Opinion by Judge GOULD; Concurrence by Judge GOULD.
GOULD, Circuit Judge.
The Covingtons, who live across from a county dump, brought this citizen’s suit against Jefferson County and District 7 Health Department (“D7HD”), charging violations of the Clean Air Act (“CAA.”) and the Resource Conservation and Recovery Act (“RCRA” a.k.a. the Solid Waste Disposal Act (“SWDA”)). On cross-motions for summary judgment, the district court held that the Covingtons lacked standing to advance the CAA claim and had standing to assert the RCRA claims. The district court awarded summary judgment on these RCRA claims to Defendants. The parties cross-appealed. We have jurisdiction pursuant to 28 U.S.C. § 1291. We affirm in part, reverse in part, and remand for trial.
I
A
This dispute centers on a landfill directly across the street from the home of the Covingtons. When the Covingtons first bought their home, it was across the street from a gravel pit. In 1995 Jefferson County converted the gravel pit to a non-municipal solid waste landfill (“NMSWL”) for bulky waste. Jefferson County owned and operated the landfill at all relevant times. The landfill operation was approved initially and then overseen by District 7 Health Department according to an Operational Plan as required by Idaho regulations. The Operational Plan dealt with siting, operational requirements, and compliance with applicable Idaho regulations. Nonetheless, the Covingtons encountered problems with the landfill.
Under Idaho law, responsibility for regulatory oversight of solid waste facilities is split between the State Department of Environmental Quality (“DEQ”) and the District Health Departments (“DHDs”). The [634]*634division of responsibilities between these two organizations is defined in a Memorandum of Understanding (“MOU”).1
After the approval of the Operational Plan, D7HD inspected the landfill on twenty-five occasions. Although D7HD has been satisfied with Jefferson County’s follow-up to D7HD’s criticisms, D7HD has on occasion noted the disposal of improper material at the landfill and has commented that the landfill has not always had adequate cover and compaction, leading the landfill to fall under Idaho’s “open dump” definition.
The operation of the landfill generated a series of complaints by the Covingtons to Jefferson County and to D7HD. Although the landfill was inspected many times, no changes were made to address the Covingtons’ concerns. After giving notice to required governmental and private parties on May 17, 2001, the Covingtons brought a citizen suit against Jefferson County and D7HD on July 25, 2001, in the United States District Court for the District of Idaho. The suit claimed violations of CAA due to Jefferson County’s failure to comply with federal regulatory procedures designed to prevent the improper release of ozone-depleting substances. The suit also asserted three violations of RCRA: (1) that state regulations had been violated, thus violating RCRA; (2) that federal “open dump” criteria had been violated; and (3) that non-containerized liquid hazardous waste had been deposited at the landfill in violation of 42 U.S.C. § 6924.
After receiving notice of the Covingtons’ intent to sue on May 17, 2001, and shortly before the lawsuit was filed, the County and D7HD entered into a formal Plan of Correction on July 23, 2001. Shortly after the lawsuit was filed, the County and D7HD also entered into a revised Plan of Operation on July 31, 2001. The Plan of Correction and revised Plan of Operation included requirements to cap a portion of the landfill, and to prevent and monitor groundwater contamination. Neither the Plan of Correction nor the revised Plan of Operation deterred the Covingtons from filing suit.
After discovery for about ten months, all parties had moved for summary judgment. On cross motions for summary judgment, the district court held that the Covingtons did not have standing to bring the CAA claim but had standing to bring the RCRA claims. On the merits of the RCRA claims, the district court rejected the application of the state regulations, granted summary judgment to Appellees on the federal “open dump” criteria, and held that 42 U.S.C. § 6924 was only an enabling statute with no substantive prohibitions. The Covingtons appeal these decisions, save the ruling on standing under RCRA. D7HD cross-appeals the district court’s ruling on standing under RCRA. Thus the appeal and cross appeal bring all issues into play.
B
The Covingtons, on the cross motions for summary judgment, submitted evidence of serious problems at the landfill.2 The Covingtons’ affidavits and supporting documents gave evidence that the landfill mismanaged “white goods” (i.e., appli-[635]*635anees) by not ensuring that chlorofluoro-earbons (“CFCs”) were treated as required by federal law.3 The Covingtons raised these concerns before filing suit. The United States Environmental Protection Agency (“EPA”) also recognized a failure by the landfill to comply with federal record-keeping law. Although in 1999 the landfill began keeping records of CFC disposition of white goods, the records were generally incomplete.4
The Covingtons also offered evidence of fires at the landfill.5 In April 2000, the Covingtons observed a fire at the landfill and complained about it to Idaho’s DEQ. DEQ personnel in their report noted that treated or formed lumber had been burned. DEQ personnel also detected the smell of pesticides. The Covingtons observed another fire in March 2002. Alerted to this fire by the Covingtons, Jefferson County and DEQ personnel jointly responded and their report noted that the remains of the fire included items such as oil and water filters, and a metal bed frame. The County, in response, submitted evidence that this second fire was caused by an unauthorized intruder who accessed the landfill through an unlocked gate.
