Document ID: ./input/supremecourt_opinions/opinions/21pdf/20-1530_n758.pdf
Page Number: 62

6 

WEST VIRGINIA v. EPA 

KAGAN, J., dissenting 

regulating emissions from categories of stationary sources 
deemed to contribute significantly to pollution.  As applied 
to existing (not new) sources, the program mandates—via
Section  111(d)—that  EPA  set  emissions  levels  for  pollu-
tants not covered by the NAAQS or HAP programs, includ-
ing carbon dioxide.

Section 111(d) thus ensures that EPA regulates existing 
power plants’ emissions of all pollutants.  When the pollu-
tant  at  issue  falls  within  the  NAAQS  or  HAP  programs, 
EPA need do no more.  But when the pollutant falls outside
those programs, Section 111(d) requires EPA to set an emis-
sions level for currently operating power plants (and other 
stationary sources).  That means no pollutant from such a
source can go unregulated: As the Senate Report explained, 
Section 111(d) guarantees that “there should be no gaps in 
control activities pertaining to stationary source emissions 
that  pose  any  significant  danger  to  public  health  or  wel-
fare.”  S.  Rep.  No.  91–1196,  p. 20  (1970).    Reflecting  that 
language,  the  majority  calls  Section  111(d)  a  “gap-filler.” 
Ante,  at  5.    It  might  also  be  thought  of  as  a  backstop  or 
catch-all  provision,  protecting  against  pollutants  that  the 
NAAQS  and  HAP  programs  let  go  by.    But  the  section  is 
not, as the majority further claims, an “ancillary provision” 
or a statutory “backwater.”  Ante, at 20, 26.  That charac-
terization is a non-sequitur.  That something is a backstop 
does not make it a backwater.  Even if they are needed only 
infrequently,  see  ante,  at  6,  20,  backstops  can  perform  a 
critical function—and this one surely does.  Again, Section
111(d) tells EPA that when a pollutant—like carbon diox-
ide—is  not  regulated  through  other  programs,  EPA  must 
undertake  a  further  regulatory  effort  to  control  that  sub-
stance’s emission from existing stationary sources.  In that 
way, Section 111(d) operates to ensure that the Act achieves
comprehensive pollution control.

Section 111 describes the prescribed regulatory effort in
expansive  terms.  EPA  must  set  for  the  relevant  source