In determining whether a state statute is pre-empted by federal law and therefore invalid under the Supremacy Clause of the Constitution, our sole task is to ascertain the intent of Congress. See "Shaw v. Delta Air Lines, Inc.", 463 U.S. 85, 95, 103 S.Ct. 2890, 2898, 77 L.Ed.2d 490 (1983); "Malone v. White Motor Corp.", 435 U.S. 497, 504, 98 S.Ct. 1185, 1189, 55 L.Ed.2d 443 (1978). 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. E.g., "Jones v. Rath Packing Co.", 430 U.S. 519, 525, 97 S.Ct. 1305, 1309, 51 L.Ed.2d 604 (1977). Second, congressional intent to pre-empt 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, 67 S.Ct. 1146, 1152, 91 L.Ed. 1447 (1947). Neither of these bases for pre-emption exists in this case. Congress has explicitly disclaimed any intent categorically to pre-empt state law or to "occupy the field" of employment discrimination law. See 42 U.S.C. §§ 2000e-7 and 2000h-4.