P roduction of natural gas and crude oil from shales and other unconventional formations in the United States has expanded significantly due to new technologies such as hydraulic fracturing and horizontal drilling. This boom in production has increased investment in new pipeline infrastructure to gather and transport these resources from producing regions to domestic and foreign consumers. Pipelines represent a relatively safe means of transporting oil and gas as compared to other modes of transportation, but have the potential to cause harm to public health and the environment because of the hazardous materials they carry and the proximity of some pipelines to highly populated areas. Construction of new pipelines and related facilities may prompt congressional interest in the relationship between federal and state authority over siting and safety of pipeline infrastructure. States and localities arguably have an interest in oversight and regulation of pipeline projects within their borders. Such projects could potentially have environmental and safety impacts that could affect their residents. However, the federal government has in the past sought national uniformity in regulation of some aspects of pipeline transportation to provide consumers throughout the United States with access to an adequate supply of oil or gas resources at reasonable prices and to ensure safety and reliability of pipeline infrastructure. This report discusses the relationship between federal and state authority over siting and safety of crude oil and natural gas transmission and gathering pipelines and related facilities. The report does not examine authority over other modes of transportation such as rail, truck, or vessel transport. Nor does it examine in detail oil spill response or liability laws; underground storage of natural gas; or the relationship between federal and tribal authority over pipelines that cross Indian lands. Authorization for "siting" of a pipeline facility generally involves approval of the route and location of the pipeline and related facilities (e.g., compressor stations that push natural gas through pipelines). Notably, siting of interstate natural gas transmission pipelines involves a centralized federal approval process overseen by the Federal Energy Regulatory Commission (FERC), while siting of interstate crude oil transmission pipelines typically involves a state-by-state approval process. Commentators that have studied regulatory treatment of natural gas and crude oil pipelines have pointed to various reasons for these differences, including the fact that most natural gas is transported over land by pipeline because of the prohibitive cost of converting it into liquefied natural gas (LNG) in large volumes for transport by other modes; the political and economic background of the regulatory regime for each resource; and "varying concerns over monopoly power," among other things. This section also addresses federal and state laws that contain additional requirements for construction or operation of an oil or gas pipeline. Siting, construction, and operation of interstate natural gas pipelines require specific approval from the federal government. Section 7(c) of the Natural Gas Act of 1938 (NGA) provides that a person seeking to construct, extend, acquire, or operate a facility for the transportation or wholesale sale of natural gas in interstate commerce must obtain from FERC a certificate of public convenience and necessity authorizing these actions. Generally, under the NGA, FERC may issue such certificates only after notice, a hearing, and a determination that (1) the applicant is willing and able to provide the service; (2) the applicant will comply with the NGA and FERC rules promulgated thereunder; and (3) the action will be "required by the present or future public convenience and necessity." Although an entity seeking to build an inter state natural gas pipeline must seek FERC's approval, the agency's siting jurisdiction under the NGA does not extend to intra state pipelines (i.e., pipelines not engaged in interstate commerce) or pipeline facilities used for the production, gathering, or local distribution of natural gas. However, as discussed below, states may have specific siting requirements for some pipelines not within FERC's jurisdiction. The Supreme Court has held that Congress's enactment of the NGA demonstrated legislative intent to "occupy the field" with respect to transportation and wholesale sale of natural gas in interstate commerce to the exclusion of state and local regulation. This holding suggests that, as an initial matter, an entity holding a certificate of public convenience and necessity from FERC is not subject to state or local laws (e.g., zoning laws) that have more than an incidental effect on construction of the certificated facilities for transportation of natural gas in interstate commerce. However, the NGA allows FERC to require a certificate holder to comply with state or local laws as a condition of exercising rights under the certificate. In the past, FERC has apparently taken the view that state or local laws that affect siting of an interstate natural gas pipeline facility might not be preempted unless they conflict with FERC's exercise of its jurisdiction under federal law or would pose an obstacle to the facility's construction. As discussed further below, the NGA also contains a savings clause preserving states' "rights" under