Full opinion text
BOWNES, Circuit Judge. The Commonwealth of Puerto Rico appeals from the district court’s denial of its request for a comprehensive injunction against the United States Navy’s military training operations on the Island of Vie-ques, a municipality of the Commonwealth. Armed with a battery of federal and state laws, Puerto Rico alleged that the Navy’s activities in and around Vieques cause irreparable injury to the island’s ecology and its inhabitants. More specifically, Puerto Rico claimed that the Navy’s operations pollute the island’s air and its coastal waters, threaten the habitats of endangered species and many of the island’s irreplaceable historical sites, and diminish the productivity of the island’s fishing and agricultural resources. The Commonwealth also claimed that the Navy transferred certain training activities from the island of Culebra to Vie-ques, contrary to congressional and executive directives. After an extensive trial, the district court ordered the Navy to obtain a NPDES permit, prepare an environmental impact statement and obtain a determination on the eligibility of certain historical and prehistorical sites on the island for inclusion in the National Register of Historic Places. The court otherwise ruled in the Navy’s favor and refused to enjoin the training operations. Barcelo v. Brown, 478 F.Supp. 646 (D.P.R.1979). Before turning to the issues raised by Puerto Rico on appeal, we briefly sketch some basic characteristics of the island and the Navy’s activities. Vieques The island of Vieques lies six miles off the southeastern coast of Puerto Rico and approximately nine miles directly south of the island of Culebra. Situated on an east-west axis, Vieques is nearly twenty miles long with an average width of four miles. Of a total area of approximately 33,000 acres, the Navy owns 25,231.72 acres, or slightly more than 76% of the island. Certain features of the island’s ecology deserve particular mention. Fringe and offshore coral reefs are found in the coastal waters of Vieques, primarily off the northern, eastern and southern shores. Seagrass flourishes along the ocean floor adjacent to the coasts; the largest concentration runs from Punta Caballo on the north coast eastward around Punta Arenas to the southwest coast. There are also several large mangrove stands located along the shores; in the west near Punta Arenas and in the south around Puerto Mosquito, Puerto Ferro and Ensenada Honda. Three of the seven bioluminescent bays known to exist in the world are located along the southern coast — Puerto Mosquito, Puerto Ferro, and Bahia Tapón. Of the animal species living on Vieques, six are designated by the U. S. Fish and Wildlife Service as either “endangered” or “threatened.” 50 C.F.R. § 17.11. The “endangered” are the manatees, the brown pelicans, the leatherback turtles and the hawksbill turtles. Considered “threatened” are the green turtles and the loggerhead turtles. At least some of the nesting sites favored by the pelicans and the turtles are located within the areas where the Navy conducts its training operations. The human history of the island dates back at least to the ninth century A.D. At that time, Vieques served as a transit stop in the migration of Arawak Indians from the Orinoco Basin in South America (Venezuela) to Puerto Rico and Hispaniola (Haiti and the Dominican Republic). At the time of Columbus’ “discovery” of Vieques in 1493, the island was used by the Carib Indians as a temporary base from which they carried out raids against the people of Puerto Rico. Spain’s movement into the Caribbean during the sixteenth century resulted in the first permanent habitation of Vie-ques by Indians who sought to escape the Spanish occupation of Puerto Rico and St. Croix. Although Spain apparently never attempted to colonize Vieques, it periodically sent military expeditions to the island throughout the seventeenth and eighteenth centuries to maintain its hegemony over the island. The early years of the nineteenth century mark the beginning of Vieques’ modern history. In 1816 colonists from St. Croix and St. Thomas established the first livestock ranches, thus beginning what is today the island’s primary agricultural activity. Soon thereafter, one of the colonists organized the construction of a fort at Isabel Segunda. In addition to ranching, the economy of Vieques at this time involved timber harvesting for export to the Virgin Islands, subsistence farming and fishing. By the second half of the century, sugar cane had become the leading cash crop. After the Spanish American War of 1898, Vieques, together with the rest of Puerto Rico, became a Territory of the United States. The island’s economy continued to be dominated through the early 1940’s by sugar cane cultivation, ranching, and fishing. Since the mid 1940’s, however, the sugar cane industry has declined to a point where it is of no current importance to the island. Thus, the islanders now derive their livelihood from the same sources relied upon by their ancestors more than one hundred fifty years ago — fishing, subsistence farming and ranching. During the early 1940’s the Navy acquired title to most of its present holdings on Vieques. As a result of these acquisitions, civilians now occupy an area of about 7,000 acres, bounded on both the east and the west by Navy property. The present population distribution reflects the island’s economy. Of a total population of approximately 8,000, close to 5,000 people live in a rural environment outside the two coastal towns. Located on the northern coast' of the civilian sector is the capital, Isabel Segunda, which has between 2,400 and 2,500 inhabitants. Esperanza, the island’s other town, located on the southern coast, has a population of approximately 600. Navy Operations on Vieques The Naval Ammunition Facility (NAF) encompasses the entire area of Vieques west of the civilian zone. The Navy uses the facility for deep storage of conventional ammunition. Ships delivering the ordnance dock at Mosquito Pier, located on the northern coast of the NAF. From there, it is transported by truck to bunkers distributed throughout the NAF. Most of the ammunition is destined for off-island use by the Navy, the Marines and the Puerto Rican National Guard. Occasionally, ammunition is transferred overland from the NAF to the ground maneuver area located east of the civilian zone. The Navy’s installations on the eastern half of Vieques are part of a large military complex known as the Atlantic Fleet Weapons Training Facility, headquartered at Roosevelt Roads Naval Station in Ceiba, Puerto Rico. The facility consists of four firing ranges of which only two are related to Vieques. The outer range, a large area of ocean, at its closest points to Vieques lies thirty-five miles to the north and twenty miles to the south. Within this range, the Navy conducts exercises in ship to ship weapons fire, ship to air missile fire and air to air weapons fire. The underwater range, located off the western shore of St. Croix, involves training in three dimensional tracking of surface and underwater objects. The electronic warfare range is a network of “threat platform” simulators located in Puerto Rico and nearby islands. These are used to train shipboard and airborne electronic warfare teams and provide tactical electronic order of battle support for operations conducted on the other ranges. One simulator is positioned at the western end of