opinion: Per Curiam.
  The Secretary of Labor is authorized to inspect work sites to uncover noncompliance with the Occupational Safety and Health Act. 29 U. S. C. § 657(a). If, as a result of such an inspection, the Secretary discovers a violation of the Act, he is authorized to issue a citation to the employer fixing a reasonable time for the abatement of the violation, § 658(a), and assessing a penalty for the violation. § 666. The employer then has 15 days in which to contest the citation. § 659(a). Similarly, employees have 15 days in which to challenge as unreasonable “the period of time fixed in the citation for the abatement of the violation.” § 659(c). See generally Whirlpool Corp. v. Marshall, 445 U. S. 1, 9, n. 11 (1980). The statute and rules of the Occupational Safety and Health Review Commission also permit affected employees to participate as parties in any hearing in which the employer contests the citation. 29 U. S. C. § 659(c); 29 CFR § 2200.20(a) (1985).
  If an employer contests the citation, and the Secretary intends to seek its enforcement, the Secretary must file a complaint with the Commission within 20 days, and the employer must file an answer within 15 days. 29 CFR § 2200.33 (1985). Once these pleadings are filed, a hearing to determine the validity of the citation will be held before an administrative law judge (ALJ), with discretionary review by the Commission. 29 U. S. C. §§ 659(c), 661(j).
  In the present cases, the Secretary cited Cuyahoga Valley Railway Company for a violation of the Act. Cuyahoga contested the citation, the Secretary filed a complaint with the Commission, and Cuyahoga filed an answer. Respondent United Transportation Union, which represents Cuyahoga employees, properly moved to intervene in the proceedings. At the hearing, however, the Secretary moved to vacate the citation on the ground that the Federal Railway Administration, not the Secretary, had jurisdiction over the relevant safety conditions. Despite the Union’s objection, the ALJ granted the Secretary’s motion and vacated the citation. Thereafter, the Commission directed review of the ALJ’s order. The Secretary promptly objected to this action, asserting that part of the citation involved matters beyond the reach of the Act and that additional portions of the citation did not warrant litigation because of the state of the evidence. He also stated that the record before the Commission was inadequate to resolve the issue posed. Some six years later, the Commission rejected this submission and remanded the case to the ALJ for consideration of the Union’s objections.
  The Court of Appeals for the Sixth Circuit affirmed the Commission’s holding that it could review the Secretary’s decision to withdraw a citation. Donovan v. United Transportation Union, 748 F. 2d 340 (1984). The court recognized that the Secretary “has the sole authority to determine whether to prosecute” a violation of the Act. Id., at 343. Here, however, the court found that the Secretary “had already made the decision to prosecute by filing a complaint and that complaint had been answered at the time the Secretary attempted to withdraw the citation.” Ibid. Because the “adversarial process was well-advanced at the time the Secretary attempted to withdraw the citation,” the court reasoned that the Commission, “as the adjudicative body, had control of the case and the authority to review the Secretary’s withdrawal of the citation.” Ibid.
  Contrary to the Sixth Circuit’s decision, eight other Courts of Appeals have held that the Secretary has unreviewable discretion to withdraw a citation charging an employer with violating the Occupational Health and Safety Act. Donovan v. Allied Industrial Workers (Midland), 760 F. 2d 783, 785 (CA7 1985); Donovan v. Local 962, International Chemical Workers Union (Englehard), 748 F. 2d 1470, 1473 (CA11, 1984); Donovan v. International Union, Allied Industrial Workers (Whirlpool), 722 F. 2d 1415, 1422 (CA8 1983); Donovan v. United Steelworkers of America (Monsanto), 722 F. 2d 1158, 1160 (CA4 1983); Donovan v. Oil, Chemical and Atomic Workers International (American Petrofina), 718 F. 2d 1341, 1352-1353 (CA5 1983), cert. denied, 466 U. S. 971 (1984); Donovan v. Occupational Safety and Health Review Comm’n (Mobil Oil), 713 F. 2d 918, 926-927 (CA2 1983); Oil, Chemical and Atomic Workers International v. Occupational Safety and Health Comm’n (American Cynamid), 217 U. S. App. D. C. 137, 144-145, 671 F. 2d 643, 650-651, cert. denied, 459 U. S. 905 (1982); Marshall v. Sun Petroleum Products Co., 622 F. 2d 1176, 1187 (CA3), cert. denied, 449 U. S. 1061 (1980). We agree with the decisions of these courts.