The Covingtons’ evidence also raised concerns about the type of waste accepted and disposed at the landfill. The Cov-ingtons presented evidence of improper disposal of biological substances. More specifically, the Covingtons submitted evidence of the disposal of household garbage, spilled grain, grass clippings, straw, manure, and even rotting bird and cow carcasses.6 It is undisputed that the discarded biological waste (including straw, manure, bird and cow carcasses, and spilled grain) can create methane gas as it decomposes, which is both explosive and creates a foul odor. Though there are means to monitor for methane gas, the landfill does not do so.
The Covingtons also submitted evidence of improper disposal of hazardous material. The evidence documented the disposal of containers with hazardous content warnings, appliances containing fuel and oh, and items leaking oil.7 DEQ personnel in one of their reports acknowledged that improper items were being disposed of at the landfill, including leaking car batteries, crushed cans with oil, and waste oil.
The Covingtons also presented evidence that insufficient cover was applied to the landfill. Cover refers to placing a layer of dirt or gravel over the waste so as to minimize fires, vectors (scavenging creatures such as birds, animals, and/or in[636]*636sects), and scavenger access. An adequate cover is fundamental for a landfill. Yet, at the landfill, food stuffs and carcasses were left uncovered for more than a week with mice and flies swarming over the uncovered items.8 The County conceded that it had no equipment to provide cover until 1997, and though a bulldozer was staged at the landfill, no one operated the bulldozer until 2000. D7HD reported at least three occasions in 1999 that the landfill lacked adequate cover.
The proffered evidence also demonstrated that, to a degree, the landfill was accessible to the public and did not have complete access control.9 The Covingtons often observed human scavengers in the landfill. In addition to the main gate, there were at least three routes to access the landfill that were not secured until after the Covingtons filed suit. And there was evidence that one of the fires might have been started by unauthorized persons who gained access to the landfill.
The Covingtons also presented evidence of their concern over possible groundwater contamination. But, while some evidence shows lead contamination at an up-gradient well, the Covingtons presented no evidence that this contamination came from the landfill. Moreover, the Appellees’ experts presented evidence, not contradicted by the Covingtons, that the groundwater contamination detected reflected the turbidity of the sample and that the sample was preserved with nitric acid. Repeated samples have not verified the contamination first detected.
II
D7HD raises a threshold concern about subject matter jurisdiction. Citizen suits under RCRA require proof of notice. For suits alleging present10 violations of RCRA, the plaintiff must provide notice to the relevant parties sixty-days before filing suit. See 42 U.S.C. § 6972(b)(1)(A). For actions alleging “contribution” to present or past violations of RCRA, ninety-day notice is required. Id. § 6972(b)(2)(A). Both notice provisions are jurisdictional: Absent compliance with a required notice provision, we lack subject matter jurisdiction to hear the RCRA claims. See Ascon Props. Inc. v. Mobil Oil Co., 866 F.2d 1149, 1160 (9th Cir.1989) (holding that the ninety-day notice requirement is jurisdictional); Hallstrom v. Tillamook County, 831 F.2d 889, 891 (9th Cir.1987) as amended 844 F.2d 598 (9th Cir.1987) (holding that the sixty-day notice requirement is jurisdictional). D7HD correctly asserts that more than sixty but less than ninety days elapsed between the Covingtons’ notice on May 17, 2001 and the filing of the complaint on July 25, 2001. D7HD therefore contends that we lack jurisdiction over the Covingtons’ “contribution” claims. Thus D7HD argues that, if we have no jurisdiction over § 6972(a)(1)(B) “contribution” claims, the entire RCRA claim must [637]*637fail because the Covingtons have not alleged a violation of RCRA under 42 U.S.C. § 6972(a)(1)(A), the only remaining viable citizen suit provision.
We reject D7HD’s argument. First, for the portion of the Covingtons’ suit that alleges current violations of RCRA under 42 U.S.C. § 6972(a)(1)(A), the suit satisfies the notice requirement because the Cov-ingtons provided the requisite sixty-day notice. Second, Congress provided an exception to the ninety-day notice period for “action[s] ... respecting a violation of sub-chapter III of this chapter:”11 42 U.S.C. § 6972(b)(2)(A). It is not surprising that Congress put aside notice requirements when plaintiffs allege violations of RCRA that involve presence of or mishandling of hazardous waste. The Covingtons made such a claim by alleging a violation of 42 U.S.C. § 6924, see infra Part VI, a provision within subchapter III of RCRA. See 42 U.S.C. Chapter 82 Table of Contents. The Second Circuit has held that a sub-chapter III claim regarding hazardous waste renders the required post-notice waiting period inapplicable -to all of a plaintiffs RCRA claims. See Dague v. City of Burlington, 935 F.2d 1343, 1352 (2d Cir.1991), rev’d in part on other grounds, 505 U.S. 557, 112 S.Ct. 2638, 120 L.Ed.2d 449 (1992) (stating that allegations of a subchapter III violation made § 6972(b) notice requirements inapplicable to entire “hybrid”12 suit so long as alleged RCRA- violations were “closely related,” such as claims that arise “from the operation of a single facility”); cf. Ascon, 866 F.2d at 1159-60 (declining to apply the § 6972(b)(2)(A) exception where hazardous waste was dumped before RCRA’s enaetment and could not constitute a violation of subchapter III).
