“ Employees' message is plain: the power to regulate commerce includes the power to override States' immunity from suit, but we will not conclude that Congress has overridden this immunity unless it does so clearly.
Since Employees, we have twice assumed that Congress has the authority to abrogate States' immunity when acting pursuant to the Commerce Clause. ”

“ As a practical matter, however, it is difficult to imagine that a State could forbid the disposal of all wastes. Hence, the Commerce Clause as interpreted in Philadelphia v. New Jersey ensures that we often must look to the Federal Government for environmental solutions. And often those solutions, to be satisfactory, must include a cause of action for money damages.
The cause of action under consideration, for example, came about only after Congress had tried to solve the problem posed by hazardous substances through other means. ”

“ Moreover, in many situations, it is only money damages that will effectuate Congress' legitimate Commerce Clause objectives. Here, for example, after failing to solve the hazardous-substances problem through preventive measures, Congress chose to extend liability to everyone potentially responsible for contamination, and, because of the enormous costs of cleanups and the finite nature of Government resources, sought to encourage private parties to help out by allowing them to recover for their own cleanup efforts. ”

“ The remedy that Congress felt it needed in CERCLA is sweeping: everyone who is potentially responsible for hazardous-waste contamination may be forced to contribute to the costs of cleanup. See, e.g., 42 U.S.C. § 9613 (f) (1) (1986 ed., Supp. IV) . Congress did not think it enough, moreover, to permit only the Federal Government to recoup the costs of its own cleanups of hazardous-waste sites; the Government's resources being finite, it could neither pay up front for all necessary cleanups nor undertake many different projects at the same time. ”

“ There is no merit to Pennsylvania's contention that the allowance of damages suits by private citizens against unconsenting States impermissibly expands the jurisdiction of federal courts beyond the bounds of Article III, since, by ratifying the Constitution containing the Commerce Clause, the States consented to suits against them based on congressionally created causes of action. ”

“ This section is, needless to say, an explicit recognition of the potential liability of States under this statute; Congress need not exempt States from liability unless they would otherwise be liable. Similarly, unless suits against the States were elsewhere permitted, Congress would have had no reason to specify that citizen suits-as opposed to the kind of lawsuit involved here could be brought "against any person (including the United States and any other governmental instrumentality or agency, to the extent permitted by the eleventh amendment to the Constitution) ." ”

“ Pennsylvania's arguments to the contrary are not persuasive. If accepted, the contention that CERCLA creates state liability only to the Federal Government would render meaningless the § 101 (20) (D) language making States liable "to the same extent . . . as any nongovernmental entity, including liability for [damages] ," since no explicit authorization is necessary before the Federal Government may sue a State for damages. ”

“ Nor can she deny to the general government the right to exercise all its granted powers, though they may interfere with the full enjoyment of rights she would have if those powers had not been thus granted. ”

“ The statute's plain language authorizes such suits. Section 101 (21) 's express inclusion of States within its definition of "persons," and § 101 (20) (D) 's plain statement that state and local governments are to be considered "owners or operators" in all but very narrow circumstances, together establish that Congress intended that States be liable for cleanup costs under § 107 along with everyone else responsible for creating hazardous waste sites. ”

“ Working together, Pennsylvania and the Federal Government cleaned up the area, and the Federal Government reimbursed the State for cleanup costs of $720,000.
To recoup these costs, the United States sued Union Gas under §§ 104 and 106 of CERCLA, 42 U.S.C. §§ 9604 and 9606, claiming that Union Gas was liable for such costs because the company and its predecessors had deposited coal tar into the ground near Brodhead Creek. ”

“ IV) , and imposes the costs of the cleanup on those responsible for the contamination, § 9607. Two general terms, among others, describe those who may be liable under CERCLA for the costs of remedial action: "persons" and "owners or operators." § 9607 (a) . "States" are explicitly included within the statute's definition of "persons." § 9601 (21) . The term "owner or operator" is defined by reference to certain activities that a "person" may undertake. ”