  It is apparent that the Court of Appeals’ decision is inconsistent with the detailed statutory scheme which contemplates that the rights created by the Act are to be protected by the Secretary. See Atlas Roofing Co. v. Occupational Safety and Health Comm’n, 430 U. S. 442, 444-447 (1977); Mobil Oil, supra, at 927; Sun Petroleum Products, supra, at 1187. It is also clear that enforcement of the Act is the sole responsibility of the Secretary. Oil, Chemical and Atomic Workers International v. Occupational Safety and Health Comm’n, supra, at 143, 671 F. 2d, at 649. It is the Secretary, not the Commission, who sets the substantive standards for the workplace, and only the Secretary has the authority to determine if a citation should be issued to an employer for unsafe working conditions, 29 U. S. C. §658. A necessary adjunct of that power is the authority to withdraw a citation and enter into settlement discussions with the employer. Whirlpool, supra, at 1420; Mobil Oil, supra, at 927. The Commission’s function is to act as a neutral arbiter and determine whether the Secretary’s citations should be enforced over employee or union objections. Its authority plainly does not extend to overturning the Secretary’s decision not to issue or to withdraw a citation.
  The Sixth Circuit’s conclusion that the Commission can review the Secretary’s decision to withdraw a citation would discourage the Secretary from seeking voluntary settlements with employers in violation of the Act, thus unduly hampering the enforcement of the Act. Whirlpool, supra, at 1420; Mobil Oil, supra, at 927. Such a procedure would also allow the Commission to make both prosecutorial decisions and to serve as the adjudicator of the dispute, a commingling of roles that Congress did not intend. Whirlpool, supra, at 1419; Mobil Oil, supra, at 930-931; Sun Petroleum Products, supra, at 1187. Indeed, the Commission itself was created to avoid giving the Secretary both prosecutorial and adjudicatory powers. See generally Senate Committee on Labor and Public Welfare, Subcommittee on Labor, 92d Cong., 1st Sess., Legislative History of the Occupational Safety and Health Act of 1970 (S. 2193, Pub. L. 91-596) (Comm. Print 1971). Accord, Whirlpool, supra, at 1419; Mobil Oil, supra, at 930-931, and n. 21. The other Courts of Appeals to address this problem have recognized the distinct roles of the Secretary and the Commission and accordingly have acknowledged that the Secretary’s decision to withdraw a citation against an employer under the Act is not reviewable by the Commission. Based on these considerations, the petitions for certiorari are granted, and the judgment of the Court of Appeals is
  Reversed.
  Justice Brennan and Justice Blackmun dissent from summary disposition. They would grant certiorari and set the cases for oral argument.
  Justice Marshall dissents from this summary disposition, which has been ordered without affording the parties prior notice or an opportunity to file briefs on the merits. See Maggio v. Fulford, 462 U. S. 111, 120-121 (1983) (Marshall, J., dissenting); Wyrick v. Fields, 459 U. S. 42, 51-52 (1982) (Marshall, J., dissenting).
  Vacating the citation thus did not rest solely on jurisdictional grounds. Nor did the Court of Appeals’ decision sustaining the Commission’s order focus on jurisdiction. Its holding would permit review by the Commission of the Secretary’s withdrawal of any citation, whatever the reason, provided the adversarial process was sufficiently advanced to vest control in the Commission. For these reasons and because the issue relates to the statutory division of authority between the Secretary and the Commission, rather than the question of judicial review of administrative action, the cases do not pose the question whether an agency’s decision, resting on jurisdictional concerns, not to take enforcement action is presumptively immune from judicial review under the Administrative Procedure Act, 5 U. S. C. § 701(a)(2). See Heckler v. Chaney, 470 U. S. 821, 833, n. 4 (1985).
  The Court of Appeals also relied to some extent on the position of the Commission as to the scope of its powers. The Commission, however, has since revised its view and now declines to review the Secretary’s dismissal of a citation. Pan American World Airways, Inc., 1984 OSHD ¶26,920; American Bakeries Co., 1984 OSHD ¶26,951; Copperweld Steel Co., 1984 OSHD ¶ 26,956.