We consider Dague persuasive and adopt its rule. We hold that neither the sixty-day nor ninety-day notice requirements under RCRA are applicable to nonsubchapter III claims in a hybrid suit so long as the non-subchapter III claims are related in time or location (e.g., that the violations all occurred at the same landfill) to any subchapter III claim. Under this rule, the Covingtons’ entire hybrid claim alleging a violation of subchapter III and other violations of RCRA at the same landfill is not subject to any notice provision. Accordingly, we have subject matter jurisdiction over the Covingtons’ hybrid RCRA claim, including the “contribution” claims.
Ill
We next examine whether the Covingtons have standing to advance claims under CAA and RCRA. Each statute requires a distinct analysis. We review the district court’s standing determinations de novo. Hall v. Norton, 266 F.3d 969, 975 (9th Cir.2001).
Article III of the Constitution requires that a plaintiff have standing before a case may be adjudicated. This constitutional requirement ensures that litigants have an incentive to develop their case so that a court can correctly address- the issues presented. To satisfy Article III a plaintiff must show (1) “ ‘an injury in fact’ that is (a) concrete and particularized and (b) actual or imminent ...; (2) [that] the injury is fairly traceable to the challenged action of the defendant; and (3) it is likely, as opposed to merely speculative, that the [638]*638injury will be redressed by a favorable decision.”13 Hall, 266 F.3d at 975 (quoting Friends of the Earth, Inc. v. Laidlaw Envtl. Servs. (TOC), Inc., 528 U.S. 167, 180-81, 120 S.Ct. 693, 145 L.Ed.2d 610 (2000)). The Covingtons, who invoke federal jurisdiction, have the burden of establishing all three elements. See Lujan v. Defenders of Wildlife, 504 U.S. 555, 561, 112 S.Ct. 2130, 119 L.Ed.2d 351 (1992). The district court held that these elements were satisfied for the RCRA claims but not for the CAA claim. We examine these rulings in turn.
We first address whether the Covingtons had standing for their RCRA claims. Appellees Jefferson County and D7HD first dispute that the Covingtons have satisfied the injury requirement. We disagree. The Covingtons live just across the road from the landfill. If the landfill is not run as required by RCRA, the Covingtons are directly confronted with the risks that RCRA sought to minimize: Fires, explosions, vectors, scavengers, and groundwater contamination, if such occur, threaten the Covingtons enjoyment of life and security of home.14 Violations of RCRA increase the risks of such injuries to the Covingtons. Such risks from improper operation of a landfill are in no way speculative when the landfill is your next-door neighbor. The Covingtons’ factual showing of fires, of excessive animals, insects and other scavengers attracted to uncovered garbage, and of groundwater contamination, evidence a concrete risk of harm to the Covingtons that is sufficient for injury in fact. See, e.g., Hall, 266 F.3d at 976 (holding “evidence of a credible threat to the plaintiffs physical well being from airborne pollutants” sufficient to satisfy the injury requirement) (emphasis added); Churchill County v. Babbitt, 150 F.3d 1072, 1078 (9th Cir.1998), as amended, 158 F.3d 491 (9th Cir.1998) (holding that claimant need only establish “the reasonable probability of the challenged action’s threat to [his or her] concrete interest”) (emphasis added) (internal quotation marks omitted).15
The Covingtons also submitted evidence of RCRA violations affecting their enjoyment of their home and land. For example, they alleged that the violations caused them to suffer from watering eyes and burning noses. Moreover, even if the only injuries alleged by the Covingtons were threats to the aesthetic and recreational enjoyment of their property, these harms occasioned by RCRA violations in context are sufficient to satisfy the injury in fact requirement: See Sierra Club v. Morton, 405 U.S. 727, 739, 92 S.Ct. 1361, 31 L.Ed.2d 636 (1972); Ecological Rights Found. v. Pac. Lumber Co., 230 F.3d 1141, 1149 (9th Cir.2000).