Vieques atop Monte Pirata. Until recently, the inner range consisted of air to ground bomb and missile targets and naval gunfire support targets on Culebra, and air to ground, artillery and naval gunfire support targets on Vieques. In 1975, however, the Navy ceased its Culebra operations. Thus, the Vieques installations now comprise the entire inner range. The inner range is divided into four distinct areas. The ground maneuver area (GMA) extends from the civilian sector eastward for approximately seven miles to a cattle fence which runs the width of the island. Located at the southwestern corner of the GMA is Camp Garcia, a Marine Corps camp which, although able to accommodate several thousand troops, is occupied by one marine. The principal use of the GMA is for Marine amphibious landings. These are conducted throughout the year, primarily on the southern beaches between Punta Conejo and Punta Negra. A typical landing will require the use of large attack transports from which are launched the landing craft and amphibious tracked vehicles. These smaller craft carry troops, tanks and other equipment to the beaches. Once landed, the troops perform maneuvers throughout the GMA, which at times include artillery fire. Upon completion of the land exercise the troops embark from the beaches and return to the attack transports. An amphibious landing usually is accompanied by low-level support flights by fixed wing jet aircraft and helicopter gunships. An amphibious exercise may involve anywhere from two to twenty thousand troops; it may be independent of other inner range operations, or it may be part of a single large-scale maneuver in concert with the Navy’s sea and air forces. The surface impact area (SIA) begins about one mile east of the cattle fence and extends approximately two and one-half miles east to a “firebreak” designated as the western friendly front line. Artillery training, strafing and air to ground bombing, the latter two using inert ammunition only, occur within this area. The artillery is positioned near the western border of the SIA — about six miles from the nearest point in the civilian zone — loaded with live ammunition and fired at targets located in the eastern part of the SIA. Air to ground bombing is directed at two bullseye targets. Target # 2 is situated about one-half mile east of the SIA’s western boundary; target # 1 is on a point along the northern half of the western friendly front line. The strafing targets are located at the southern most point of the firebreak. The Air Impact Area (AIA), also known as the Close Air Support Zone (CAS), runs from the western friendly front line eastward for about two miles to the eastern friendly front line. This area, in which live ammunition is used, contains as targets mockups of two surface to air missile sites, an airstrip, a fuel farm and an ammunition dump. There are also two remote controlled moving targets inland and six naval gunfire support targets along the southern coast of the AIA. No targets exist in the area between the eastern friendly front line and Punta Este, the easternmost point of Vieques. An infrequently used water target lies about one mile east of this point. Air and sea operations in the inner range occur about 200 days out of a year, usually between 7:30 a. m. and 10:00 p. m. Operations are directed by observers positioned in an observation post on Cerro Matías, located in the southeastern part of the SIA. Aircraft taking off from the Roosevelt Roads airfield or a carrier located north of Vieques first fly north of Vieques and then circle around the eastern coast to approach the range from the south. Aircraft taking off from carriers located south of Vieques use a straight approach from that direction. Any aircraft carrying ammunition, whether live or inert, is prohibited from flying over the civilian area. As best as can be estimated, an aircraft training in the range would ordinarily come no closer than within five and three-quarters miles of the civilian zone. Ship to shore gunnery directed at the naval gunfire support targets in the AIA is also restricted to a southern approach. When firing, the ships are usually positioned between three and eleven miles off the southern shore of the AIA. All ship to shore firing occurs within a designated danger zone, which permits the Navy to prohibit all civilian navigation while the area is in use. The Issues on Appeal Puerto Rico challenges the district court’s rulings on the following issues: 1. Did the Navy “transfer” training activities from Culebra to Vieques in violation of certain Military Construction Authorization Acts? 2. Does the dropping of ordnance into the coastal waters of Vieques violate the Puerto Rico Water Quality Standards, contrary to the requirements of § 313 of the Federal Water Pollution Control Act Amendments of 1972, 33 U.S.C. § 1323(a)? 3. Did Congress intend to permit a private cause of action to enforce § 13 and § 15 of the Rivers and Harbors Act of 1899, 33 U.S.C. §§ 407, 409? 4. Does the danger zone regulation promulgated by the Corps of Engineers, 33 C.F.R. § 204.234, unreasonably restrict the food fishing industry of Vieques contrary to 33 U.S.C. § 3? 5. Do the Navy’s training activities generate such noise as to create a public nuisance in violation of Puerto Rico’s criminal nuisance statute, P.R.Laws Ann. tit. 33, § 1365,"and the requirements of § 4 of the Noise Control Act, 42 U.S.C. § 4903(a)? 6. Do the Navy’s activities on Vieques violate the Endangered Species Act of 1973, 16 U.S.C. §§ 1531-1543? 7. Does the Navy’s survey of historical sites on Vieques satisfy the requirements of § 106 of the National Historic Preservation Act, 16 U.S.C. § 470f, Executive Order 11593 and 36 C.F.R. § 800.4? 8. Should the Navy be enjoined from conducting training operations on Vieques? After oral argument, we requested that the parties submit supplemental briefs on the question of whether any of the plaintiffs have a right of action to challenge the alleged violations of certain military authorization acts and executive branch directives related to training activities on Culebra and Vieques. With the benefit of briefs from both parties, we first address that question. Right to Challenge the Alleged Transfer of Military Training Activities Puerto Rico alleged that the Navy “clandestinely” has transferred training operations from Culebra to Vieques, contrary to the “clear command” of the Military Construction Authorization Acts of 1971, 1972 and 1974. The district court rejected this contention, ruling that the statutes do not establish an enforceable mandate, and expressed serious doubt that a transfer of activities actually had occurred. On appeal, Puerto Rico argues that the trial court’s narrow view of the acts ignores Congress’ “carefully crafted” statutory “procedure” intended to protect the interests of the Commonwealth; Puerto Rico also challenges the court’s finding that a transfer did not in fact occur. Our initial task is to ascertain whether Congress intended to permit the Commonwealth, or any other party, to seek judicial enforcement of the three authorization acts. As with any question of statutory interpretation, we begin with an examination of the language of the statutes and the related executive branch directives. Transamerica Mortgage Advisors, Inc. v. Lewis, 444 U.S. 11, 16, 100 S.Ct. 242, 245, 62 L.Ed.2d 146 (1979); Touche Ross & Co. v. Redington, 442 U.S. 560, 568, 99 S.Ct. 2479, 2485, 61 