e o f di sc ret io n. State v . D owney , 2008 -N MS C- 061, ¶ 24, 145 N

. M. 232, 195 P

. 3d 3 1244

. Bu t in thi s ca se , the thr es hol d que sti on is w he the r the dis tr ic t c ourt a ppl ie d th e 4 co rrec t ev id en ti ary st an da rd , a leg a l qu es ti on we rev ie w de n ov o. State v. T orres , 5 1999 -N MS C- 010, ¶

28, 127 N

. M. 20, 976 P

. 2d 20 . We al so r ev ie wde nov o th e 6 related inq uiry

of w hether the district court properly granted Shell’ s m otion for partial 7 su m m ary jud gm en t. See Smith v. Durden , 2 0 1 2 -N M SC -0 1 0 , ¶5 , 2 7 6 P. 3 d 9 4 3 (“W e 8 vie wthe f

ac ts i n th e lig ht m ost

f av or ab le to the party oppo sin g the sum m ar y j udgm en t 9 and indu lge all rea sonable inferences in favor of a t ri al o n the m erits.” ). Sum m ary 10 j udgm ent is a

ppropriate only wher e “ there is no genuin e issue a s to any m aterial f

act 11 and . .

. the m ovin g party is entitled to a j udgm ent as a m atter of law. ” Rule 1-056(C) 12 NMRA. 13 IV. DISC US SION 14 { 21} “ Adm issib ility

is a m i n i m al standard for individu al item s of evidence, 15 includi ng expert opin ions.” Sta te v . Co nsau l , 201 4- N MS C- 030, ¶ 67, 332 P

. 3d 8 50. 16 “ [T ] o be a dm iss ibl e anit em of ev idenc e ne ed

onl y a dd s om ethin g to the de ba te ; i t 17 ne ed onl y have a‘ te nde nc y

to m ak e a fa ct

m or e or le ss proba

ble than it

w oul d be 18 without the evidence.’ ” Id

. (quoting Rule 11-401 NMRA ).12

1 A . Th e A dm iss ib ili tyof Ex pe rtTe st im on y U nd er N ew M ex ic o L aw 2 { 22} T he a dm iss ibi lity of e xpe rt te sti m ony

in N ewMe xic o is gui de d by Ru le 11- 702 3 NMR A, which sets out three requirem ents: “ (1) that the expert be qualified; (2) that 4 the te sti m ony be of as sis tanc e to the tr ie r of fa ct ; an d (3 ) that the e xpe rt ’ s te sti m ony 5 be ab ou t sc ie nt ifi c, te ch ni cal , o r ot he r sp eci al iz edkn owl ed ge wit h a rel iabl e b as is .” 6 Downey , 200 8- N MS C- 061, ¶ 25. 7 { 23} T he dis tr ic t c ourt f ound that D ah lgr enw as qua lif ie d to pr ovi de opi nio ns 8 regarding specific and general c ausation in this case. Further, the district court 9 “ [d] isregard[ed] the questio ns of invalid data, unreliable m ethodo logyand the other 10 iss ue s r ai se d by Sh el l, ” fo cu sin g ins te ad on the se co nd adm iss ibi lity re qui re m en t of 11 whether Dahlgren’ s testim ony would assist the trier of fa ct. This requirem ent “ goes 12 pr im ar ily

to re le vanc e” a s “ [e ] xpe rt te sti m ony

w hic h do es not

r el at e to any

iss ue in 13 the case is not relevant and, ergo, non-helpful.” Daubert v. Merrell Dow Pharm., Inc. , 14 509 U.S . 579, 591 (1993) (internal quotatio n m arks and citation om itted). 15 { 24} S ho rt l y

a fter Dauber t , thi s C ourt st at ed that the “pe rt ine nt i nqui ry ” fo r 16 de te rm ini ng whe the r ex pe rt te sti m ony

w ill a ssi st the tr ie r of

f ac t un de r the se co nd 17 re qui re m en t of

Ru le 11 -7 02 “ m

ust f oc us o n th e pr oof

of r el ia bil ity of the sc ie nti fi c 18 technique or m ethod upon which the expert te stim ony is prem ised.” State v. A lberico ,13

1 1993 -N MSC- 047, ¶ 53, 116 N. M. 156, 861 P. 2d 192. A court m ust determ ine whether 2 the pr of

fe re d expe rt te sti m ony is “ suf fi ci en tly tie d to the f

ac ts o f the c as e that i t w ill 3 aid the j ury in r esolvin g a fa ctual dispu te.” Downey , 2008-NMS C-061, ¶ 30 (internal 4 quot at io n m ark s an d c it at io n o m it te d) . “ [T]he sc ie nt ifi c m et ho do lo gy [m us t] ‘ fi t[ ] ’ the 5 facts of the c ase and thereby prove[] what it purports to prove.” Id