[639]*639Appellees Jefferson County and D7HD misunderstand the standing inquiry, and by their argument seek to convert the standing issue into a question of whether there have been violations of RCRA. This misses the point of standing: the relevant inquiry here is not whether there has been a breach of RCRA by the County or the Health Department, but whether Appellees’ actions have caused “reasonable concern” of injury to the Covingtons. See Laidlaw, 528 U.S. at 188, 120 S.Ct. 693. “[Environmental plaintiffs adequately allege injury in fact when they aver that they use the affected area and are persons for whom the aesthetic and recreational values of the area will be lessened by the challenged activity.” Id. (internal citations and quotations omitted) (emphasis added). To meet the injury in fact requirement for standing, the Covingtons need not show that they will prevail on their challenge asserting that there has been a violation of RCRA; they need only show that the conduct they challenge sufficiently injures them. The Covingtons have introduced sufficient evidence to satisfy the injury in fact requirement.
Appellees also dispute causation and redressability. We disagree. Jefferson County operates the landfill, thus any violation of RCRA is directly caused by the County, and any violation can be redressed by requiring the County’s compliance with RCRA or by creating a credible deterrent against future violations via the imposition of fines. Laidlaw, 528 U.S. at 185-86, 120 S.Ct. 693.
There is also causation and redressability as to D7HD. D7HD, in its cross-appeal contesting RCRA standing, argues that it has only regulatory oversight and gives technical guidance, but that it is not responsible for enforcement or corrective action. This argument, however, is not borne out by the record. Under the February 1, 2000 MOU between the DHDs and the DEQ, the DHDs are responsible for approving applications for the operation of non-municipal solid waste facilities, issuing conditional use permits, and providing regulatory oversight of the operations of NMSWFs.16 This shows that the D7HD could have suspended the County’s operation of the landfill, issued a more stringent conditional use permit, or had more frequent or more rigorous inspections to ensure regulatory compliance. If D7HD declined to take any of these regulatory actions, such inaction, which is correctable by court order or sanction, meets the causation and redressability elements of standing.17
[640]*640D7HD argues, however, that DEQ, not a DHD, is responsible for “enforcement and corrective action.” We are not persuaded. DEQ is the “lead agency” for corrective action, but that does not preclude corrective actions by another agency such as D7HD. D7HD is not precluded from initiating corrective action as part of its regulatory oversight18 and allowing the DEQ to lead once the action has started. Moreover, D7HD had the ability and the power to implement a “Plan of Correction,” as it did here. That D7HD did not use this and the other coercive tools at its ready disposal satisfies the causation requirement.
Second, D7HD argues that there is no redressability because new Idaho regulations render any remedy moot. D7HD asserts that the cover regulations are now more stringent than federal regulations. This argument fails. A RCRA claim against those who “contribute” to violations can be brought for prior violations. The new regulations are, under Idaho law, no more stringent than federal requirements. See Part IV infra. D7HD also maintains that it has no remaining role in solid waste management under the new regulations and that, if D7HD does not have a role in solid waste management, there is no remedy that can redress the prior and ongoing violations. But D7HD cannot so easily distance itself from any failures of the landfill to satisfy RCRA. The DHD’s role did not change as a result of the new regulations: The division of responsibility remains as outlined in the 2000 MOU. See www.deq.state.id.us/waste/solid_waste/ landfills.htm# roles. Idaho law continues to authorize the DHDs to “ascertain that operations standards are met, prepare and/or adopt technical guidance, review and recommend approval of alternative operating ... requirements.” Idaho Code § 39-7406 (2003). Because the D7HD retains the same power as before the new regulations, it follows that D7HD retains the ability to require changes ensuring compliance with RCRA. No sleight of hand can deal D7HD out of this case, given its important statutory role to regulate solid waste disposal in Idaho. We hold that the asserted injury of the Covingtons is re-dressable as to D7HD.
Because the Covingtons satisfied all necessary elements of standing to support their RCRA claims against Jefferson County and against D7HD, we affirm the district court’s decision that the Coving-tons have standing under RCRA.
We next address whether the Covingtons have standing to advance a claim under the Clean Air Act. The Covingtons claim that Jefferson County violated the CAA by not following federal procedures to account for removal or recapture of CFCs and other ozone-depleting substances before disposal or recycling. See 42 U.S.C. § 7671g; 40 C.F.R. §§ 82.154(a); 82.156(f); 82.166(i), (m). The district court held that the Covingtons lacked standing, reasoning that there was no evidence of a leak of ozone-depleting substances,19 and [641]*641that the CAA violations caused no injury to the Covingtons. Because part of the Covingtons’ claim stems from procedural irregularity,20 the redressability and imminence of injury requirements are relaxed. See Hall, 266 F.3d at 976, 977.21
The evidence of leakage of white goods provided by the Covingtons is sufficient to show injury in fact because the failure to comply with CAA has increased the risk of harm to the Covingtons’ property; The Covingtons have observed liquids' leaking from the white goods and they fear that this liquid will contaminate their property. From this, the Covingtons’ enjoyment of their property is diminished by the attested leaks. This analysis is parallel to our analysis of injury in fact for the RCRA violations. A credible threat of risks to their home yields a loss of enjoyment of property. That is enough for injury in fact for the CAA claims.