L.Ed.2d 82 (1979). In October 1970 Congress adopted the Military Construction Authorization Act of 1971, Pub.L.No.91-511, 84 Stat. 1204. Section 611(a) of the Act directed the Secretary of Defense “to prepare a report of the weapons training now being conducted in the Culebra complex .... ” The Secretary was ordered to evaluate “all possible alternatives, geographical and technological,” and make “recommendations for ... moving all or part of such activities to a new site or sites,” giving particular consideration to six factors: (1) the safety and well-being of the people who live on Culebra; (2) the natural and physical environment of Culebra and adjoining cays and their recreational value; (3) the development of a sound, stable economy in Culebra; (4) the unique political relationship of Culebra and Puerto Rico to the United States; (5) the operational readiness and proficiency of the Atlantic Fleet; and (6) national security. Section 611(b) provided that the report was to be prepared in consultation “with the people of Culebra, the Government of Puerto Rico, and all appropriate federal agencies.” Finally, the Navy was directed to “avoid any increase or expansion of the present weapons range activities in the Culebra complex and, wherever possible, without degrading the activities, to institute procedures which will minimize interference with the normal activities and the solitude of the people of Culebra.” On April 1, 1971, Secretary of Defense Laird transmitted to Congress and the President the mandated report. In a press release issued the same day, the Secretary announced that he had ordered the Navy “to institute immediately a number of actions which will enhance the safety and well being of the residents of Culebra and reduce the irritants to them resulting from Navy training.” The Secretary also expressed his intention to reappraise the situation by the end of 1972 and make a final decision about where to relocate the Culebra operations. With the enactment in 1971 of § 207 of the Military Construction Authorization Act of 1972, Pub.L.No.92-145, 85 Stat. 394, Congress directed the Secretary of Defense to prepare a new study of “the most advantageous alternative [to the Culebra training complex] on the basis of investigations which consider cost, national security, the operational readiness and proficiency of the Atlantic Fleet, the impact on the environment, and other relevant factors.” On December 27, 1972, Secretary Laird submitted his report and recommendations to the President and Congress. In an accompanying letter he identified Vieques as the best of the available alternative sites but concluded “that the Culebra complex offers such advantages over all other alternatives studied that none of these other alternatives can be considered reasonable.” Relocation to Vieques “would significantly reduce the capability of the Inner Range and would transfer the training activity from an island with 700 inhabitants to one with 7,000 inhabitants,” an “[im]prudent course of action.” Thus, he recommended “that the Navy retain its training targets in the Culebra complex,” yet “remain abreast of developments that would modify ... the Navy’s need” for the Culebra range. In the following spring of 1973, Secretary Laird’s successor, Elliot Richardson, informed the Secretary of the Navy that it was in the Defense Department’s long-range interest to transfer the Culebra training activities to the islands of Desecheo and Monito by July 1,1975. This relocation was to occur, however, only after Congress had appropriated the necessary funds and the Navy had achieved a “satisfactory overall arrangement with the government of Puerto Rico for carrying out the proposed move and for insuring the long-term continuation of the Atlantic Fleet Weapons Range and the Fleet Marine Force training area.” Congress responded to this change in the Defense Department’s position with the enactment in 1973 of the Military Construction Authorization Act of 1974. Pub.L.No. 93-166, 87 Stat. 668. Section 204(a) of the Act authorized the appropriation of $12,-000,000 to facilitate the relocation of the Culebra training operations. But § 204(b) “expressly conditioned [the relocation] upon the conclusion of a satisfactory agreement to be negotiated by the Secretary of the Navy ... with the Commonwealth of Puerto Rico and reported to the Committees on Armed Services of the Senate and the House of Representatives prior to execution of such agreement.” Congress directed that “the agreement shall provide, among other things, that the Commonwealth of Puerto Rico shall insure that (1) Commonwealth lands suitable for carrying out operations of the type referred to in subsection (a) will be made available for the long-term continued use of the Atlantic Fleet Weapons Range and Fleet Marine Forces training areas by the Navy, including, but not limited to, present areas and facilities on the island of Vieques .... ” Despite the absence of an agreement between the Navy and Puerto Rico, on June 22, 1974, Secretary of State Kissinger, acting as National Security Adviser, informed the Secretary of Defense of the president’s decision to terminate the training activities on Culebra by July 1,1975, and those on the Culebra Cays by December 31, 1975. Kissinger directed the Secretary of Defense “to consider and select alternative sites for the weapons range activities” and stated that “[t]he selection of the new site, if it is in Puerto Rico, will be contingent on its being acceptable to the Commonwealth .... ” The Navy has ceased its operations on Culebra and negotiations continue over the selection of a new site. When Congress has not expressly provided for private enforcement of a statute, there is little likelihood that the legislative history will disclose whether Congress nonetheless intended that result. Cannon v. University of Chicago, 441 U.S. 677, 694, 99 S.Ct. 1946, 1956, 60 L.Ed.2d 560 (1979). Thus, the statutory language becomes the best evidence of Congress’ intent. As the Supreme Court recently recognized, in each of its earlier cases that did imply a private cause of action the statute in question either conferred a federal right on private parties or proscribed certain conduct. Touche Ross & Co. v. Redington, 442 U.S. at 569, 99 S.Ct. at 2485. Implicit in this observation is that the absence of statutory language that either prohibits some action or confers rights weighs heavily against implication of a private cause of action. Neither the Military Construction Authorization Act of 1971 nor the 1972 Act creates rights or proscribes conduct of any relevance to this case. The 1971 Act’s partial restriction of the Navy’s activities in Culebra was unrelated to Navy operations on the other islands of the Commonwealth. In contrast, the 1974 Act made the relocation of the Navy’s Culebra operations contingent on the execution of an agreement between the Navy and Puerto Rico. But even if we characterize this as a limited prohibition, it appears from the language of the pertinent provision and the accompanying committee report that the condition was imposed to benefit the Navy rather than Puerto Rico. Section 204(b) required that the agreement contain assurances from the Commonwealth “that Commonwealth lands suitable for carrying out operations ... will be made available for the long term continued use of the ... Navy, including, but not limited to, present areas and facilities on the island of Vieques .... ” Not