Appellants, Southern Pacific Transportation Company (“SPTC”), and Thomas M. Tompkins appeal the district court’s order granting summary judgment for Public Service Commission of Nevada (“PSC”). Appellants argue that PSC regulations requiring rail carriers to obtain an annual permit prior to loading, unloading, transferring or storing hazardous material on railroad property within the state are preempted by the Hazardous Materials Transportation Act and the Federal Railroad Safety Act. They also argue that the district court failed to give sufficient deference to an inconsistency ruling by the United States Department of Transportation (“DOT”) and that the PSC regulations violate the Commerce Clause. We reverse.

Congress enacted the Hazardous Materials Transportation Act, 49 U.S.C. App. § 1801, et seq. (“HMTA”), in 1975 to replace a patchwork of state and federal laws and regulations concerning hazardous materials transport with a scheme of uniform, national regulations. Jersey Cent. Power & Light Co. v. Lacey, 772 F.2d 1103 , 1112 (3d Cir.1985), cert. denied, 475 U.S. 1013 , 106 S.Ct. 1190 , 89 L.Ed.2d 305 (1986); S.Rep. No. 1192, 93rd Cong., 2d Sess. 1 *354 (1974), U.S.Code Cong. & Admin.News 1974, 7669. The HMTA commences with a congressional declaration of policy:

49 U.S.C.App. § 1801. Pursuant to its delegated authority, the DOT has enacted a series of comprehensive regulations governing the transportation of hazardous materials, including explosives, by rail and highway. 49 C.F.R. pts. 171-179 (“HMR”).

In January, 1986, the PSC adopted a series of regulations, Nevada Administrative Code §§ 705.310 to 705.380, to ensure that loading, unloading, transfer or temporary storage of hazardous materials on a railroad’s property be accomplished in as safe a manner as practical. Nev. Rev. Stat. § 223.064 Statement, P.S.C. Gen. Sess. Jan. 27, 1986. “The Commission’s goal in adopting [these regulations] was to establish a procedure for consistent statewide evaluation of potential on-and-off loading and temporary storage sites for the materials listed in the regulation.” Id.

The Nevada regulations require a carrier to obtain an annual permit prior to loading, unloading, transferring or storing certain hazardous materials on railroad property. Applicants are required to submit:

Nev. Admin. Code § 705.330 . The application also requires a $200 fee. Id.

In evaluating an application, PSC considers:

Nev. Admin. Code § 705.340 . PSC is required to give notice of any application for a permit or renewal at least 30 days before the date on which it intends to take action. Nev. Admin. Code § 705.370 .

Upon a showing of “compelling need,” PSC may issue a temporary permit which is valid while the application for an annual permit is pending. Nev. Admin. Code *355 § 705.350.1 . However, this provision is of concern primarily to carriers seeking their initial permit. Others seeking to renew their permits can ensure that they do not expire prior to a determination on their applications by submitting a complete application for renewal at least 60 days before the expiration of their permits. Nev. Admin. Code § 705.350.4 .

A permit may be suspended or revoked if a carrier violates the terms of the permit, if suspension or revocation is necessary to protect against risks to life or property, or if the permit was issued on the basis of false, fraudulent or misleading representations or information. Nev. Admin. Code § 705.360 .

On September 15, 1986, PSC instituted criminal proceedings in the Storey County Justice Court against Thomas Tompkins, SPTC’s supervisor of rail operations, for storing class A explosives at SPTC’s Hafed, Nevada siding without a permit. Additional proceedings were later instituted with regard to SPTC’s storage of explosives at its Wabuska siding.

On October 21, 1986, following the procedures set forth in 49 C.F.R. § 107.203 , SPTC applied for an administrative ruling on the question of whether the Nevada regulations were preempted by the HMTA. On June 23,1987, the Director of the Office of Hazardous Materials Transportation issued Inconsistency Ruling IR-19, finding Nev. Admiin. Code §§ 705.310 through 705.-370 to be inconsistent with the HMTA and, therefore, preempted. PSC filed an appeal of IR-19 with the Administrator of the Research and Special Programs Administration, pursuant to 49 C.F.R. § 107.211 . On April 1, 1988, the Administrator issued a decision affirming the inconsistency ruling.

On September 19, 1986, plaintiffs SPTC and Thomas M. Tompkins (collectively “SPTC”) filed suit against defendants PSC, its individual commissioners, and the district attorneys of Storey County and Lyon County, Nevada (collectively “PSC”), seeking declaratory judgment and injunctive relief against the Nevada regulations. The parties filed cross motions for summary judgment. On September 28, 1988, summary judgment was entered in favor of PSC and against SPTC. Timely notice of appeal was filed by SPTC on October 24, 1988.

We review a grant of summary judgment de novo. Kruso v. Int’l Tel. & Tel. Corp., 872 F.2d 1416 , 1421 (9th Cir.1989). We must determine, viewing the evidence’ in the light most favorable to the nonmoving party, whether there are any genuine issues of material fact and whether the district court correctly applied the relevant substantive law. Tzung v. State Farm Fire & Casualty Co., 873 F.2d 1338, 1339-40 (9th Cir.1989).

