Document ID: ./input/supremecourt_opinions/opinions/08pdf/07-588.pdf/07-588.pdf
Page Number: 18

Cite as:  556 U. S. ____ (2009) 

15 

Opinion of the Court 

portionate”  standard  may  be  somewhat  different  from  its 
current  “significantly  greater  than”  standard,  there  is 
nothing in the statute that would indicate that the former
is a permissible interpretation while the latter is not. 

Indeed,  in  its  review  of  the  EPA’s  Phase  I  regulations, 
the  Second  Circuit  seemed  to  recognize  that  §1326(b)
permits some form of cost-benefit analysis.  In considering
a  challenge  to  the  EPA’s  rejection  of  dry  cooling  systems7 
as the “best technology available” for Phase I facilities the 
Second  Circuit  noted  that  “while  it  certainly  sounds  sub-
stantial that dry cooling is 95 percent more effective than
closed-cycle  cooling,  it  is  undeniably  relevant  that  that
difference represents a relatively small improvement over 
cost.” 
closed-cycle 
Riverkeeper, 358 F. 3d, at 194, n. 22.  And in the decision 
below  rejecting  the  use  of  cost-benefit  analysis  in  the
Phase  II  regulations,  the  Second  Circuit  nonetheless 
interpreted “best technology available” as mandating only 
those  technologies  that  can  “be  reasonably  borne  by  the
industry.”  475 F. 3d, at 99.  But whether it is “reasonable” 
to bear a particular cost may well depend on the resulting
benefits;  if  the  only  relevant  factor  was  the  feasibility  of 
the costs, their reasonableness would be irrelevant. 

cooling  at  a  very 

significant 

In the last analysis, even respondents ultimately recog-
nize that some form of cost-benefit analysis is permissible. 
They  acknowledge  that  the  statute’s  language  is  “plainly 
not  so  constricted  as  to  require  EPA  to  require  industry
petitioners  to  spend  billions  to  save  one  more  fish  or 
plankton.”    Brief  for  Respondents  Riverkeeper,  Inc.  et al. 
29.  This  concedes  the  principle—the  permissibility  of  at
least some cost-benefit analysis—and we see no statutory 
basis  for  limiting  its  use  to  situations  where  the  benefits 

—————— 

7 Dry  cooling  systems  use  air  drafts  to  remove  heat,  and  accordingly 
remove little or no water from surrounding water sources.  See 66 Fed. 
Reg. 65282 (2001).