only does this language impose an obligation on the Commonwealth rather than the Navy, but it forecloses negotiation over the training areas and facilities on Vieques. In the same vein, the joint conference report that accompanied the final draft of the Act states: The restrictive language in Section 204 is a result of discussion with the Governor and others and the conferees believe it provides sufficient protection to the Navy upon relocation of ship-to-shore gunfire operations from Culebra to the other Islands mentioned. H.R.Rep.No.634, 93d Cong., 1st Sess. 35 (1973). If Congress had intended to create a private right of action, it would have provided first for a right or duty upon which private enforcement could be based. But the authorization acts leave Puerto Rico without a place to hang its hat; the statutes grant no right to the Commonwealth, nor do they impose an obligation on the Navy for the benefit of the Commonwealth. Puerto Rico argues that the authorization acts reflect Congress’ intention to obligate the Navy to confer with other parties, particularly the Commonwealth, prior to any transfer of the Culebra operations. As part of that argument, Puerto Rico maintains that Congress anticipated that the agreement mandated by the 1974 Act would provide for “other things” beyond the Commonwealth’s assurances of an adequate alternative site. The Commonwealth contends that this phrase undoubtedly was intended to encompass provisions for the protection of its environment and the welfare of its citizens; Congress impliedly sought to prevent a recurrence of the ecological and political problems created by the Navy’s use of Culebra. Puerto Rico concludes that as the party most to be benefitted from this inferred congressional prohibition of unilateral Navy action, it must be granted a cause of action to vindicate Congress’ intent. Other than the phrase “among other things,” however, Puerto Rico is unable to direct us to one provision in any of the three acts that establishes the mandate it seeks to enforce. Instead, it relies primarily on the “necessary” inferences to be drawn from the statutes and the executive branch directives; Puerto Rico interprets the latter documents to corroborate its position. But the expansive inferences drawn by Puerto Rico, which we do not find to be free from doubt, must be contrasted with the limited nature of the legislation. The 1971 Act and the 1972 Act, as related to Vieques, directed the Secretary of Defense to prepare two feasibility reports; that is all. The 1974 Act did mandate execution of an agreement prior to relocation from Culebra. So far as the statute provides, however, we know only that Congress intended by this condition to protect the Navy’s training capacity. Congress may have had a clear collective understanding of what “other things” were at issue, and the preferred resolution, but it chose not to reflect this in its 1974 legislation. Instead, it left to the parties the task of hashing out an agreement, subject to congressional, not judicial, review. The absence of any enforcement scheme in the authorization acts reinforces our conclusion that Congress intended that the controversy surrounding the Navy’s training activities in Puerto Rico be resolved in the political sphere. Implication of a private cause of action would be contrary to the apparent intent of Congress, and, given the lack of a judicially enforceable mandate, a futile gesture. Puerto Rico relies on the various executive branch directives principally to corroborate its interpretation of the authorization acts. As a second line of argument, however, it maintains that the directives have independent significance as sources of a private right of action. Unlike the situation presented by the three statutes, at least one of the directives contains a provision which ordered the Navy to obtain the Commonwealth’s agreement prior to a relocation of the Culebra operations. In 1974 National Security Adviser Kissinger, on behalf of the President, directed the Secretary of Defense to end the Culebra operations and select a new site contingent on its being acceptable to the Commonwealth. Puerto Rico contends that this order imposed a legal obligation on the Navy that is enforceable by the Commonwealth. We conclude, however, that the President’s order does not have the force and effect of law and thus is not enforceable by an implied private cause of action. The Commonwealth attempts to cloak the 1974 presidential order with statutory authority, characterizing it as in furtherance of the 1974 Act. But in fact the order essentially ignored what we perceive to be the intent of Congress as evidenced in the Act. Rather than require the Commonwealth to insure alternative sites prior to a relocation of the Culebra operations, as Congress mandated, the President ordered termination of those operations without any prior assurances from Puerto Rico. Moreover, the order granted the Commonwealth a veto over the Navy’s choice of an alternative site; nothing in the Act suggests that Congress intended such a role for the Commonwealth. When the President issued this order, he necessarily relied not on any statutory authority, but on his constitutional authority as the chief executive and the commander in chief of the armed forces. As such, the President has the power to direct the activities of the military but he is without the authority to legislate. See Youngstown Sheet & Tube Co. v. Sawyer, 343 U.S. 579, 587-88, 72 S.Ct. 863, 867, 96 L.Ed. 1153 (1952). Without some basis in an act of Congress, the directive cannot constitutionally be invested with the status of law, see Independent Meat Packers Ass’n v. Butz, 526 F.2d 228, 234-36 (8th Cir. 1975), thus obviating a decision on the question of an implied cause of action. The Commonwealth’s reliance on section 10 of the Administrative Procedure Act as an alternative source for a cause of action founders upon the limitations inherent in the Act. Section 10(a) of the APA provides that “[a] person suffering legal wrong because of agency action, or adversely affected or aggrieved by agency action within the meaning of a relevant statute, is entitled to judicial review thereof.” 5 U.S.C. § 702. But assuming that the Navy did “transfer” the Culebra activities to Vieques, that action is not “agency action.” Section 2 of the APA defines agency action to include “the whole or a part of an agency rule, order, license, sanction, relief or the equivalent or denial thereof, or failure to act .... ” Id. § 551(13). Each of the types of action included within this definition is separately defined in § 2. See id. § 551(4), (6), (8), (10), (11). All but one of these specific definitions refer to one of two forms of regulatory activity — agency rulemaking or agency adjudication. “Sanction” is defined to include, in addition to regulatory activity, “any agency ... destruction, taking, seizure or withholding of property.” Id. § 551(10). The Navy’s transfer of military training activities did not remotely involve rulemaking or adjudication, nor, at least in this case, did it result in the “destruction, taking, seizure or withholding of property.” We recognize that Congress intended the APA to span a “broad spectrum of administrative actions.” Abbott Laboratories v. Gardner, 387 U.S. 136, 140, 87 S.Ct. 1507, 1511, 18 L.Ed.2d 681 (1967). Nonetheless, the language of § 2 evidences that Congress intended to reach only actions that are administrative, and we conclude that the challenged activities of the Navy do not fall within that spectrum. But see Standard Oil Co. of Ca. v. F.T.C., 596 F.2d 1381, 1384-85 (9th Cir. 1979). Even if we were to accept that the “transfer” constituted agency action, we would characterize it as action “committed to agency discretion by law,” 5 U.S.C. § 701(a)(2), and thus unreviewable. This exception to § 10’s broad entitlement to judicial review applies only “in those rare instances where ‘statutes are drawn in such broad terms that in a given case there is no law to apply.’ ” Citizens to Preserve Overton Park v. Volpe, 401 U.S. 402, 410, 91 S.Ct. 814, 820, 28 L.Ed.2d 136 (1971), quoting S.Rep.No. 752, 79th Cong., 1st Sess. 26 (1945). See Chrysler Corp. v. Brown, 441 U.S. 281, 317, 99 S.Ct. 1705, 1725, 60 L.Ed.2d 208 (1979). The question before us presents one of those rare instances. The Commonwealth has cited as the applicable constraint on the Navy’s training activities the Military Construction Authorization Acts of 1971, 1972 and 1974. But, as we have already explained in some detail, those statutes do not provide the judiciary with any “law to apply.” We affirm the district court’s ruling that with respect to the alleged transfer of military training activities from Culebra to Vie-ques, Puerto Rico has failed to state a claim upon which relief can be granted. Pollution of the Coastal Waters 1. Puerto Rico Water Quality Standards Section 313 of the Federal Water Pollution Control Act Amendments subjects every “department, agency, or instrumentality of the executive, legislative and judicial branches of the Federal Government” to “all Federal, State, interstate, and local requirements ... respecting the control and abatement of water pollution in the same manner and to the same extent as any nongovernmental entity.” 33 U.S.C. § 1323(a). Puerto Rico alleged that the Navy, by dropping ordinance into the waters of Vieques, has violated several water pollution control regulations promulgated pursuant to the Commonwealth’s Water Pollution Control and Public Policy Environmental Control Acts. The district court rejected this allegation, finding no violation of the water quality standards it deemed applicable to the Navy’s activity. 478 F.Supp. at 664-69. On appeal, Puerto Rico asserts that, contrary to the trial court’s opinion, there are three germane water quality standards that the Navy has violated. We consider each separately. Article 2.1.1 of the Puerto Rico Water Quality Standards provides: The waters of Puerto Rico shall not contain materials attributable to discharges that will settle to form objectionable deposits. Nor will they contain floating debris, scum, oil and other floating materials attributable to discharges in amounts sufficient to be unsightly or deleterious. Puerto Rico argues that the trial court erred in its interpretation of 2.1.1 by according determinative significance to the term “discharges,” contrary to the purposes of the regulations and statute. We cannot agree. Article 2.1.1 expressly and exclusively addresses materials “attributable to discharges,” which are defined as “[t]he outflow of wastewater from any ... source into receiving waters.” Article 1. Turning to the definition of wastewater, we are directed to the definition of municipal wastes, which is “[wjater carrying human and animal wastes from homes, buildings, industrial establishments and other places alone or in combination with industrial wastes.” Id. No fair reading of this language warrants the conclusion that Article 2.1.1 applies to the bombing and shelling of coastal waters. In contrast, the prohibitions annunciated in Article 2.1.3 are not limited in application to materials attributable to discharge. Article 2.1.3 directs that “[t]he waters of Puerto Rico shall not contain substances in concentrations or combinations which produce undesirable physiological responses in human, fish or other animal life, and plants.” More specifically, subsection (A) establishes with respect to the coastal waters the “maximum allowable concentrations” of iron and certain other inorganic substances. Puerto Rico contends that the district court ignored the general prohibition of “substances ... which produce undesirable physiological responses” and erred in its finding that the Navy’s activity did not result in a violation of the maximum allowable concentration of iron. The weakness in Puerto Rico’s first contention is that it reads into Article 2.1.3 an unjustifiable breadth in scope. Article 2.1.3 speaks not simply of “substances,” which, admittedly, could be construed to encompass solids such as spent ordinance as well as other refuse. Rather, the regulation addresses “concentrations” or “combinations” of substances. Those terms appear to refer in this context to the presence of chemicals and chemical processes rather than that of solids such as discarded ordnance. For example, the “maximum allowable concentrations” established by 2.1.3 are expressed in terms of milligrams per liter, hardly a measurement appropriate to shell casings or bomb remnants. And those limitations are devoted to the specification of allowable concentrations of minerals and pesticides, not those of solids. We conclude that the apparent thrust of this regulation is the control and abatement of chemical pollution. We therefore agree with the district court that the sole issue under Article 2.1.3 is whether the Navy’s used ammunition caused concentrations of iron in certain areas of the coastal waters to exceed the specified maximum allowable concentration. With respect to this question, we find nothing in the record to contradict the trial court’s finding. Although it appears fairly clear that the concentrations of iron in some areas near the target range do exceed the Article 2.1.3(A) standard, Puerto Rico failed to establish that ordnance dropped by the Navy caused these excessive concentrations of iron. Thus, the district court correctly found no violation of Article 2.1.3. Finally, we turn to the broadly phrased prohibition of Article 4 of the Water Quality Standards. Article 4.1.1 provides that “[n]o person shall cause or permit the pollution of the waters of Puerto Rico .... ” Pollution is defined in Article 1 as [altering the natural characteristics of a body of water so as to make it in any way harmful or noxious to human health, or to that of animals, or plants, or rendering it ill-smelling or impure or altering adversely its physical, chemical, microbiological or radioactive condition, in such a way as to interfere with enjoyment of life or property or violate the standards of purity established by this Regulation. Puerto Rico argues that the district court failed to apply Article 4.1.1 as a “generic” prohibition distinct from the specific standards set forth in Article 2. We conclude, however, that Article 4.1.1 does not constitute a “standard ’ as referred to in Puerto Rico’s Water Pollution Control Act. The statutory prohibition of pollution makes it “unlawful for any person ... to throw, discharge, pour or dump . .. into the waters ... any organic or inorganic matter capable of polluting” these waters “in such a manner as to place them out of the minimum standards of purity that the [Board on Environmental Quality] may establish .. .. ” P.R.Laws Ann. tit. 24, § 595. Similarly, the statute defines pollution as “making [the waters] in any way noxious ... all according to the permissible standards of purity ... established as provided herein.” P.R.Laws Ann. tit. 24, § 591(i). This language evidences the legislature’s judgment that the general prohibition of pollution is not enough; standards explicating what pollution is must be provided. The statute anticipates administrative specification of its broad proscription in the form of standards by which particular actions may be evaluated. But Article 4.1.1 merely rephrases the general statutory command; it offers no clarification of that language, nor, unlike Article 2, does it provide any additional guidance to those who must conform to the law. To accept 4.1.1 as a “standard” would render meaningless the statutory requirement that the regulations promulgated thereunder further define and clarify the general statutory proscription of pollution. Because Article 4.1.1 is not a standard as contemplated by the authorizing statute, we decline to give it effect separate from the actual standards of the Regulation. We affirm the district court’s conclusion that the Navy has not violated the applicable Puerto Rico Water Quality Standards or 33 U.S.C. § 1323(a). 