There is also causation: Failure of the landfill to follow CAA procedure allowed CFCs and other ozone-depleting substances to be released in the landfill, instead of being recaptured or properly removed. If the CAA regulation had been followed, no liquids would have leaked from the white goods. Or if liquid had leaked, these violations of federal law would have been documented. Redressa-bility is satisfied, as with the RCRA violations, by the fines and penalties applicable for violations of CAA. Laidlaw, 528 U.S. at 185-86, 120 S.Ct. 693. Such CAA fines and penalties can cause Jefferson County to bring the landfill into compliance with the CAA. We conclude that the Covingtons have standing to bring the CAA claim.
IV
The Covingtons next argue that the district court erred by disregarding potentially applicable Idaho regulations on solid waste management when analyzing whether there had been a violation of RCRA.22 Under Ninth Circuit precedent, it [642]*642is a violation of RCRA if a regulated entity-does not comply with the state-selected implementation of the RCRA regime so long as the state standard is not “more stringent” than the federal criteria. See Ashoff v. City of Ukiah, 130 F.3d 409, 411-12 (9th Cir.1997).
In Ashoff, we held that “if state standards ‘become effective pursuant to’ RCRA, a citizen can sue in federal court to enforce the standard” because “[t]he federal criteria give the state standards legal effect under federal law.” Id. at 411. “Thus, a citizen suit could be brought under RCRA for non-compliance with the state selected alternative” so long as the state standards do not “exceed the federal criteria.” Id. at 411-12. If “a state elects to create more stringent standards, nothing in RCRA gives them legal effect. Their legal effect flows from state law.” Id. at 412.
Moreover, Ashoff also held that it is also a violation of RCRA if a landfill violates the RCRA “open dump” criteria, and the landfill would be subject to a citizen suit, notwithstanding EPA approval of a state program. Id. at 411 n. 3. The Ashoff court rejected the theory that “once the EPA approves a state program, RCRA no longer authorizes citizen suits under Subtitle C or D.” Id. at 411 (internal quotation marks omitted). This holding follows the EPA’s interpretation of RCRA. See id. at 411-12 & n. 3 (citing 61 Fed.Reg. 2584, 2593 (Jan. 26, 1996), 49 Fed.Reg. 48300, 48304 (Dec. 12, 1984), 45 Fed.Reg. 85016, 85021 (Dec. 24, 1980)).
Thus, under settled law, if the Idaho standards at issue here are not “more stringent” than the federal criteria under RCRA, a violation of either the state or the federal standards is a violation of RCRA for which a citizen may bring suit. Id.
The district court initially erred by not conducting a stringency analysis under Ashoff to determine whether violation of state solid waste management regulations could serve as a violation of RCRA. The district court rejected the Covingtons’ attempt to prove violations of RCRA by showing that Jefferson County violated state regulations. Without a discussion or evaluation of the applicability of Ashoff, the district court held that “[t]he Court rejects the Covingtons’ reliance on alleged violations of state standards to support their claim that the County violated the federal regulations.” The district court did not apply the rule set forth in Ashoff.
For several of Idaho’s landfill requirements, this error was not harmless. Idaho law prohibits the creation of solid waste disposal regulations that would “impose conditions or requirements more stringent or broader in scope than the referenced RCRA regulations_” Idaho Code § 39-7404 (2003). The Appellees Jefferson County and D7HD acknowledge this statutory limitation, but argue nonetheless that the state regulations cited by the Covingtons were “more stringent than the federal regulations.” Doubtless this argument is advanced in the hope of avoiding D7HD’s prior concessions that there were violations of the applicable Idaho regulations by the landfill. Appellees apparently contend that the state regulations that have been violated are ultra vires. We disagree. Comity considerations counsel against lightly concluding that the regulations were promulgated in contravention of the Idaho statute that authorized their promulgation. After assessing the terms of the Idaho regulations and the federal criteria that they, by Idaho law, may not exceed, we conclude that the relevant state regulations are lawful because they are not more stringent than the federal standards. To elaborate, we will dis[643]*643cuss the relevant Idaho regulations in turn.
The first regulation that we address provides a “cover” requirement. Former IDAPA 58.01.06.006.03 (1992).23 Appellees claim that because RCRA requires “periodic” cover, Idaho’s requirement of six-inches of cover at the end of each operating day is more strict. The cover requirements can be evaluated in two dimensions: frequency and amount. As to frequency, the federal standard of RCRA defines periodic cover as cover applied at the “end of each operating day.” 40 C.F.R. § 257.3-6. Idaho’s cover requirement also applies at the end of each operating day. There is no difference on the required frequency of cover. As to amount of cover, the RCRA regulations found in 40 C.F.R. § 257.3-6, applicable to solid waste facilities generally, do not set a minimum depth of cover, though they require cover “in such a manner as to reduce the risk of fire and to impede vectors access....” Id. In contrast, Idaho dictates that six inches of cover be applied. We conclude that this regulation is not more stringent than RCRA, but rather is the “manner” that the state determined was required to reduce fire risk and impede vector access. Six inches is Idaho’s implementation of a uniform standard for the amount of cover needed to reduce fire and impede vector access. Because the Idaho cover regulations are no more stringent than the RCRA criteria for cover, the district court should have adopted them as a relevant standard for a RCRA violation. See Ashoff, 130 F.3d at 411-12.