. T h e i n qu i ry i s “a 6 fl ex ibl e one , ” an d it s f

oc us “ m ust be sol el y on pri nc ipl es an d m ethodo log y , not on the 7 c on c l us i on s t hatthe y

g e ne r a t e . ” D aube rt , 509 U

. S. a t 59 4- 95; se e als o Alberico , 8 199 3- NMSC -0 47, ¶

72 ( “ T he re is no r equir em en t tha t a sc ie nti fi c te ch nique or 9 me t h o dp ro v e c o n c l u s i v e l y w h a ti tp u r p o rt s t o p r o v e . ” )

. A s t h e U n i t e dS t a t e s S up r e me 10 Co urt e m

pha siz ed , “ it w oul d be unre as ona ble to co nc lud e that the sub j ec t of sc ie nti fi c 11 te sti m ony

m ust be ‘ known’ to a ce rt ai nty ; arg uably , the re a re no certa int ie s in 12 science. ” D aube rt , 509 U

. S. a t 59 0. Rathe r, “ the sc ie nti fi c pr oc ed ur e w hic h su

ppor ts 13 the te sti m ony

[ m ust be ] c ap ab le of

supportin g op ini ons ba se d up on a r ea sona ble 14 probabilit y

rather than conjecture .” Alberico , 199 3 -N MSC- 047, ¶ 98 (internal 15 quot ation m arks and citation om itted). 16 { 25} Since D aube rt , the f ed er al c ourts h av e co nti nue d to r ef ine the stand ard s for 17 adm issib ility

of expert testim ony , but N ewMexico ha s n o t followed these changes 18 in l ocks te p wit h th e fe de ra l c ourts. I n Kumho Tire Co. v. Carmichael , the United14

1 States Suprem e Court extended a trial court’ s gate-keeping function under D aube rt 2 to in cl ud e ex pe rt t es ti m on y ba se d o n n on sc i e n ti fic ex pe rie nc e an d t rai ni ng . See 3 Ku mho T

ire Co

. , 526 U

. S. 137 , 151 ( 1999 ). Y et , in Torres , this Court lim ited 4 application o f the D aube rt / Alberico requirem ents to expert testim ony that requires 5 sc ie nt ifi c kno wled ge . See Torres , 1999-NMS C-010, ¶ 43. A ccord i ngly , c omm ittee 6 com m entary on Rule 11-702 warns of the differ ences betw een fe d er al an d New 7 Mexico law in apply ing th e D aube rt req ui rem en ts

. See Ru le 11- 702 co m m . cmt. 8 (“New Mex ico ha s no t a dopt ed the c hange s m ad e to the f ed er al r ule in 2000 to 9 incorporate the requirem ents of Daubert v. Merrell D ow Pharmace uticals, Inc. , 509 10 U. S. 579 (1993), in light of the differe nces betwee n federa l law and Ne w Mexico law 11 regarding whether D aube rt appl ie s to non sc ie nti fi c te sti m ony . ”) ; s e e als o Banks v. 12 IM C Ka li um Carl

sbad P ota sh C

o. , 200 3- N MS C- 026, ¶

19, 134 N

. M. 421 , 77 P

. 3d 13 1014 (observing th at “ after Ku m ho T ire Co

. , we ap p l y D aube rt som ewha t di ff

er en tly 14 than do th e fe deral courts”). 15 { 26} In Ge neral Elec t r i c Co . v . J oiner , the United States Suprem e Court af firm ed 16 a distri ct co urt’ s dete rm inatio n to e xc lud e ane xpe rt ’ s c au sa tio n te sti m ony on g ro unds 17 of re l evance, notin g that “ [a] court m ay conclude that there is sim ply too great an 18 analytical gap betwee n the data and the opin ion proff ered. ” 522 U. S. 136, 146 (199 7).15