2. The Rivers and Harbors Act of 1899 The second phase of Puerto Rico’s attempt to halt the Navy’s dropping of ordnance into the coastal waters of Vieques rests primarily on an alleged violation of Section 13 of the Rivers and Harbors Act of 1899, 33 U.S.C. § 407. As a complement to that claim, Puerto Rico alleged that the Navy’s sinking of the U.S.S. Killen in the Bahia Salinas del Sur violated Section 15 of the same act, 33 U.S.C. § 409. The district court ruled that neither § 13 nor § 15 give rise to a private cause of action for injunctive relief, 478 F.Supp. at 669-72. We affirm that decision with respect to § 13, but vacate the court’s ruling with respect to § 15. Section 13 makes it unlawful to throw, discharge or deposit “any refuse matter ... into any navigable water of the United States ...” without a permit from the Administrator of the Environmental Protection Agency. 33 U.S.C. §§ 407, 1342(a). The “comprehensive language” of this prohibition reflects a broad statutory purpose — the protection of navigation and the prevention of pollution. United States v. Standard Oil Co., 384 U.S. 224, 228-30, 86 S.Ct. 1427, 1429-1430, 16 L.Ed.2d 492 (1966). See United States v. Pennsylvania Industrial Chemical Corp., 411 U.S. 655, 93 S.Ct. 1804, 36 L.Ed.2d 567 (1973). Under § 17 of the Act, it is the duty of the Department of Justice to “conduct the legal proceedings necessary to enforce the provisions” of § 13.33 U.S.C. § 413. Although the Act expressly provides for criminal penalties only, id., courts have recognized the federal government’s implied authority to seek injunctive relief for a violation of § 13. United States v. Stoeco Homes, Inc., 498 F.2d 597 (3d Cir. 1974), cert. denied, 420 U.S. 927, 95 S.Ct. 1124, 43 L.Ed.2d 397 (1975). See Wyandotte Transp. Co. v. United States, 389 U.S. 191, 88 S.Ct. 379, 19 L.Ed.2d 407 (1967); Connecticut Action Now, Inc. v. Roberts Plating Co., 457 F.2d 81 (2d Cir. 1972). Puerto Rico argues that the broad purposes of § 13 also warrant the implication of a private cause of action for injunctive relief. We undertake an analysis of this claim mindful of the Supreme Court’s recent adherence “to a stricter standard for the implication of private causes of action ....” Touche Ross & Co. v. Redington, 442 U.S. 560, 578, 99 S.Ct. 2479, 2490, 61 L.Ed.2d 82 (1979). The touchstone of this inquiry is whether Congress intended that the statute be enforced by private parties. Transamerica Mortgage Advisers, Inc. v. Lewis, 444 U.S. 11, 15, 100 S.Ct. 242, 245, 62 L.Ed.2d 146 (1979); Touche Ross & Co. v. Redington, 442 U.S. at 568, 99 S.Ct. at 2485. That intent usually can best be ascertained by addressing four factors. See Cort v. Ash, 422 U.S. 66, 78, 95 S.Ct. 2080, 2088, 45 L.Ed.2d 26 (1975). First, it must be determined from the statutory language “whether the statute was enacted for the benefit of a special class of which the plaintiff is a member.” Cannon v. University of Chicago, 441 U.S. 677, 689, 99 S.Ct. 1946, 1953, 60 L.Ed.2d 560 (1979). The duties imposed by § 13 benefit the public at large; nothing in the statutory language identifies any special class as the principal intended beneficiary. Rather, if there is a principal beneficiary of § 13’s proscription, it is the “Government itself.” Wyandotte Transp. Co. v. United States, 389 U.S. at 201, 88 S.Ct. at 385-386. With a statute such as § 13, one which creates “duties on the part of persons for the benefit of the public at large,” the Supreme Court “has been especially reluctant to imply causes of actions.” Cannon v. University of Chicago, 441 U.S. at 691-92 n.13, 99 S.Ct. at 1954-1955 n.13. The second factor requires an investigation of the legislative history. As the Supreme Court has recognized, however, little is likely to be learned from the legislative history of a statute which is silent on the question of private enforcement. Id. at 694, 99 S.Ct. at 1956. The debates and reports preceding § 13’s enactment at most evidence that Congress had no intent with respect to this question. See Touche Ross & Co. v. Redington, 442 U.S. at 571, 99 S.Ct. at 2486. The third factor is whether it is “consistent with the underlying purposes of the legislative scheme to imply such a remedy ....” 441 U.S. at 688-89 n.9, 99 S.Ct. at 1953 n.9. Section 17 of the Act provides that “[t]he Department of Justice shall conduct the legal proceedings necessary to enforce” § 13.33 U.S.C. § 413. The only role expressly created for private persons in the enforcement scheme is as informants; section 17 provides for the payment of one-half of a levied fine “to the person or persons giving information which shall lead to conviction.” Id. § 411. In one respect, a private cause of action is clearly consistent with the legislative scheme. It would positively augment the government’s enforcement efforts, thus better effectuating the ultimate objectives of § 13. But notwithstanding the remedial advantages to be gained from such implication, the language of these provisions establishes that Congress vested in the federal government the primary responsibility for enforcement. To the extent that this decision involved factors other than the protection of navigation and the prevention of pollution, implication of a private cause of action could very well frustrate Congress’ intent. See Connecticut Action Now, Inc. v. Roberts Plating Co., 457 F.2d at 89. Finally, we must consider “whether implying a federal remedy is inappropriate because the subject matter involves an area basically of concern to the States.” Cannon v. University of Chicago, 441 U.S. at 709, 99 S.Ct. at 1964. The federal interest in navigation and the control of pollution cannot be doubted. Congress’ power under the Commerce clause gives that body virtually plenary authority over the navigable waters of the United States. See, e. g., Gilman v. Philadelphia, 70 U.S. (3 Wall.) 713, 18 L.Ed. 96 (1865); Gibbons v. Ogden, 22 U.S. (9 Wheat.) 