The district court erred in granting summary judgment because the district court disregarded the violations of Idaho’s cover regulations that were supported by the Covingtons’ proof. That error was significant because a D7HD Health Specialist found three violations of the Idaho cover requirement. These documented violations defeat the district court’s summary judgment on the claim that the landfill operation offended Idaho’s cover requirements, and thus violated RCRA, because disputed issues of material fact remain.
We next turn to the Idaho open burning regulations. IDAPA §§ 58.01.01.603.01; 58.01.06.010(d)(ii) (2002). Open burning at landfills is generally prohibited, but the regulations make certain limited exceptions if the burning is infrequent and the materials are agricultural wastes, silvicultural wastes, land clearing debris, diseased trees, or debris from emergency cleanup operations. IDA-PA 58.01.06.010(d)(ii). These restrictions are no stricter than the federal criteria that generally ban open burning with limited exceptions for “infrequent burning of agricultural wastes in the field, silvicultural wastes for forest management purposes, land-clearing debris, diseased trees, debris from emergency clean-up operations, and ordnance.” 40 C.F.R. § 257.3-7.
Idaho’s open burning criterion should have been examined by the district court because there are disputed issues of material fact regarding whether it had been violated. There is evidence of at least two fires at the dump. The first fire involved the burning of treated wood, which does not fall within an exception to the prohibition on open burning. The second fire included metal filters and a metal bed frame which are also not included in either the federal or the state exceptions. Because neither of these fires fall within the state’s listed exceptions, they violated [644]*644Idaho’s open burning prohibitions. IDA-PA §§ 58.01.01.603.01; 58.01.06.03.k (2002). Although the Appellees contend that the second fire was started by someone else, the Covingtons presented evidence that the fire occurred on the dump, and this is sufficient to create an issue of fact on the landfill’s responsibility.24 Further, the County’s defense to the second fire does not give defense for the first fire, nor for the third fire that the Covingtons witnessed. Summary judgment on this claim was improper because issues of disputed material fact remained.
The Covingtons also asserted violations of Idaho’s criteria for groundwater contamination and the prevention of explosive gas, but they fail to cite any specific state criteria that would support them argument. As such, there are no regulations against which the Ashoff analysis can be performed. The district court properly dismissed on summary judgment the Covingtons’ claims of groundwater contamination and explosive gas based on Idaho regulations.
We conclude that the district court erred in not conducting an Ashoff stringency analysis, that Idaho’s cover and open burning requirements are no stricter than the federal requirements of RCRA, and that there is evidence of past violations of Idaho’s cover and open burning requirements that should have been sufficient to allow the Covingtons to proceed to trial. Our analysis shows that the Covingtons presented sufficient evidence of violations of the state standards under Ashoff to prove a claim under RCRA. The district court erred in granting summary judgment against the Covingtons on these two grounds.
V
We next address whether the district court properly granted summary judgment to Appellees based upon the asserted violations of RCRA’s sanitary landfill criteria. RCRA authorizes citizen suits for violations of the federal sanitary landfill criteria, 40 C.F.R. § 257.3 et seq., even if the EPA approved the state’s program. See Ashoff v. City of Ukiah, 130 F.3d 409, 411 & n. 3 (9th Cir.1997). The Covingtons argue that Appellees have directly violated several provisions of the federal criteria. The district court awarded summary judgment to Appellees on each of these provisions. For each asserted violation of these federal regulations, we examine whether the district court correctly granted summary judgment.
The Covingtons claim that the landfill contaminated their drinking water. Under the applicable regulation, 40 C.F.R. § 257.3-4, “[a] facility or practice shall not contaminate an underground drinking water source beyond the solid waste boundary.” The district court correctly granted summary judgment to Appellees on this claim. It is uncontested that the only contaminants found were located up-gradient from the landfill and that the contaminant (lead) was introduced by the testing procedure. While the risk of groundwater contamination is sufficient to give the Cov-ingtons standing, there is inadequate evidence of groundwater contamination to survive summary judgment. We conclude that evidence of contamination of groundwater up-gradient from the landfill is not [645]*645probative that the landfill has corrupted the water down-gradient from it. We therefore affirm the district court’s grant of summary judgment.
The Covingtons next claim that the Defendants violated RCRA’s cover requirement. As discussed supra, the applicable federal criteria require “periodic cover,” defined as “the application and compaction of soil or other suitable material over disposed solid waste at the end of each operating day or at such frequencies and in such a manner as to reduce the risk of fire and to impede vectors access to the waste.” 40 C.F.R. § 257.3-6. The district court held that this criterion was met because “[t]he only evidence in the record shows that the County applied ‘periodic application of cover material.’ ” We disagree.
