C. J.). Under the Supremacy Clause, federal law may supersede state law in several different ways. First, when acting within constitutional limits, Congress is empowered to pre-empt state law by so stating in express terms. Jones v. Rath Packing Co., 430 U. S. 519, 525 (1977). In the absence of express pre-emptive language, Congress’ intent to preempt all state law in a particular area may be inferred where the scheme of federal regulation is sufficiently comprehensive to make reasonable the inference that Congress “left no room” for supplementary state regulation. Rice v. Santa Fe Elevator Corp., 331 U. S. 218, 230 (1947). Pre-emption of a whole field also will be inferred where the field is one in which “the federal interest is so dominant that the federal system will be assumed to preclude enforcement of state laws on the same subject.” Ibid.; see Hines v. Davidowitz, 312 U. S. 52 (1941).
Even where Congress has not completely displaced state regulation in a specific area, state law is nullified to the extent that it actually conflicts with federal law. Such a conflict arises when “compliance with both federal and state regulations is a physical impossibility,” Florida Lime & Avocado Growers, Inc. v. Paul, 373 U. S. 132, 142-143 (1963), or when state law “stands as an obstacle to the accomplishment and execution of the full purposes and objectives of Congress,” Hines v. Davidowitz, supra, at 67. See generally Capital Cities Cable, Inc. v. Crisp, 467 U. S. 691, 698-699 (1984).
We have held repeatedly that state laws can be pre-empted by federal regulations as well as by federal statutes. See, e. g., Capital Cities Cable, Inc. v. Crisp, supra, at 699; Fidelity Federal Savings & Loan Assn. v. De la Cuesta, 458 U. S. 141, 153-154 (1982); United States v. Shimer, 367 U. S. 374, 381-383 (1961). Also, for the purposes of the Supremacy Clause, the constitutionality of local ordinances is analyzed in the same way as that of statewide laws. See, e. g., City of Burbank v. Lockheed Air Terminal, Inc., 411 U. S. 624 (1973).