1, 6 L.Ed. 23 (1824). Since the enactment of the Rivers and Harbors Act in 1899, Congress has expanded federal efforts to control the pollution of navigable waters with the adoption of the Federal Water Pollution Control Act, as amended, 33 U.S.C. §§ 1251-1376. The enactment in 1969 of the National Environmental Policy Act, 42 U.S.C. §§ 4321-4347, underscores the federal commitment to combat pollution. We perceive no federalism-comity problems militating against the implication of a private cause of action under § 13. Of the four factors we have analyzed to ascertain Congress’ intent, only the last clearly favors implication of a private cause of action. Although we recognize that private enforcement of § 13 might be conducive to the protection of navigation and the control of pollution, “[t]he ultimate question is one of congressional intent, not one of whether this Court thinks that it can improve upon the statutory scheme ....” Touche Ross & Co. v. Redington, 442 U.S. at 578, 99 S.Ct. at 2490. What evidence there is does not warrant a conclusion that Congress intended to create a private cause of action under § 13. Section 15 of the Rivers and Harbors Act makes it unlawful “to voluntarily, or carelessly sink, or permit or cause to be sunk, vessels or other craft in navigable channels .... ” 33 U.S.C. § 409. Puerto Rico maintains that the Navy’s intentional sinking of a target ship, the U.S.S. Killen, in the Bahia Salinas del Sur, violated this prohibition. We conclude that Puerto Rico is without standing to assert this claim. “The essence of the standing inquiry is whether” the plaintiff has alleged “a ‘distinct and palpable injury’ ... ‘fairly traceable’ ... to the challenged conduct.” Duke Power Co. v. Carolina Env. Study Group, 438 U.S. 59, 73, 98 S.Ct. 2620, 2630, 57 L.Ed. 595 (1978) (citations omitted). Puerto Rico failed to allege that the sinking of the U.S.S. Killen resulted in any form of harm to the island or its inhabitants. Nor does the relief requested — an injunction against the Navy’s training activities on Vieques— implicitly suggest the harm which Puerto Rico might have alleged. An injunction against current Navy activities hardly would remedy any injury to the environment or navigation caused by a sunken vessel. Removal of the ship would be the appropriate remedy for harm resulting from the ship’s presence, but Puerto Rico did not request that relief. The failure to allege a distinct and palpable injury renders Puerto Rico’s claim under § 15 nonjusticiable. See Simon v. Eastern Kentucky Welfare Rights Org., 426 U.S. 26, 39, 96 S.Ct. 1917, 1924, 48 L.Ed.2d 450 (1976); Linda R.S. v. Richard D., 410 U.S. 614, 617, 93 S. Ct. 1146, 1148, 35 L.Ed.2d 536 (1973). Thus, we vacate the district court’s decision with respect to this claim, and remand with instructions to dismiss for lack of jurisdiction. Restrictions on Fishing “In the interest of the national defense, and for the better protection of life and property,” section 1 of the Army Appropriation Act of 1918 authorizes the Secretary of the Army “to prescribe such regulations as he may deem best for the use and navigation of any portion or area of the navigable waters ... under the jurisdiction of the United States endangered or likely to be endangered by Artillery fire in target practice or otherwise .... ” 33 U.S.C. § 3. The sole express restraint imposed by the statute on the Secretary’s power provides “that the authority conferred shall be so exercised as not unreasonably to interfere with or restrict the food fishing industry .... ” Id. Pursuant to this authority, the Secretary has promulgated danger zone regulations individually tailored to the particular area of water in question. See 33 C.F.R. § 204. In 1974 the Secretary of the Army promulgated the following regulation: Carribean Sea and Vieques Sound in vicinity of Eastern Vieques, bombing and gunnery target area. (a) The Danger Zone. From Punta Conejo on the south coast of Vieques at latitude 18°06'30", longitude 65°22'33"; thence to latitude 18°03'00", longitude 65°21'00"; thence to latitude 18o03'00", longitude 65°15'30"; thence to latitude 18°11'30", longitude 65°14'30"; thence to latitude 18°12'00", longitude 65°20'00"; and thence to Cabellos Colorados on the north coast of Vieques at latitude 18°09'49", longitude 65°23'27", (b) Regulations. (1) It will be open to navigation at all times except when firing is being conducted. At such times no surface vessels, except those patrolling the area, shall enter or remain within the danger area. Prior to conducting each firing or dropping or ordnance the danger area will be patrolled to insure that no watercraft are within the danger area. Any watercraft in the vicinity will be warned that practice firing is about to take place and advised to vacate the area. (2) The regulations will be enforced by the Commander, Caribbean Sea Frontier, San Juan, P.R., and such agencies as he may designate. 33 C.F.R. § 204.234 (1979). At trial, Puerto Rico contended that the Navy’s use of this area for bombing and gunnery practice unreasonably interfered with the island’s food fishing industry, in violation of 33 U.S.C. § 3. In rejecting this claim, the district court ruled that: The Plaintiffs herein have presented absolutely no evidence that Defendant Navy has impermissibly or unilaterally expanded the areas authorized as a danger zone (33 C.F.R. § 204.234) ... The navigable waters contiguous to Defendant Navy’s weapons training range at Vieques are navigable waters of the United States, and they have been restricted in exactly the manner intended by law and regulations. 478 F.Supp. at 701. On appeal Puerto Rico argues that the district court failed to consider the needs of Vieques’ fishing industry, in disregard of the statutory requirement that the danger zone regulation not unreasonably interfere with or restrict the food fishing industry. We conclude, however, that the only question properly before the court was whether the Navy had complied with the danger zone regulation. As is apparent from the statutory language, the provision against unreasonable interference with the food fishing industry applies to the Secretary of the Army’s exercise of his authority to prescribe and regulate. Assuming that the Navy has acted in accordance with 33 C.F.R. § 204.234, to decide whether the Navy has unreasonably interfered with fishing would necessarily draw into question the validity of the regulation under the enabling statute, 33 U.S.C. § 3. Yet Puerto Rico has not named the Secretary of the Army as a defendant in this case. Thus, if we, or the district court, were to define a standard of reasonableness for 33 U.S.C. § 3 and apply it to the facts of this case, we would do so in the absence of the agency responsible for the administrafive determination that 33 C.F.R. § 204.234 comports with the statutory command. None of the record relevant to the formulation of this regulation is part of the record in this case. Nor, of course, has the Secretary had the opportunity, at trial or on appeal, to defend the propriety of the regulation. Had the district court ruled on whether 33 C.F.R. § 204.234 unreasonably interferes with the food fishing industry, we would vacate that ruling for the reasons stated above. We conclude, however, that the court’s decision is only a determination that the Navy has complied with 33 C.F.R. § 204.234. We need offer no opinion on this because Puerto Rico has not challenged it on appeal. Noise Pollution In its complaint, Puerto Rico contended that the Navy’s training activities generate “shock waves and excessive noise that unreasonably interfere with the health and welfare of residents of Vieques .... ” It sought to enjoin these activities as a violation of the Commonwealth’s criminal nuisance statute, P.R.Laws Ann. tit. 33, § 1365, alleged to be applicable to the Navy’s operations through Section 4 of the Noise Control Act, 42 U.S.C. § 4903(b) (the Act). The district court denied the re-quest for an injunction, ruling that the Act does not apply because the nuisance statute does not establish noise control “requirements” as that term is used in Section 4. 