1 Inthe c as e at

bar, both th e dis tr ic t c ourt and the Co ur t of Appe al s c ite d th is Joiner 2 pr opos iti on a s ake y

reaso n f or e xc lud ing D ah lgr en ’ s ge ne ra l c au sa tio n te sti m ony 3 pe rt ai nin g to P la int if

fs ’ de ve lop m en t of lupus a nd o the r au toi m m une c ondi tio ns and 4 determ ined that the analytical gap betwee n the evidence presented and the inference 5 dr awn on th e ul ti m at e is su e o f cau sa ti on was t oo wid e. See A co sta , 201 3- N MC A -0 09, 6 ¶¶ 23- 24, 27. 7 { 27} But NewMexico has never adopted the Joiner rule t hat a j udge m ay

rej ect 8 ex pe rt te sti m ony w he re the “ an al ytic al ga p” be tw ee n the unde rl y ing ev ide nc e an d th e 9 expert’ s conclusio ns is “ too great,” see 522 U

. S. 146, an d w e re fu se to do s o inthi s 10 case. Historically , this Court has placed great value o n al lowing a j ury to hear 11 ev ide nc e an d de ci de ac as e on the m erits

. See, e . g. , Za m ora v. St. V inc en t H osp. , 12 2014 -N MSC- 035, ¶¶ 10-11, 335 P. 3d 12 43 (stating that this Court has m ainta i n ed 13 N ewMe xic o’ s no tic e ple ad ing r equir em en ts b as ed on o ur “ polic y

of a voi din g 1 4 ins ist en c e o n h y

p e rt e c h n i c a l f

o rm a n d e x a c t i n g l a n g u a g e ” a n d o n a r a t i o n a l e of 15 re sol vin g di sput es on the ir m er its ); Rom ero v. Philip Morris Inc. , 201 0- N MS C- 035, 16 ¶ 8, 148 N .M. 713, 242 P. 3d 280 (“ Ne w Me xico courts, unlike federal c ourts, view 17 summ ary

j udgm ent with disfavor, pre ferr ing a trial on the m erits.” ). 18 { 28} Joiner is inconsistent w ith longstandi ng N ew Mexico law t h at leaves16

1 cred ib il it y

de te rm in at io ns an d wei gh in g o f th e ev id en ce t o t he tri er of fact

. Se e, e . g. , 2 State v. H

ughey , 200 7- N MS C- 036, ¶ ¶ 15, 17, 142 N

. M. 83, 163 P. 3d 4 70 ( co nc lud ing 3 that evidentiary

rulings b ased on witness credibility usurp the role of the j ury

and that 4 doub t as to sc ie nti fi c co nc lus ion s sh oul d be r es olv ed not by e xc lus ionbut

by c ro ss5 exam ination , r ebuttal evidence, and argum entation). “ Given the capabilities of j urors 6 an d th e lib er al thr

ust of the r ule s of e vid en ce , w e be lie ve an y doubt r eg ar din g th e 7 adm issib ility

of scientific evidence shou ld be resolved in favor of adm issio n, rather 8 than exclusio n.” Lee v. Martinez , 2004 -N MS C- 027, ¶ 16, 136 N

. M. 166 , 96 P

. 3d 2 91. 9 “ ‘ V igo ro us c ro ss- ex am inatio n, pr es en ta tio n of c ontrary e vid en ce , a nd c ar ef

ul 10 ins tr uc tio n onthe bur de n of pr oof a re the tr ad iti ona l and a ppr opr ia te m eans o f 11 a t t a c ki ng s haky

b ut a dm i ss i bl e e vi de nce.’ ” Id

. ¶ 48 ( quot ing D aube rt , 509 U. S. at 12 596). 13 B. P ro of

of C au sat ion in To xic To rtLi ti gat ion 14 { 29} A lth oughli tig at ionof tox ic tor ts i s of te n c om ple x, thi s do es not

a lte r the 15 di st ric t co ur t’s g at e k e e p i n g fun ct io n. Th e cru ci al is su e in th is cas e is cau sa ti on . To 16 pr ove c au sa tio n inatox ic tort ca se , a pla int if f m ust fi rs t show that a

sus pe ct ed

c au se 17 actually

“ is capable of ca

using a particular

in ju ry or condition in the general 18 popu lation.” No rri

s v. B ax te r H

ea lth ca re Co rp. , 397 F. 3d 87 8, 881 (10th Cir. 2005).17

1 A ft er e sta bli shi ng s uc h ge ne ra l c au s at i o n , th e pla int if f m ust the n de m onstrate spe ci fi c 2 cau sa ti on : t ha t t he su sp ect edcau se di d a ctua ll y cau se th e p la i n t i f

f’s in jury. Id

. 3 Beca use the district court determ ined that Dahlgren ’s s tudyand the proffer ed 4 testim ony wo u l d not assi st the trier of f act in determ ining whether the chem ical 5 m ixt ur e at iss ue in thi s ca se is ca pable of ca

usi ng lup us or ot he r au toim m une 6 dis or de rs , it

ne ve r re ac he d th e que sti on o f spe ci fi c ca usa tio n. 7 { 30} “ Whe n th e conn ec tio n be tw ee n an a ge nt and d ise as e is s tr ong an d w el l 8 doc um en te d, ge ne ra l- ca usa t i o ni s s u e s f

a d e i n t o th e b a c k g r o un d

. ” R e state m en t ( T hir d) 9 of T orts: P hy sic al a nd E m oti ona l Harm § 28 c m t. c (3 ) (A m . L awI nst

