What follows is an opinion from the Supreme Court of the United States. Your task is to identify the federal agency involved in the administrative action that occurred prior to the onset of litigation. If the administrative action occurred in a state agency, respond "State Agency". Do not code the name of the state. The administrative activity may involve an administrative official as well as that of an agency. If two federal agencies are mentioned, consider the one whose action more directly bears on the dispute;otherwise the agency that acted more recently. If a state and federal agency are mentioned, consider the federal agency. Pay particular attention to the material which appears in the summary of the case preceding the Court's opinion and, if necessary, those portions of the prevailing opinion headed by a I or II. Action by an agency official is considered to be administrative action except when such an official acts to enforce criminal law. If an agency or agency official "denies" a "request" that action be taken, such denials are considered agency action. Exclude: a "challenge" to an unapplied agency rule, regulation, etc.; a request for an injunction or a declaratory judgment against agency action which, though anticipated, has not yet occurred; a mere request for an agency to take action when there is no evidence that the agency did so; agency or official action to enforce criminal law; the hiring and firing of political appointees or the procedures whereby public officials are appointed to office; attorney general preclearance actions pertaining to voting; filing fees or nominating petitions required for access to the ballot; actions of courts martial; land condemnation suits and quiet title actions instituted in a court; and federally funded private nonprofit organizations.