478 F.Supp. at 675. Despite this ruling, the court proceeded to consider the evidence and determined that the noise attributable to the Navy’s activities does not interfere with the quality of life on Vieques. Id. at 680. We conclude that the district court was without jurisdiction to entertain Puerto Rico’s claim. A careful reading of the Noise Control Act’s citizen suit provision, section 12, 42 U.S.C. § 4911, discloses that Congress expressly created a private cause of action only with respect to the enforcement of federal noise control requirements. Subsection (a) permits “any person,” including a state, to bring suit in federal district court against any federal agency that has violated a “noise control requirement.” That term is defined in subsection (f) by reference to other sections of the Act, all of which concern the granting of regulatory powers to the Administrator of the EPA or the Secretary of the Treasury, and the enforcement of regulations promulgated thereunder. Section 12 has no provision for citizens’ suits to enforce a federal agency’s duty to comply-with state and local requirements regarding the control and abatement of environmental noise. Thus, Puerto Rico’s claim, premised on a violation of state law, cannot be maintained under § 12 of the Act, 42 U.S.C. § 4911. In. the absence of an alternative basis in federal law, the unavailability of § 12 warrants dismissal of this state law claim for lack of jurisdiction because it is otherwise barred by sovereign immunity. See United States v. Testan, 424 U.S. 392, 96 S.Ct. 948, 47 L.Ed.2d 114 (1976); Larson v. Domestic & Foreign Commerce Corp., 337 U.S. 682, 69 S.Ct. 1457, 93 L.Ed. 1628 (1949). We recognize, however, that § 4, to the extent it subjects every federal agency to state noise control requirements, arguably permits suit against an officer of a federal agency for a violation of those requirements. If § 4 requires the Navy to comply with Puerto Rico’s criminal nuisance statute, this responsibility may be enforceable by an implied cause of action under § 4. We reach the latter question, however, only if we first determine that Puerto Rico’s nuisance statute establishes “requirements” that would trigger the application of § 4. The key issue, therefore, is the definition of “requirements.” As used in § 4 of the Noise Control Act, the term stands unexplicated by Congress or the courts. But the model from which § 4 was drawn, section 118 of the Clean Air Act (currently codified at 42 U.S.C. § 7604), has received intense scrutiny. Judicial interpretation of the term “requirement” as used in § 118, and Congress’ response to that interpretation, sheds considerable light on the definition of “requirements” as used in § 4. Section 118 of the Clean Air Act underwent its most important dissection at the hands of the Supreme Court in Hancock v. Train, 426 U.S. 163, 96 S.Ct. 2006, 48 L.Ed.2d 555 (1976). Two steps in the Court’s analysis are particularly apposite to the question before us. First, the Court’s reading of § 118’s legislative history disclosed that the various preliminary drafts and the committee reports used “requirements” interchangeably with “emission requirements” and “emission standards.” Id. at 188-89 & n.2, 96 S.Ct. at 2017 & n.2. Congress apparently understood “requirements” to refer to standards specifying the permissible emission levels for various point sources and pollutants. Though hardly conclusive, the court’s observation presents some evidence of the legislative use of the term in the pollution control context, and particularly in the drafting of the prototype for § 4. The second step in Hancock pertinent to our inquiry rested on the Court’s recognition of the close relationship between § 118 and § 304, the citizen suit provision of the Clean Air Act. 42 U.S.C. § 7604. “§ 118 establishes the duty of federal installations to comply with state ‘requirements,’ and § 304 provides the means of enforcing that duty in federal court.” 426 U.S. at 196, 96 S.Ct. at 2020. Section 304 restricts the area subject to enforcement by suit to emission limitations or standards, standards of performance, and compliance schedules. The Court concluded that the scope of the § 304 enforcement power defined the scope of the § 118 duties because “it seems most unlikely that in providing that a State might bring suit in district court to enforce the duties of federal installations under § 118, the Congress would not make all those duties enforceable .... ” Id at 197, 96 S.Ct. at 2021. We recognize a similar relationship between the “requirements” of § 4 and those of § 12 of the Noise Control Act. The primary objective in our attempt to clarify the term “requirements” is to ascertain Congress’ intent and § 12 contains the sole legislative definition of that term in the Act. More importantly, that definition occurs in the provision for private enforcement of the Act. Section 12, unlike § 304 of the Clean Air Act, does not allow for suit by a state to enforce a state pollution .control requirement. Thus, unlike the scheme of the Clean Air Act, § 12 does not define specifically which state requirements are incorporated in § 4. But it does permit a state to bring suit against a federal agency for violation of certain federal requirements. Considered together, the federal requirements enforceable under § 12 are the best evidence of the type of noise control requirement that Congress intended to be enforceable by suit against a federal agency- Section 12 authorizes suit by a state to enforce “any noise control requirement,” as defined in subsection (f). 42 U.S.C. § 4911(a). That definition in turn refers to several provisions of the Act which provide for (a) standards, rules or regulations controlling the noise emissions of motor carriers, railroads and aircraft, id. §§ 4916, 4917; 49 U.S.C. § 1431, (b) labelling regulations, 42 U.S.C. § 4907, and (c) noise emission standards applicable to specified domestic and imported products, id. §§ 4905, 4908. From these various provisions of the Act we can abstract the type of legal control contemplated by the statutory term “requirement.” The appointed agency establishes a standard that sets forth, specifically, the allowable intensity, duration and character of sounds from a certain type of source, and then measures the noise emissions of such sources against that standard. See 40 C.F.R. Parts 201-205. This type of control relies on relatively precise standards capable of uniform application to similar sources of sound. We conclude that when Congress used the term “requirements” in the Noise Control Act, it was in reference to regulations of this type. The final question is whether Puerto Rico’s criminal nuisance statute embodies the kind of “requirements” with which the Navy must comply pursuant to § 4. The statute broadly proscribes as a public nuisance: Anything which is injurious to health, or is indecent or offensive to the senses, or is an obstruction to the free use of property, so as to interfere with the comfortable enjoyment of life or property by an entire community or neighborhood, or by any considerable number of persons[.] P.R.Laws Ann. tit. 33, § 1365. Although the criminal nuisance statute