. 201 0)

. Bu t 10 dem onstrating that a chem ical is capable of causing a particular injury in the general 11 popu lation is o ften difficult in first-exposure cases wher e it has not been the sub j ect 12 of e xte nsi ve sc ie nti fi c an al y sis

. 13 { 31} W e ag re e w ith oth er j ur isd ic tio ns tha t “ [t ] he fi rs t seve ra l vic tim s of ane wtox ic 14 tort sh ould no t be barr ed f ro m havin g th ei r day

in co urt” sim

ply be ca use sc ie nti fi c 15 an al y si s o n a pa rti cu la r ch em ic al c au se ha s n ot y etbe en ful ly dev el op ed

. Turner v. 16 Io wa F

ire E qui p. Co

. , 229 F

. 3d 1 202, 120 9 ( 8thCi r. 200 0) ; se e als o Best v. L owe’s 17 Hom e Ctrs., Inc. , 563 F

. 3d 1 71, 180 -8 1 ( 6thCi r. 200 9) ( “ [T ] he re is no r equir em en t 18 that a m edical expert m ust alw ay s cite publ ished studies on general causation in o rder18

1 to reliably

conclude that a particular obj ect ca used a particular ill ness.” ( internal 2 quot at ionm ar

ks and c itatio n om itt ed )) ; No rri s , 397 F. 3d at 8 82 (“ In cases where there 3 is n o e pid em iol ogy ch al le ngi ng causa tio n ava ila ble , ep ide m iol ogi ca l evi de nc e w oul d 4 not necessarily

be required. ”). 5 { 32} Insom e ca se s w he re e pid em iol ogy is ab se nt , juri sts a nd s ci en tis ts h av e 6 em ploy ed the nonform

ulaic guid elines of Sir Austin Bra dford Hill to assess whether 7 a n e pi de m i ol og i c a l st

udy ’ s f i nd i ng of a n a ss oc i a t i on be t w e e n a su bs t a nce and an 8 inj ur y sup porte d an inf

er en ce of ca

usa tio n. Mi ch ae l D

. G re en , D

. Mi ch al F re edm an , 9 & Leo n Go rd is , R ef

er en ce G uid

e on E pid em iol ogy , i n F ed . Ju d. Ct r., Re ference 10 Manual on Scientific Evidence 599 -6 00 & 599 n. 141 (3 d ed

. 201 1)

. T he Br ad fo rd H ill 11 factors that guide experts in m aking judgm ents about causatio n includ e: (1) tem poral 12 re la tio nshi p, (2 ) st re ngth of the a sso ci at ion , ( 3) dos e- re spon se r el at ion shi p, ( 4) 13 re pli catio n of

the fi nd ing s, ( 5) bio log ic al pla usi bil ity ( co he re nc e w ithe xis tin g 14 knowledge), ( 6) consideration of a lternative explanation s, (7) cessation of exposu re, 15 (8 ) sp eci fic it y

of t he ass oc ia ti on , and (9) co ns is te nc y w i t h o t he r kn owl ed ge . Id

. at 16 600. These c riteria are nonexclusive, and no one factor is dispositiv e in the gener al 17 cau sa ti on in qu iry. See id. 18 { 33} In ess ence, the Bradford H ill factors m easure the a bilityof an epidem iolog ical19

