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Page Number: 2.0

2 

ENTERGY CORP. v. RIVERKEEPER, INC. 

Syllabus 

ductions  in  impingement  and  entrainment,  as  it  had  done  in  its
Phase I rules, in part because the cost of rendering existing facilities
closed-cycle  compliant  would  be  nine  times  the  estimated  cost  of
compliance  with  the  Phase  II  performance  standards,  and  because
other technologies could approach the performance of closed-cycle op-
eration.    The  Phase  II  rules  also  permit  site-specific  variances  from
the national performance standards, provided that the permit-issuing 
authority  imposes  remedial  measures  that  yield  results  “as  close  as
practicable 
standards.” 
§125.94(a)(5)(i),  (ii).   Respondents—environmental  groups  and  vari-
ous  States—challenged  the  Phase  II  regulations.    Concluding  that
cost-benefit analysis is impermissible under 33 U. S. C. §1326(b), the
Second  Circuit  found  the  site-specific  cost-benefit  variance  provision
unlawful  and  remanded  the  regulations  to  the  EPA  for  it  to  clarify
whether it had relied on cost-benefit analysis in setting the national
performance standards.   

performance 

applicable 

the 

to 

Held: The EPA permissibly relied on cost-benefit analysis in setting the
national  performance  standards  and  in  providing  for  cost-benefit
variances  from  those  standards  as  part  of  the  Phase  II  regulations. 
Pp. 7–16.

(a) The  EPA’s  view  that  §1326(b)’s  “best  technology  available  for
minimizing adverse environmental impact” standard permits consid-
eration of the technology’s costs and of the relationship between those
costs and the environmental benefits produced governs if it is a rea-
sonable interpretation of the statute—not necessarily the only possi-
ble  interpretation,  nor  even  the  interpretation  deemed  most  reason-
able  by  the  courts.    Chevron  U. S. A.  Inc.  v.  Natural  Resources 
Defense  Council,  Inc.,  467  U. S.  837,  843–844.    The  Second  Circuit 
took  “best  technology”  to  mean  the  technology  that  achieves  the 
greatest reduction in adverse environmental impacts at a reasonable
cost to the industry, but it may also describe the technology that most 
efficiently  produces  a  good,  even  if  it  produces  a  lesser  quantity  of 
that good than other available technologies.  This reading is not pre-
cluded by the phrase “for minimizing adverse environmental impact.” 
Minimizing admits of degree and is not necessarily used to refer ex-
clusively to the “greatest possible reduction.”  Other Clean Water Act 
provisions show that when Congress wished to mandate the greatest
feasible  reduction  in  water  pollution,  it  used  plain  language,  e.g., 
“elimination  of  discharges  of  all  pollutants,”  §1311(b)(2)(A).    Thus, 
§1326(b)’s use of the less ambitious goal of “minimizing adverse envi-
ronmental impact” suggests that the EPA has some discretion to de-
termine  the  extent  of  reduction warranted  under  the  circumstances, 
plausibly  involving  a  consideration  of  the  benefits  derived  from  re-
ductions and the costs of achieving them.  Pp. 7–9.