The district court focused too narrowly on the term “periodic” as the required frequency, without giving due weight to the fact that the federal regulatory language stresses cover “at the end of each operating day,” and we interpret this regulation to mean that daily cover is the minimum required under federal law. Cf. Revisions to Criteria for Municipal Solid Waste Facilities, 62 Fed.Reg. 40708, 40709-10 (July 29, 1997).25 Under a proper reading of the daily cover requirement, there is a genuine issue of fact whether this requirement has been met. A D7HD Health Specialist noted in inspection reports at least three times when daily cover was not applied. The Covingtons presented evidence of rotting bird and cow carcasses that lay uncovered for more than a week. If this evidence is credited at trial, a rational trier of fact could find for the Covingtons on this issue. In light of our determination on the correct legal standard requiring daily cover, the district court erred in granting summary judgment on the cover requirement.
C
The Covingtons next claim that Appellees violated RCRA’s open burning prohibition. The controlling regulation, 40 C.F.R. § 257.3-7, prohibits a landfill from “engaging] in open burning of residential, commercial, institutional or industrial solid waste.” The Covingtons’ evidence of fires, discussed above, which included the burning of treated wood and metal, contradicts the district court’s conclusion that “there is no evidence that the two incidents of burning that occurred violated the federal regulation.” Because the burnings discussed above do not fall within an exception in the federal criteria, and it is not permissible at such a landfill to burn treated wood and metal, the Covingtons have presented sufficient evidence to have survived summary judgment.
D
The Covingtons next claim that Appellees violated RCRA’s requirement prohibiting the buildup of explosive gases. The applicable regulation, 40 C.F.R. § 257.3-8, limits the allowable concentration of explosive gases to a maximum that must be less than 25% of the lower explosive limit (i.e., the point at which explosion may occur) for the gases in facility structures, and less than 25% of the lower explosive limit at the property boundary. Jefferson County and D7HD argue that the Covingtons cannot prove the existence of any explosive gas, much less explosive [646]*646gas in the quantities prohibited by RCRA. The Covingtons concede that they cannot prove the existence of explosive methane gas, nor that the RCRA limit was exceeded. But the Covingtons contend that the reason they cannot provide evidence of the existence of methane gas is precisely because the Appellees did not monitor the landfill property for such gases.26
A landfill that accepts waste products that can produce explosive gases, while not monitoring for such gases, places the public at risk. Such a landfill should not be able to avoid RCRA’s requirements by asserting that a plaintiff lacks evidence of explosive gases. Individuals in the position of the Covingtons have no ability whatsoever to monitor gases within the landfill’s structures, and have little ability to monitor gases at the landfill’s property boundaries. If we were to accept Appellees’ argument that thé Covingtons cannot prove dangerous concentrations of explosive gas, any landfill operator could elect not to monitor its gases and, absent a plaintiffs trespass and covert installation of monitoring and telemetry equipment, thereby ensure that a plaintiff would be unable to prove a RCRA violation from concentration of dangerous gases. Even in a case where concentrations of explosive gas presented grave dangers to the public, a plaintiff would be unable to prove a violation of the explosive gas concentration máximums solely because the landfill had failed to monitor for such a violation. To avoid this inequitable result, we hold that if a plaintiff establishes (1) that a landfill accepts wastes that routinely may produce explosive gas and (2) that the landfill fails to monitor for such gas, then the plaintiff is entitled to a rebuttable presumption that the explosive gas requirement of 40 C.F.R. § 257.3-8 has been violated. The burden then rests on the defendant landfill to prove that the quantity of explosive gases did not exceed the RCRA threshold.27 Applying this presumption, we conclude that the Covingtons presented sufficient evidence to raise a presumption of dangerous gas concentration, and thus a genuine issue of fact whether the regulatory prohibitions were violated. The Covingtons presented evidence demonstrating that the landfill routinely accepts biological wastes that can produce methane gas, and that Jefferson County and D7HD did not establish a reasonable system to monitor the concentration of any explosive gas. At trial, the same presumption may arise upon the same showing by the Covingtons. Jefferson County and D7HD may then present evidence to rebut the presumption, and if the presumption is rebutted the burden of proof will be on the Covingtons to make their case that dangerous gas concentrations exceeded regulatory limits.
E
The Covingtons claim a violation of RCRA’s open access requirement. As required by 40 C.F.R. § 257.3-8, a facility must prevent the public’s exposure to po[647]*647tential health and safety hazards by prohibiting uncontrolled access to a disposal site. The district court held that “uncon-tradicted evidence shows that access to the landfill is controlled at least to some extent and there is no evidence that the extent of public access allowed is exposing the public to potential health and safety hazards.” There are two parts to this holding: (1) that there is some control of access; and (2) that the there is no evidence of public hazard. We reject the district court’s analysis on both counts.