1 studyto determ ine whether an association foun d by the studyis sufficient to satisfy 2 anult im at e que sti on o f fa ct r eg ar din g c au sa tio n or w he the r the a sso ci at ionis m er el y 3 sp ur io us . See Milward v. Ac uity Specialit y Prods . G rp., Inc. , 639 F. 3d 11, 17 ( 1st Cir. 4 2011 ) (d es cr ibi ng the Br ad fo rd H ill facto rs a s asc ie nti fi c m ethod of w ei ghi ng the 5 evide nc e to m ake causal deter m ination s, involvin g “ a m ode of logical reasoning o ften 6 de sc ri be d as ‘ inf

er en ce to the be st ex plana tio n. ’ ” (c itatio n om itt ed )) ; G re enet a l., 7 supra a t 59 8 ( “ [E ] pid em iol ogy c annotpr ove c au sa tio n; r athe r, c au sa tio n is a 8 jud gm en t fo r ep id em io lo gi st s an d o th ers in te rp ret in g t he ep id em io l o g i c d at a.”). As 9 the F ir st C ir cu it not ed , “ [i ] n th is m ode of re as oni ng, the use of sc ie nti fi c j udgm en t i s 10 ne ce ssary , ” an d “ [t ] he fa ct that the ro le of j udgm en t i n [ thi s] appr oa chis m or e re ad ily 11 ap pare nt than it

is in o the r m ethodo lo gi es do es not m ean th e ap pr oa chis an y le ss 12 scientific.” M

ilw ard , 639 F

. 3d at 18

. 13 { 34} Whil e the re le vanc e of a part ic ular m ethodo log y de pe nds on the r el at ion shi p 14 of th e m et ho do lo gy to th e fact s and ci rcu m st an ces of each cas e, see Downey , 200 8- 15 NMS C-061, ¶ 30, application o f the Bradford H ill factors in assessing g eneral 16 cau sa ti on is wid el y

acce pt ed

. Se e, e . g. , Green et a l., supra at 598- 606 (d es cr ibi ng 17 application o f the Br adford Hill cr iteria in d eterm ining whether an established 18 association b et we en exposu re to an agent and developm ent of a disease is ca usal);20

1 Restatem ent (T hird) of T orts: Phy sical an d Em otion al Harm § 28 cm t. c (3) (A m . L aw 2 In st. 2010 ) (d es cr ibi ng the Br ad fo rd H ill cr ite ri a fo r as se ssi ng whe the r ana sso ci at ion 3 is cau sa l i n a n a na lysis of g en eral cau sa ti on ); I an S. Spe ch le r, Physicians at the Gates 4 of D aube rt: A L ook

at the A dm iss ibi lit

y of D iff er en tia l D iag

nosi s Testi m ony to S

how 5 E xt ernal Ca usat ion in Tox ic T ort L iti gat ion , 26 Re v. Litig. 739, 742 (2007) (“ Ge neral 6 ca usa tio n te sti m ony

sho uld r el y on hard sc ie nc e, a nd c ourts s houl d e va luate the 7 reliability

of that science under the Br adford Hill cr iteria. ”). 8 C . D ah l g r e n ’ s T e s t i m o n y a n d t h e S t u d i e s H e R e l i e d o n W e r e P r o b a t i v e of 9 Causation and Should Have Been Ad m itted 10 { 35} Dahlgren’ s causation op inion , his study , and the anim al studi es it relied on are 11 re le vant and a dm iss ibl e if the y de m onstrate ava li d sc ie nti fi c re la tio nshi p th at is 12 probative of causation, regar dless of their sufficiency t o sustain Plaintiffs’ entire 13 bu rd en of p ro of

. See A m bros iniv . L abarraqu e , 101 F. 3d 1 29, 135 ( D

. C. Ci r. 199 6) 14 (“ T he dis posi tiv e que sti on [ co nc er nin g r e l e vanc e] is w he the r the te sti m ony w ill a ssi st 15 the trier of fact to understand the evidence o r to determ ine a fa ct in issue, not whether 16 the testim ony

satisfies the plaintiff’ s burden on the ultim ate issue at trial. ” (internal 17 quot ation m arks and citation om itted)). 18 { 36} Re ly ing on Joiner , the di st rict c ourt e xc lud ed the a nim al stu die s be ca

use it 19 found th em

“ not . .

. relevant” as “ studi es . . . so diss im ilar to t he fac ts” associated21

1 w ithP la int if

fs ’ e xpos ur es , a nd it em

pha siz ed the ne ed to c onsi de r the “ dose -r es pons e 2 relationship ” w hen “ in fe rr i n g hum an causation from anim al studies.” T he district 3 co ur t c o n c l u d e d t h a t i n t h e ab s e n c e o f s u c h “ s c i e n t i f i c a l l y r e l i ab l e e v i d e n c e . . . to 4 supp ort ge ne ra l c au sa tio n be tw ee n th e [a ge nts ] a nd l upus . . . , the stu dy doe s no t ‘ fi t’ 5 an y is su e to be pre se nt edto th e jury, andis in ad m is si bl e.” 6 { 37} The scie nce of toxicol ogy provides evidence that a certa in dos e of a particular 7 ch em ic al cau se s p art ic ul ar ef fec ts in th e b od ie s o f hu m an s o r ot he r an im al s. See 8 Bern ardD. Gold st ei n & Mary Sue Hen ifi n, R ef er en ce G uid

