Document ID: ./input/supremecourt_opinions/opinions/21pdf/21-404_i5ea.pdf
Page Number: 6.0

Cite as:  596 U. S. ____ (2022) 

3 

Opinion of the Court 

employs directly.  See 40 U. S. C. §3172(c).

As compared to the general state workers’ compensation
regime, Washington’s law makes it easier for federal con-
tract workers at Hanford to establish their entitlement to 
workers’ compensation.  In particular, the statute creates a
causal presumption that certain diseases and illnesses are 
caused  by  the  cleanup  work  at  Hanford.    See  Wash.  Rev. 
Code §§51.32.187(2), (3), (4).  The presumption is rebuttable
only  by  clear  and  convincing  evidence.  §51.32.187(2)(b).
And the presumption lasts for a worker’s entire life, even 
after the worker’s time at Hanford ends.  §51.32.187(5)(a). 
Because the Federal Government pays workers’ compensa-
tion claims for federal contractors at Hanford, see App. 48–
50,  Washington’s  law  increases  workers’  compensation 
costs for the Federal Government. 

The United States brought suit against Washington, ar-
guing  that  its  law  violated  the  Supremacy  Clause  by  dis-
criminating against the Federal Government.  The District 
Court concluded that the state law fell within the scope of
the  federal  waiver  of  immunity  contained  in  40  U. S. C. 
§3172 and was therefore constitutional.  The Ninth Circuit 
affirmed.  See 994 F. 3d 994, 1012 (2020).  We granted cer-
tiorari  to  determine  the  constitutionality  of  Washington’s
law. 

II 
Washington first claims that this case is moot.  After we 
granted certiorari, Washington enacted a new statute, see 
S.  5890,  67th  Leg.,  Reg.  Sess.  (2022),  which  changed  the 
scope of the original law.  The law’s causal presumption no
longer  applies  exclusively  to  Hanford  site  workers  who
“work, either directly or indirectly, for the United States.”
§51.32.187(1)(b).  Instead, under the new law, the presump-
tion applies more broadly to any “worker working at a radi-
ological hazardous waste facility.”  2022 Wash. Sess. Laws