choices: attorney general of the United States, or his office specified state board or department of education city, town, township, village, or borough government or governmental unit state commission, board, committee, or authority county government or county governmental unit, except school district court or judicial district state department or agency governmental employee or job applicant female governmental employee or job applicant minority governmental employee or job applicant minority female governmental employee or job applicant not listed among agencies in the first Administrative Action variable retired or former governmental employee U.S. House of Representatives interstate compact judge state legislature, house, or committee local governmental unit other than a county, city, town, township, village, or borough governmental official, or an official of an agency established under an interstate compact state or U.S. supreme court local school district or board of education U.S. Senate U.S. senator foreign nation or instrumentality state or local governmental taxpayer, or executor of the estate of state college or university United States State person accused, indicted, or suspected of crime advertising business or agency agent, fiduciary, trustee, or executor airplane manufacturer, or manufacturer of parts of airplanes airline distributor, importer, or exporter of alcoholic beverages alien, person subject to a denaturalization proceeding, or one whose citizenship is revoked American Medical Association National Railroad Passenger Corp. amusement establishment, or recreational facility arrested person, or pretrial detainee attorney, or person acting as such;includes bar applicant or law student, or law firm or bar association author, copyright holder bank, savings and loan, credit union, investment company bankrupt person or business, or business in reorganization establishment serving liquor by the glass, or package liquor store water transportation, stevedore bookstore, newsstand, printer, bindery, purveyor or distributor of books or magazines brewery, distillery broker, stock exchange, investment or securities firm construction industry bus or motorized passenger transportation vehicle business, corporation buyer, purchaser cable TV car dealer person convicted of crime tangible property, other than real estate, including contraband chemical company child, children, including adopted or illegitimate religious organization, institution, or person private club or facility coal company or coal mine operator computer business or manufacturer, hardware or software consumer, consumer organization creditor, including institution appearing as such; e.g., a finance company person allegedly criminally insane or mentally incompetent to stand trial defendant debtor real estate developer disabled person or disability benefit claimant distributor person subject to selective service, including conscientious objector drug manufacturer druggist, pharmacist, pharmacy employee, or job applicant, including beneficiaries of employer-employee trust agreement, employee health and welfare fund, or multi-employer pension plan electric equipment manufacturer electric or hydroelectric power utility, power cooperative, or gas and electric company eleemosynary institution or person environmental organization employer. If employer's relations with employees are governed by the nature of the employer's business (e.g., railroad, boat), rather than labor law generally, the more specific designation is used in place of Employer. farmer, farm worker, or farm organization father female employee or job applicant female movie, play, pictorial representation, theatrical production, actor, or exhibitor or distributor of fisherman or fishing company food, meat packing, or processing company, stockyard foreign (non-American) nongovernmental entity franchiser franchisee lesbian, gay, bisexual, transexual person or organization person who guarantees another's obligations handicapped individual, or organization of devoted to health organization or person, nursing home, medical clinic or laboratory, chiropractor heir, or beneficiary, or person so claiming to be hospital, medical center husband, or ex-husband involuntarily committed mental patient Indian, including Indian tribe or nation insurance company, or surety inventor, patent assigner, trademark owner or holder investor injured person or legal entity, nonphysically and non-employment related juvenile government contractor holder of a license or permit, or applicant therefor magazine male medical or Medicaid claimant medical supply or manufacturing co. racial or ethnic minority employee or job applicant minority female employee or job applicant manufacturer management, executive officer, or director, of business entity military personnel, or dependent of, including reservist mining company or miner, excluding coal, oil, or pipeline company mother auto manufacturer newspaper, newsletter, journal of opinion, news service radio and television network, except cable tv nonprofit organization or business nonresident nuclear power plant or facility owner, landlord, or claimant to ownership, fee interest, or possession of land as well as chattels shareholders to whom a tender offer is made tender offer oil company, or natural gas producer elderly person, or organization dedicated to the elderly out of state noncriminal defendant political action committee parent or parents parking lot or service patient of a health professional telephone, telecommunications, or telegraph company physician, MD or DO, dentist, or medical society public interest organization physically injured person, including wrongful death, who is not an employee pipe line company package, luggage, container political candidate, activist, committee, party, party member, organization, or elected official indigent, needy, welfare recipient indigent defendant private person prisoner, inmate of penal institution professional