three federal laws: the Coastal Zone Management Act (CZMA), Clean Air Act (CAA), and Clean Water Act (CWA). Federal laws and regulations also provide several avenues for a state to provide input into FERC's siting review of an interstate natural gas pipeline. For example, a state agency may provide input to FERC as an intervenor (i.e., an official party to the proceedings) during the certificate application proceedings, or during an environmental review FERC conducts under the National Environmental Policy Act (NEPA) in connection with the certificate proceedings. States that participated in the certificate proceeding may seek rehearing within 30 days after FERC issues an order granting a certificate. Following a rehearing, a state could seek judicial review of FERC's order in the appropriate federal court of appeals. The NGA, as amended by the Energy Policy Act of 2005 (EPAct), also contains procedures for judicial review of actions and omissions by FERC and other federal and state agencies under federal law pertaining to grant of a certificate. As noted above, the NGA specifically provides that it does not preempt state "rights" under three federal laws under which the federal government may delegate authority to the states or encourage federal/state cooperation: the CZMA, the CAA, and the CWA. This provision may preserve state regulatory authority when, for example, a state law affecting construction or operation of a pipeline project has been incorporated by reference into a federally approved state implementation plan (SIP) under the CAA or when a state regulates a pipeline's construction consistent with a federally approved coastal management plan. However, the NGA provides an additional check on state authority under these laws by vesting federal courts of appeals with original and exclusive jurisdiction over civil suits seeking judicial review of federal or state actions or omissions concerning issuance, denial, or conditioning of a permit or other approval under federal law when it would interfere with construction of a FERC-certificated facility (e.g., CAA pre-construction permits or CWA water quality certifications). This provision for judicial review does not apply with respect to the CZMA, which contains its own administrative review process administered by the Secretary of Commerce. If the court determines the actions or omissions are inconsistent with federal law governing issuance of the permit and would prevent construction of an interstate pipeline, it must remand the proceeding to the relevant federal or state agency for further action consistent with its order, to be undertaken prior to a court-imposed deadline. It is important to note that the CAA and CWA authorize the Environmental Protection Agency (EPA) to exercise continuing oversight over a state's administration and enforcement of federal environmental law permitting programs relevant to pipeline siting. Section 313(b) of EPAct designated FERC as the lead agency for coordinating NEPA reviews and required federal approvals for interstate natural gas pipeline certificate applications. Such federal approvals include those issued by a state under delegated federal authority (e.g., state issuance of permits under a federal environmental law like the CWA). EPAct also directed FERC to establish a schedule for completion of federal authorizations needed for the agency to grant a pipeline certificate, consistent with time periods established in other federal laws. Pursuant to this authority, FERC promulgated a rule requiring that, in general, federal and state agencies determine whether to issue a permit or other approval needed under federal law within 90 days of FERC issuing its final "environmental document." The NGA, as amended, provides judicial remedies for an applicant in a federal court of appeals if a federal or state agency does not meet a time frame set by the Commission. Critics have argued that this remedy is ineffective to prevent agencies from exceeding the 90-day deadline. Section 7(h) of the NGA delegates the federal power of eminent domain to a holder of a certificate of public convenience and necessity. The holder may exercise this power, consistent with the terms of the certificate, in federal or state court to acquire a private right-of-way (ROW), land, or other property interest needed to build, operate, or maintain an interstate pipeline or related facility if it cannot obtain the necessary interests by contract or negotiation with a property owner. Generally, "gathering lines" are pipelines that transport oil or gas from a production well to a processing facility or transmission pipeline. The Pipeline and Hazardous Materials Safety Administration (PHMSA) within the Department of Transportation (DOT) has noted that some shale gas gathering lines "are generally of much larger diameter and operating at higher pressure than traditional rural gas gathering lines, increasing the concern for safety of the environment and people near operations." As discussed above, FERC's siting jurisdiction under the NGA does not extend to facilities or pipelines used for the gathering of natural gas. However, the NGA does not define "gathering line." FERC has developed a test to determine when a pipeline is a nonjurisdictional gathering line. A 2010 FERC order illustrates how the agency may evaluate whether natural gas pipelines are "gathering lines" exempt from its jurisdiction under the NGA.