Opinion:
AIR POLLUTION VARIANCE BOARD OF COLORADO v. WESTERN ALFALFA CORP.
No. 73-690.
Argued April 25, 1974
Decided May 20, 1974
Douglas, J., delivered the opinion for a:unanimous Court.
William Tucker, Assistant Attorney General of Colorado,, argued the cause for petitioner. With him- on the brief were John P. Moore, Attorney General, John E: Bush, Deputy Attoméy General, and John Brown, Special.. Assistant Attorney General.
Donald D, Cawelti argued the cause for respondent. With him on the brief was George D. Blackwood,'Jr.
Edmund W. Kitch argued the cause for the United .States as amicus curiae urging reversal. Qn the- brief were. Solicitor General Bork, Assistant Attorney General Johnson, Harriet S. Shapiro, and Edmund B. Clark
Briefs of a7ff,ici curiae urging reversal were filed by William J. Brown, Attorney General, and Richard P. Fahey and John Eufinger, Assistant Attorneys General, for the the State of Ohio; and by the Attorneys General and other officials for'34 States as follows: Evette J.- Younger, Attorney General of California, Robert H. O'Brien, Assistant Attorney General, and Nicholas C. Yost, C. Foster Knight, and Daniel J. Taaffe, Deputy Attorneys General; Gary K. Nelson, Attorney General of Arizona; Jim Guy Tucker, Attorney General of Arkansas; Robert K. Killian, Attorney General of Connecticut; Arthur K. Bolton, Attorney General of Georgia; George Pai, Attorney- General of Hawaii; W. Anthony Park, Attorney General of Idaho; William' J. Scott, Attorney General of Illinois; Richard C. Turner, Attorney General of Iowa, and Clifford Peterson, Assistant . Attoijiey General; Vem Miller, Attorney General'of Kansas; Ed W. Hancock, Attorney General of Kentucky; William J. Guste, Jr., ■Attorney General of Louisiana; Jon A. Lund, Attorney General of Maine; Francis B. Burch, Attorney General of Maryland, and Martin A. Ferris III, Special-Assistant Attorney General; Robert H. Quinn, Attorney General of Massachusetts.'; Frank J. Kelley, Attorney General of Michigan; Warren R. Spannaus, Attorney General of Minnesota;- Clarence A. H. Meyer, Attorney General of Nebraska; Robert List, Attorney General of Nevada; Warren B. Rudman, Attorney General of New Hampshire, and Donald W. Stever, Assistant Attorney General; William F. Hyland, Attorney General of New Jersey; David L. Norvell, Attorney General of New Mexico; Louis J. Lefkowitz, Attorney General of New York;- Robert Morgan, Attorney General of North Carolina; AUen I.-Olson, Attorney General of North Dakota; Larry Derryberry, Attorney General of Oklahoma.; Lee Johnson,. Attorney Genefal of Oregon; Richard J. Israel, .Attorney General of Rhode Island; Daniel R. McLeod, Attorney General of South Carolina; Ker'mit A. Sande, Attorney. General of South Dakota, David M. .Pack, Attorney General of Tennessee; John L. Hill,. Attorney General.of Texas; Chauncey H. Browning, Jr., Attorney General of West Virginia; Robert W. Warren, Attorney General of Wisconsin, and Th&ódove L. Priebe-, Assistant Attorney General. ‘
Mr. Justice Douglas
delivered the opinion of the Court.
An inspector of a division of the. Colorado Department of Health entered the outdoor premises of respondent without its knowledge or consent. It was daylight and the inspector entered the yard to make a Ringelmann test of plumes of smoke being emitted from' respondent’s chimneys. Since that time Colorado has. adopted a requirement for a seareh warrant for. violations of air quality standards. At the time of the instant inspection the state law required nó warrant and none was sought. Indeed, the. inspector entered no part of respondent’s plant to make the inspection.
A federal Act under the administration of the 'Environmental Protection Agency (EPA) sets certain air quality . standards, 81 Stat. 485, 42 U. S. C. § 1857 et seg. The States have the primary responsibility to assure the maintenance of air. quality standards, 42 U. S. C. § 1857c-2 (a). Yet if the EPA has approved'or promulgated “an applicable implementation” plan, a State may not adopt Or enforce a “less stringent” one, 42 U. S. C. §4857d-1. - There is no conflict between a federal standard and state. action, the sole question presented being whether Colorado has violated federal constitutional procedures in making the inspection in the manner described..
Respondent requested a hearing before Colorado’s Air Pollution Variance Board. The Board held a hearing and found that respondent’s, emissions were in violation of the state Act. While the test challenged here was made on June 4, 1969, the Board after noting that Colorado’s Health Department had been in conference with respondent “in regard to its air pollution violations since September, 1967,” after approving the readings made by the field inspector on the day in question, and after holding that tests submitted in rebuttal by respondent were not acceptable, denied a variance and entered a ceasé-and-desist order. Respondent sought review in the District Court for Weld County which set aside the Board’s decision. The Colorado Court of Appeals affirmed, 610 P. 2d 907; and the Supreme Court denied certiorari.
The petition for certiorari which we granted, 414 U. S. 1166, raised three questions, presenting in differing postures questions under the Fourth Amendment, made applicable to the . States by the Fourteenth. Mapp v. Ohio, 367 U. S. 643.
The main, thrust of the opinion of the Court of Appeals is directed at the Fourth Amendment problem. It held that, under Camara v. Municipal Court, 387 U. S. 523, and See v. City of Seattle, 387 U. S. 541, the act of conducting the tests on the premises of respondent without either a warrant or .the cóñsent’of anyone from respondent constituted an unreasonable search within the meaning of the Fourth Amendment. We adhere to Camara and See btit we think they are not applicable here. The field inspector' did not enter the plant or offices.- - He was not inspecting stacks, boilers; scrubbers, flues, grates, or furnaces; nor was his inspection related to respondent’s files or papers. He had sighted what anyone in the city who was near the plant could see in the sky — plumes of smoke. The Court in Hester v. United States, 265 U. S. 57, 59, speaking through Mr. Justice Holmes, refused to extend the Fourth Amendment to sights seen in “the . open fields.” The field inspector was on respondent’s property but we are not advised that he was on premises from which the public was excluded. Under the Noise Control Act of 1972, 86 Stat. 1234, 42 U. S. C. § 4901 et.seq. (1970 ed., Supp. II), an inspector may enter a railroad right-of-way to determine whether noise standards are being violated. The .invasion of privacy in either that case or the present one, if it can be said to exist, is abstract and theoretical. The EPA regm lation for conducting an opacity test requires the inspector to stand at a distance equivalent to approximately two stack heights away but not more than & quarter of a mile from the base of the stack with the sun to his back from a vantage point perpendicular to the plume; and he must take at least 25 readings, recording the data at 15-to 30-second intervals. Depending upon the layout of the-plant, the inspector may operate within or without the premises but in either case he is well within the “open fields” exception to-the Fourth Amendment'approved.in Hester.
The Court of Appeals went on to say that since respondent was not aware that the inspector had been on the premises until the cease-and-desist notice, the hearing it received “lacked the fundamental elements of due process of law-, since.the secret nature of the investigation foreclosed Western from putting on any rebuttal .evidence.”
Whether the Court referred to Colorado “due process” or ■ Fourteenth Amendmept “due process” is not clear. If it is the former, the question is a matter of state law beyond our purview. Since we are unsure of the grounds of that ruling we intimate no opinion on that issue. But on our remand we leave open that.and any other, questions that may be lurking' in the case.
Reversed and remanded.
This test is prescribed by Colo. Rev. Stat. Ann. § 66-29-5 (Supp. 1967). It requires a'trained inspector to stand _iií a position where he' has an unobstructed view of the smoke plume, observe the smoke, and .rate it according to the opacity scale of the Ringelmann chart..- The person using the- chart matches the color and density of the sinoke • plume with • the numbered example on the chart. The Ringelmann test is generally sanctioned for use in measuring air pollution. See cases collected in Portland v. Fry Roofing Co., 3 Ore. App. 352, 355-358, 472 P. 2d 826, 827-829.
Colo. Rev. Stat. Ann. § 66-29-8 (2) (d) (Supp. 1969).
The Air Pollution Variance Board, after the Division of Administration; Colorado Department of Health, had issued a cease- .and-desist order; received a request from respondent for a hearing which was granted and held September 11,1969.
EPA studies indicate that tests of stacks are expensive and may . require 300 man-hours of skilled work. 39 Fed. Reg. 9309. And see Schulze; The Economics of Environmental Quality Measurement, 23 J. Air Poll Control Assn. 671. (1973); 40 CFR § 60.85, Method 9.
510 P. 2d, at 909.
In the District Court’s opinion it is said that one challenge to the hearing before the Variance Board "was “whether or not due • process of law ánd equal protection of -the law contrary to the 14th Amendment of the Constitution of the United States and Section 25, Article 2 of the Constitution of the State of Colorado was denied” by the Board. App. 136.
See California v. Krivda, 409 U. S. 33; Department of Mental Hygiene v. Kirchner, 380 U. S. 194; Minnesota v. National Tea Co., 309 U. S. 551,

Question: What is the agency involved in the administrative action?

Choices:
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
Bureau of Prisons
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 or Collector 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
Administrative agency established under an interstate compact (except for the MTC)
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 or personnel 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 or Board of Veterans' Appeals
War Production Board
Wage Stabilization Board
State Agency
Unidentifiable
Office of Thrift Supervision
Department of Homeland Security
Board of General Appraisers
Board of Tax Appeals
General Land Office or Commissioners
NO Admin Action
Processing Tax Board of Review

Answer: 116