Document ID: ./input/supremecourt_opinions/opinions/21pdf/20-1530_n758.pdf
Page Number: 10.0

4 

WEST VIRGINIA v. EPA 

Opinion of the Court 

words, EPA must directly require all covered sources to re-
duce their emissions to a certain level.  And it chooses that 
level by determining the “maximum degree of reduction” it 
considers “achievable” in practice by using the best existing
technologies and methods.  §7412(d)(3). 

Thus, in the parlance of environmental law, Section 112
directs the Agency to impose “technology-based standard[s]
for  hazardous  emissions,”  Alaska  Dept.  of  Environmental 
Conservation v. EPA, 540 U. S. 461, 485, n. 12 (2004) (em-
phasis added).  This sort of “ ‘technology-based’ approach fo-
cuses upon the control technologies that are available to in-
dustrial  entities  and  requires  the  agency  to  . . .  ensur[e]
that regulated firms adopt the appropriate cleanup technol-
ogy.”  T.  McGarity,  Media-Quality,  Technology,  and  Cost-
Benefit Balancing Strategies for Health and Environmen-
tal Regulation, 46 Law & Contemp. Prob. 159, 160 (Summer 
1983)  (McGarity).  (Such  “technologies”  are  not  limited  to
literal technology, such as scrubbers; “changes in the design 
and operation” of the facility, or “in the way that employees 
perform their tasks,” are also available options.  Id., at 163, 
n. 18.)

The third air pollution control scheme is the New Source
Performance  Standards  program  of  Section  111.  §7411.
That  section  directs  EPA  to  list  “categories  of  stationary
sources” that it determines “cause[], or contribute[ ] signifi-
cantly to, air pollution which may reasonably be anticipated 
to endanger public health or welfare.”  §7411(b)(1)(A).  Un-
der  Section  111(b),  the  Agency  must  then  promulgate  for 
each  category  “Federal  standards  of  performance  for  new
sources,”  §7411(b)(1)(B).  A  “standard  of  performance”  is
one that 

“reflects  the  degree  of  emission  limitation  achievable
through the application of the best system of emission 
reduction which (taking into account the cost of achiev-
ing such reduction and any nonair quality health and