First, that some access may be controlled does not mean that all access is controlled. The Covingtons introduced evidence to show that there is (or was) easy access to the landfill and that this access created a public hazard. The Covingtons submitted evidence that there were several access routes to the landfill, including a gate that was left open on at least two occasions, the absence of a fence on the southern edge of the landfill until the summer of 2001, and an unsecured gate on the northeast corner of the landfill until March 2002. The evidence submitted by the Cov-ingtons, taken as a whole, is sufficient to permit a rational factfinder to conclude that parties who wanted to enter the landfill did so with impunity notwithstanding “fences, earthen berms, signage, locked gates and personnel.” A rational trier of fact, crediting the Covingtons’ evidence, and giving them all reasonable inferences, could find that human scavengers were able to access the landfill after the main gate was closed, that a D7HD inspector could access the landfill when the landfill was closed, and ultimately that Jefferson County and D7HD violated RCRA’s access restrictions.
Second, the Covingtons’ evidence was sufficient to support a conclusion that access created a public hazard. For example, the County urges that the second fire was caused by an unauthorized person who entered the landfill with solid waste to burn, and after igniting the materials, left the landfill. This is sufficient evidence of uncontrolled access for the Covingtons’ claim on this ground to survive summary judgment. We reverse the district court’s summary judgment dismissing the claim that uncontrolled access offended the federal regulation.
* * *
In conclusion, we affirm the district court’s grant of summary judgment on the Covingtons claim of contamination of the underground drinking water. We reverse the district court’s grant of summary judgment on the Covingtons’ claims of violations of RCRA’s regulatory criteria regarding cover, open burning, explosive gases, and uncontrolled access.
VI
Finally, we address whether the district court erred when it ruled that 42 U.S.C. § 6924 is merely an enabling statute, containing no substantive requirements. The district court, citing Jones v. Inmont Corp., 584 F.Supp. 1425, 1431 (S.D.Ohio 1984), held that 42 U.S.C. § 6924 only authorizes the EPA to promulgate regulations. We disagree. The Jones court rested its interpretation of § 6924 on the version of the statute that existed on April 26, 1984. At that time, § 6924 contained only one provision: the section that is currently labeled § 6924(a).28
[648]*648The provision then was an enabling clause. However, on November 8, 1984, Congress enacted the Hazardous and Solid Waste Amendments of 1984, Pub.L. No. 98-616 (1984), which significantly expanded § 6924. The amendments added substantive provisions, including that six months after them enactment “the placement of bulk or noncontainerized liquid hazardous waste ... (whether or not absorbents have been added) in any landfill is prohibited.” See Pub.L. 98-616, Title II, Sec. 201(c) codified at 42 U.S.C. § 6924(c)(1) (2003) (emphasis added). This is substantive law. See Vasquez v. Hillery, 474 U.S. 254, 282 n. 15, 106 S.Ct. 617, 88 L.Ed.2d 598 (1986) (stating that a “substantive law ... defines particular substantive claims for relief’); Meadows v. Dom. Rep., 817 F.2d 517, 524 (9th Cir.1987) (“Substantive law is defined as ‘[t]he basic law of rights and duties’ ....”) (citing Black’s Law Dictionary 1281 (5th ed.1979)); Guam v. Okada, 694 F.2d 565, 569 (9th Cir.1982) (stating that in the context of criminal law, “substantive law defines those acts which are considered crimes and establishes the punishment to be imposed upon violators”). If a statute proscribes conduct, then we consider it substantive, because it imposes a duty upon all not to engage in that conduct.
In this case there is still more. Congress intended a scheme where certain disposals of liquid hazardous waste were prohibited whereas other disposals of liquid hazardous waste were permissible within a regulatory framework. Compare 42 U.S.C. § 6924(c)(1) (2003) (prohibiting the placement of bulk or noncontainerized liquid hazardous waste) with id. at § 6924(c)(2) (requiring the Administrator [649]*649to promulgate regulations regarding the disposal of containerized liquid hazardous waste). This comparison reinforces our conclusion that Congress prohibited the placement of noncontainerized hazardous waste in landfills and that a citizen can sue to enforce that prohibition. See 42 U.S.C. § 6972. To ignore Congress’s plain intent and to refuse to enforce the prohibition in § 6924(c)(1) would undermine the regulatory regime created by Congress.
Summary judgment for the Appellees on this claim was error.
VII
We affirm the district court that the Covingtons had standing for the RCRA claims. We reverse the district court’s holding that the Covingtons did not have standing for the CAA claims. We affirm in part and reverse in part the district court’s grant of summary judgment on the claimed violations of state and federal sanitary landfill requirements, as set forth specifically above. We reverse the district court’s holding that 42 U.S.C. § 6924(c)(1) is not substantive. We remand for further proceedings consistent with our opinion.
Costs on appeal are awarded to the Cov-ingtons and these costs shall be borne equally by Appellees Jefferson County and D7HD.
AFFIRMED IN PART, REVERSED IN PART, AND REMANDED.