Document ID: ./input/supremecourt_opinions/opinions/21pdf/20-1530_n758.pdf
Page Number: 12

6 

WEST VIRGINIA v. EPA 

Opinion of the Court 

Although the States set the actual rules governing exist-
ing power plants, EPA itself still retains the primary regu-
latory role in Section 111(d).  The Agency, not the States, 
decides  the  amount  of  pollution  reduction  that  must  ulti-
mately  be  achieved.    It  does  so  by  again  determining,  as
when setting the new source rules, “the best system of emis-
sion reduction . . . that has been adequately demonstrated 
for [existing covered] facilities.”  40 CFR §60.22(b)(5) (2021); 
see also 80 Fed. Reg. 64664, and n. 1.  The States then sub-
mit  plans  containing  the  emissions  restrictions  that  they
intend to adopt and enforce in order not to exceed the per-
missible level of pollution established by EPA.  See §§60.23, 
60.24; 42 U. S. C. §7411(d)(1).

Reflecting the ancillary nature of Section 111(d), EPA has
used it only a handful of times since the enactment of the 
statute in 1970.  See 80 Fed. Reg. 64703, and n. 275 (past 
regulations  pertained  to  “four  pollutants  from  five  source
categories”).  For  instance,  the  Agency  has  established 
emissions limits on acid mist from sulfuric acid production, 
41 Fed. Reg. 48706 (1976) (identifying “fiber mist elimina-
tor”  technology  as  BSER);  sulfide  gases  released  by  kraft 
pulp mills, 44 Fed. Reg. 29829 (1979) (determining BSER 
to  be  a  combination  of  scrubbers,  incineration,  filtration 
systems, and temperature control); and emissions of vari-
ous  harmful  gases  from  municipal  landfills,  61  Fed.  Reg. 
9907 (1996) (setting BSER as use of a flare to combust the 
gases).  It was thus only a slight overstatement for one of 
the architects of the 1990 amendments to the Clean Air Act 
to refer to Section 111(d) as an “obscure, never-used section 
of the law.”  Hearings on S. 300 et al. before the Subcom-
mittee on Environmental Protection of the Senate Commit-
tee  on  Environment  and  Public  Works,  100th  Cong.,  1st 
Sess., 13 (1987) (remarks of Sen. Durenberger). 

B 
Things changed in October 2015, when EPA promulgated