e on T ox ic olo gy , in Fe d. 9 Ju d. Ct r., Re

ference M

anua l on Scientif

ic E vidence 633, 635 -3 7, 641 ( 3d e d. 201 1) 10 (d es cr ibi ng d ose -r es pons e as howthe r es pons e to the ch em ic al vari es w ithc hangi ng 11 dose of

the c he m ic al ). A dose -r es pons e re la tio nshi p, w hil e not es se nti al e vid en ce of 12 a causa l r el at ion shi p be tw ee n an a ge nt and d ise as e, is co nsi de re d stro ng e vid en ce of 13 a cau sa l re la ti on sh ip

. See Green et a l., supra at 6 03. In particular, consideration of a 14 dose-response relationsh ip is im portant when inferring hum an causation from anim al 15 st ud ie s. See id. a t 56 3. 16 { 38} To support Dahlgren’ s inference from the anim al studies th at the agents caused 17 Plaintiffs’ illnesses in this ca se, the results of the anim al studi es needed to be adj usted 18 by ext rap ol at io n t o h um an s. See G old ste in & H en if in, R ef er en ce G uid

e on22

1 Toxi co log

y , in Fed . Ju d. Ct r., Re

ference M

anua l on Scientif

ic E viden ce a t 64 6, 661 -6 3 2 (3 d e d. 201 1) ( de sc ri bin g scie nti fi c iss ue s invol ve d wi th e xtr ap olatin g th e re sul ts o f 3 an anim al studyto hum ans). Contrary to the assertions of the lower courts, Dahlgren 4 pr es en te d e vid en ce that the re sul ts of the a nim al stu die s a dj ust ed by e xtr ap olatio n to 5 the hum an s inthi s c as e co uld pr ovi de asc ie nti fi ca lly

va lid ba sis f or his inf er en ce of 6 ca usa tio n inP la int if

fs

. His m ethodo log y

r ef le ct ed that the harm fu l do se of

pr ist an e 7 the m ic e re ce ive d, a dj ust ed fo r the w ei ght of ahum an , w as c om

para ble to Pl ai nti ff

s’ 8 dose determ ined by

their daily

inhaled expos ure (dose per day or co n ce n t ra t ion), 9 ad jus te d fo r th e p ro lo ng eddu rat io n of tha t ex po su re t o c on ve rt t o d os e. See id. a t 63 8 10 & n

. 12 ( “ D ose is a func tio n of bo th c onc en tr at iona nd d ur at ion

. ”) , 681 ( de fi nin g do se 11 as “ [a] pro du ctof . . . th e co nc en tra ti on of a ch em ic al . . . agen t an d t he du rat io n . . . 12 of e xpos ur e” ). T his res ult of D ah lgr en ’ s e xtr ap olatio n f ro m the a nim al stu dy

is 13 ev ide nc e that su

ppor ts an in fe re nc e of ca

usa tio n. T he c re dib ili ty

of the e xtr ap olatio n 1 4 a n dth e we i g h t

i ts h o u l db e a c c o r d e da r e qu e s t i o n s f o r t h e ju ry. 15 { 39} Th e d i s t r i c t c o u rt ’s b as i s fo r e x cl u d i n g Da h l g re n ’s s tu d y wa s t h e s tu d y’ s 16 “ fail[ure ] to bridge the gap from association to causation.” In his stu dy , D ahlgren 17 co lle ct ed

m ed ic al a nd e nvi ro nm en ta l dataf ro m th e W es tgate P la int if fs a nd the ir 18 ne ighbor

hood a nd f ro m the une xpos ed

c on tro l c om

m uni ty sub j ec ts and the ir23

1 ne ighbo rh ood. H e co nc lud ed that P la int if

fs ’ c om m uni ty sho w ed both hi ghe r le ve ls 2 of the tox ic a ge nts a t i ssu e an d adr am at ic pr ev al en ce of lup us and s ym

pto m s of 3 au toi m m une dis ea se c om

pare d to the co ntr ol co m

m uni ty

. A n e pid em iol ogi ca l st udy 4 co m pil es inf orm at ion on the de te rm inants of adis ea se in a popu la tio n to e sta bli sh a 5 co rr el at ion( or