organization, business, or person probationer, or parolee protester, demonstrator, picketer or pamphleteer (non-employment related), or non-indigent loiterer public utility publisher, publishing company radio station racial or ethnic minority person or organization protesting racial or ethnic segregation or discrimination racial or ethnic minority student or applicant for admission to an educational institution realtor journalist, columnist, member of the news media resident restaurant, food vendor retarded person, or mental incompetent retired or former employee railroad private school, college, or university seller or vendor shipper, including importer and exporter shopping center, mall spouse, or former spouse stockholder, shareholder, or bondholder retail business or outlet student, or applicant for admission to an educational institution taxpayer or executor of taxpayer's estate, federal only tenant or lessee theater, studio forest products, lumber, or logging company person traveling or wishing to travel abroad, or overseas travel agent trucking company, or motor carrier television station union member unemployed person or unemployment compensation applicant or claimant union, labor organization, or official of veteran voter, prospective voter, elector, or a nonelective official seeking reapportionment or redistricting of legislative districts (POL) wholesale trade wife, or ex-wife witness, or person under subpoena network slave slave-owner bank of the united states timber company u.s. job applicants or employees Army and Air Force Exchange Service Atomic Energy Commission Secretary or administrative unit or personnel of the U.S. Air Force Department or Secretary of Agriculture Alien Property Custodian Secretary or administrative unit or personnel of the U.S. Army Board of Immigration Appeals Bureau of Indian Affairs Bonneville Power Administration Benefits Review Board Civil Aeronautics Board Bureau of the Census Central Intelligence Agency Commodity Futures Trading Commission Department or Secretary of Commerce Comptroller of Currency Consumer Product Safety Commission Civil Rights Commission Civil Service Commission, U.S. Customs Service or Commissioner of Customs Defense Base Closure and REalignment Commission Drug Enforcement Agency Department or Secretary of Defense (and Department or Secretary of War) Department or Secretary of Energy Department or Secretary of the Interior Department of Justice or Attorney General Department or Secretary of State Department or Secretary of Transportation Department or Secretary of Education U.S. Employees' Compensation Commission, or Commissioner Equal Employment Opportunity Commission Environmental Protection Agency or Administrator Federal Aviation Agency or Administration Federal Bureau of Investigation or Director Federal Bureau of Prisons Farm Credit Administration Federal Communications Commission (including a predecessor, Federal Radio Commission) Federal Credit Union Administration Food and Drug Administration Federal Deposit Insurance Corporation Federal Energy Administration Federal Election Commission Federal Energy Regulatory Commission Federal Housing Administration Federal Home Loan Bank Board Federal Labor Relations Authority Federal Maritime Board Federal Maritime Commission Farmers Home Administration Federal Parole Board Federal Power Commission Federal Railroad Administration Federal Reserve Board of Governors Federal Reserve System Federal Savings and Loan Insurance Corporation Federal Trade Commission Federal Works Administration, or Administrator General Accounting Office Comptroller General General Services Administration Department or Secretary of Health, Education and Welfare Department or Secretary of Health and Human Services Department or Secretary of Housing and Urban Development Interstate Commerce Commission Indian Claims Commission Immigration and Naturalization Service, or Director of, or District Director of, or Immigration and Naturalization Enforcement Internal Revenue Service, Collector, Commissioner, or District Director of Information Security Oversight Office Department or Secretary of Labor Loyalty Review Board Legal Services Corporation Merit Systems Protection Board Multistate Tax Commission National Aeronautics and Space Administration Secretary or administrative unit of the U.S. Navy National Credit Union Administration National Endowment for the Arts National Enforcement Commission National Highway Traffic Safety Administration National Labor Relations Board, or regional office or officer National Mediation Board National Railroad Adjustment Board Nuclear Regulatory Commission National Security Agency Office of Economic Opportunity Office of Management and Budget Office of Price Administration, or Price Administrator Office of Personnel Management Occupational Safety and Health Administration Occupational Safety and Health Review Commission Office of Workers' Compensation Programs Patent Office, or Commissioner of, or Board of Appeals of Pay Board (established under the Economic Stabilization Act of 1970) Pension Benefit Guaranty Corporation U.S. Public Health Service Postal Rate Commission Provider Reimbursement Review Board Renegotiation Board Railroad Adjustment Board Railroad Retirement Board Subversive Activities Control Board Small Business Administration Securities and Exchange Commission Social Security Administration or Commissioner Selective Service System Department or Secretary of the Treasury Tennessee Valley Authority United States Forest Service United States Parole Commission Postal Service and Post Office, or Postmaster General, or Postmaster United States Sentencing Commission Veterans' Administration War Production Board Wage Stabilization Board General Land Office of Commissioners Transportation Security Administration Surface Transportation Board U.S. Shipping Board Emergency Fleet Corp. Reconstruction Finance Corp. Department or Secretary of Homeland Security Unidentifiable International Entity