“ as soc ia tio n” ) be twee n atox ic a ge nt and the dis ea se a nd t o m ap the 6 “ incidence, distribution , and etiolo gy of [th e] disease in hum an popu lations.” Gr een 7 etal., supra a t 55 1, 623

. 8 { 40} H av i n g e s t ab l i s h e d a n a s s o c i a t i o n b e t w e e n t h e c h e m i c a l e x p o s u r e an d 9 Plaintiffs’ diseases, Dahlgren then dem onstrated, consistent with the widely acce pted 10 Br ad fo rd

H ill gui de lin es , that the a sso ci at ionr ev ea le d by his e pid em iol ogi ca l st

udy 11 wa s cau s al. Consist ent with expectations of the dose-respons e in a ca usal 12 re la tio nshi p, his stu dy f ound that the oc cu rren ces of

lup us and o the r au toi m

m une 1 3 d i s e a s e s i n t h e e x p o s e d P l a i n t i f f s s i g n i f i c a n t l y e x c e e d e d t h e o c c u rr e n c e s i n th e 14 unexpo sed control grou p and that th e s y m pt om s m ani f

e st e d a fter P laintiffs’ exposures 15 and lessened or disa ppeared if P laintiffs m oved away from the are a. Dahlgren 16 extrapolated the harm ful dose of pristane foundto indu ce lupu s in m ice to a hum an 17 eq u i v al ent and determ ined that Plaintiffs had received a dose within that range. In 18 additi o n t o the anim al studies in volv ing prist ane, Dahlgren cited num erous other24

1 stu die s w he re e nvi ro nm en ta l c ont am in an ts consi sti ng o f the a ge nts a t i ssu e he re or 2 sim ilar ch em ic al s w er e as soc ia te d w ith cl ust er s of au toi m m une dis or de rs be lie ve d to 3 be environm entally

induced. He provided a plausib le biolog ical basis for the theory 4 that environm ental toxin s could in duce autoimm une disease by

ref er ring to several 5 oth er stu die s th at

ha d f ound suc h c or

re la tio ns. H e sum

m ar iz ed the c ur re nt k now le dge 6 that benzene and m ercury , two of t he agents at i ssue here, adversely aff ect the hum an 7 im m une sy ste m , a nd h e re vie w ed the stu die s sh ow ing that pr ist an e tr igg ers the 8 fo rm at ionof

lup us- spe ci fi c au toanti bodi es in m ic e. D ah lgr endis cussed a lte rn at ive 9 ex plana tio ns f

or the a sso ci at ion be tween th e ag en ts and P la int if fs ’ auto im

m une 10 dis or de rs , suc h a s ge ne tic sus ce pti bil ity or dr ug- ind uc ed auto im m une dis or de rs , a nd 11 ru le d th em

out

. H av ing pe rf

orm ed his stu dy

c onsi ste nt w iththe Brad for d H ill 12 gui de lin es , D ah lgr enw as the n able to use his ex pe rt j udgm en t t o a sse ss whe the r the 13 associations revea led by his own stud y , the anim al stud i es , an d other pub lished 14 stu die s r eg ar din g c he m ic al e xpos ur e pr ovi de d r el ia bl e supp ort f or a n in fe re nc e of 15 ca usa tio n inhum an s. A ny que sti on r eg ar din g c re dib ili ty of his j udgm en t or 16 interpretation is proper for the trier of fac t to resolve. 17 { 41} When the district court found th at D ahlgren’ s stud y “ fail[ed] to bridge the gap 18 from association to causati o n ,” it im properly blurred the line betwee n the district25

1 co u rt ’s p ro v i n ce t o ev al u at e t h e r el i ab i l i t y o f Da h l g re n ’s m et h o d o l o g y an dt h e ju ry’s 2 pr ov in ce to weig h th e st ren gt h of Dahl gr en ’s con cl us io ns . See A m bros ini , 101 F

. 3d 3 at 141 ( “ By

a tte m pti ng t o e va luate the c re dib ili ty of opp osi ng e xpe rt s and the 4 pe rs ua siv en es s of

c om pe tin g sc ie nti fi c stu die s, the dis tr ic t c ourt c onf la te d th e 5 que sti ons of the adm iss ibi lity of e xpe rt te sti m ony

a nd the w ei ght

appr opr ia te ly

to be 6 ac co rd ed

suc h te sti m ony

by a fact f

ind er . ”)

. I n do ing so, “ the tr ia l c ourt f ai le d to 7 dis tin gui sh b etw ee n th e thr es hol d qu es tio n of a dm iss ibi lity

of e xpe rt te sti m ony

a nd 8 the persuasive weight to be accorded such testim ony by a j ury .” Kennedy v. Collagen 9 Co rp. , 161 F

. 3d 1 226, 12 28 (9th C ir

. 199 8)

. I n Ke nne dy , the c ourt f oc use d onthe 10 m ethodo log y

a n e xpe rt appl ie d to de te rm ine w he the r a m ed ic al pr oduc t wa s c ap ab le 11 of c au sin g auto im

m une dis ea se s and sta te d, “ T he fa ct that a c au se -e ff ec t r el at ion shi p 12 betwee n [the agent] and lupu s in par ticular [had] not been conclus ively established 13 [did] not render [the expert’ s] testim ony inadm issib le.” Id

. a t 12 30. Be ca

use the 14 ex pe rt “ se t f orth the ste ps he took in ar ri vin g at h is c onc lus ionin his de posi tio n” a nd 15 use d “ an al ogi ca l r ea soni ng . . . ba se d onobj ec tiv e, ve ri fi ab le e vid en ce a nd s ci en tif ic 16 m et h o d o l o gy

of the kind traditio nally used by ” experts in his field, the court 17 co nc lud ed

that the pr of

fe re d te sti m ony

w as sup po rt ed

by sc ie nti fi c ev ide nc e an d 18 w oul d a ssi st the tr ie r of f ac t i n w ei ghi ng the e xpe rt ’ s te sti m ony a ga ins t op posi ng26

1 ev id en ce an d i n m ak in g a jud gm en t ab ou t ca us at io n. Id

. a t 12 30- 31. 2 { 42} Inthi s c as e, D ah lgr ensim ilarl y se t f orth t he st ep s he too k ina rr ivi ng at hi s 3 co nc lus ion s. H is r ea soni ng w as ba se d onsc ie nti fi c m et hodo log y of the kin d 4 t ra d i t i o n al l y u s ed b y ex p er t s ad d re s s i n g ca u s at i o n i n t o x i co l o g i ca l ep i d emio l o g y. W e 5 co nc lud e that the m ethodo log y of D ah lgr en ’ s st

udy sup ports a v al id s ci en tif ic 6 inference that is pr obative of causation, even if it does not conclusivelyestablish th at 7 the spe ci fi c ch em ic al s a t iss ue he re , the ag en ts, can ca use lup us o r oth er

auto im m une 8 dis or de rs . A cc or din gly , D ah lgr en ’ s st udy a nd h is c au sa tio n te sti m ony sho uld have 9 be ena dm itt ed

. 10 D. Sum m ary Judgm ent Was Im proper ly Granted 11 { 43} Based on an im proper conclusion that Plaintiffs’ general c ausation evid ence 12 w as ina dm iss ibl e, the dis tr ic t co urt gr an te d part ia l sum m ar y j udgm en t t o D ef

en dants 13 on Pla in ti ffs ’ cl ai m s co nc ern in g lu pu s an d ot he r au to imm un e d is or de rs . Beca us e we 14 re v er s e that determ ination of inadm issib ility , w e re verse the grant of sum m ary 15 j udgm ent as the evidence creates a genuin e issue of m aterial fact th at p re cl udes 16 su m m ary jud gm en t. See Rule 1-056(C). 17 V. CON CLU SION 18 { 44} W e re ve rs e the dis tr ic t c ourt’ s e xc lus ion of Dahlgr en ’ s e xpe rt c au sa tio n27

1 te sti m on y , h is st udy , a nd the a nim al stu die s onw hic h hi s st udy r el ie d. W e al so 2 re ve rs e the sum

m ar y j udgm en t grante d on the ba sis of tho se e xc lus ion s. W e re m an d 3 to the dis tr ic t c ourt f

or pr oc ee din gs c onsi ste nt w iththi s op ini on. 4 { 45} IT IS S O ORDERE D.

5

____ ____ ____ ____ ____ ____ ____ ____ __ 6 CHA RLE S W. DA NIEL S, Justice 7 WE CO NCUR:

8

____ ____ ____ ____ ____ ____ ____ ____ ___ 9 BARBAR

A J. VIGIL, Ch ief Justice

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____ ____ ____ ____ ____ ____ ____ ____ ___ 11 PE TRAJIMEN EZMA ES, Justice

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____ ____ ____ ____ ____ ____ ____ ____ ___ 13 EDWA RD L. CH ÁV EZ , Just ice 14 JUD ITH K. NA KAM UR A, Justice, not p articipating