III

The HMTA expressly preempts state or local regulations inconsistent with federal law:

49 U.S.C.App. § 1811(a). Such regulations are “inconsistent” when (1) compliance with both the state or local regulation and the HMTA or DOT regulation is impossible, or (2) the state or local regulation is an obstacle to the accomplishment and execution of the HMTA or DOT regulation. 49 C.F.R. § 107.209 .

In this case, the district court held that the Nevada regulations were not inconsistent with the HMTA and HMR. However, SPTC argues that the district court erred by failing to accord sufficient deference to the inconsistency ruling issued by the DOT. We agree.

The DOT found that its regulations and the Nevada regulations address many of the same matters. For instance, it found that several of its own regulations already address storage incidental to the transportation of hazardous materials, the primary *356 focus of the Nevada regulations. Additionally, the Nevada regulations address other matters related to the transportation of hazardous materials. Because the Nevada regulations address matters already covered by the federal regulations, impose substantial burdens on applicants, and create the risk of confusion, conflicts, and delays, the DOT determined that they were inconsistent with the federal regulations. See DOT Research and Special Programs Administration, Inconsistency Ruling No. IR-19, Notice of Decision on Appeal, at p. 8 (April 1, 1988).

The DOT’s inconsistency rulings are not binding on the courts. However, we generally “accord deference to the construction of a statute by those charged with its administration.” State of Cal. ex rel. Water Resources Bd. v. FERC, 877 F.2d 743, 745 (9th Cir.), cert. denied, — U.S. -, 110 S.Ct. 537 , 107 L.Ed.2d 535 (1989). In fact, the Supreme Court has held that

Udall v. Tallman, 380 U.S. 1, 16 , 85 S.Ct. 792, 801 , 13 L.Ed.2d 616 (1965); see also Aluminum Co. of America v. Central Lincoln Peoples’ Util. Dist., 467 U.S. 380, 389-90 , 104 S.Ct. 2472, 2479-80 , 81 L.Ed.2d 301 (1984) (“Under established administrative law principles, it is clear that the Administrator’s interpretation of the [statute] is to be given great weight.”).

The district court failed to accord sufficient deference to the DOT’s construction of its own regulations. As the DOT’s inconsistency ruling noted, “transportation” subject to the HMTA includes “any movement of property by any mode, and any loading, unloading, or storage incidental thereto.” 49 U.S.C.App. § 1802(6). Consequently, numerous HMR provisions address loading, unloading, and storage. For instance, with regard to loading and unloading:

See 49 CFR §§ 174.16-174.840 . Additionally, with regard to temporary storage:

See 49 CFR §§ 173.314-174.750 .

At least one federal court has recently held that “[t]he extent of federal regulation in the area of transportation, loading, unloading and storage of hazardous materials is comprehensive.” Consolidated Rail Corp. v. Bayonne, 724 F.Supp. 320, 330 (D.N.J.1989) (emphasis added). The court *358 noted with approval the DOT’S inconsistency ruling which found that these regulations constitute “a comprehensive series of regulations relating to the storage of hazardous materials incidental to transportation by rail.” Id.

Despite DOT’s extensive regulation of loading, unloading, transfer and storage incidental to the transportation of hazardous materials, the Nevada regulations require a carrier to obtain an annual permit prior to engaging in these activities within the state of Nevada. The Nevada regulations, thus, create a separate regulatory regime for these activities, fostering confusion and frustrating Congress’ goal of developing a uniform, national scheme of regulation. The resulting confusion is exacerbated by the fact that the Nevada regulations only apply to some of the hazardous materials covered by the HMTA and HMR and not to others. Compare 49 CFR §§ 171.8 and 174.14(a) to Nev.Admin.Code § 705.310.

The federal regulations also impose specific information and documentation requirements deemed necessary for the safe transportation of hazardous materials. See e.g., 49 CFR §§ 171.15 and .16. The additional requirements imposed by the Nevada regulations are both redundant (see e.g., Nev.Admin.Code § 705.330(f)) and burdensome {see e.g., Nev.Admin.Code § 705.330(b) (requiring “[a] report identifying each switch, siding, spur or branch of track at the site and its purpose)). Further, they indicate the state’s attempt to regulate areas clearly addressed in the federal regulations. For example, despite the HMR’s detailed requirements with respect to the loading and unloading of hazardous materials, the Nevada regulations require applicants to submit “[a]n outline of the procedure to be used in the loading, unloading, transfer or storage of the hazardous material.” Nev.Admin.Code § 705.330(g). The PSC’s approval of an application is apparently contingent upon its satisfaction with the procedures used.

Similarly, although 49 CFR §§ 174.16 (a), (b) and 174.55(e) require that rail carriers store hazardous materials in a secure facility and §§ 173.3 and 174.8 authorize the DOT to inspect storage sites for compliance, Nev.Admin.Code § 705.330(h) requires applicants to submit an outline of its security measures. Again, the PSC’s approval of an application is apparently contingent upon its satisfaction with the precautions taken. Under the open-ended Nevada regulations, the PSC could conceivably refusé an application based on its dissatisfaction with loading procedures or security measures adopted pursuant to the federal regulations and approved by federal inspectors. Conversely, the PSC could conceivably approve a permit application despite the fact that loading procedures or security measures violate federal regulations.

Finally, the fact that Nev.Admin.Code § 705.370 authorizes the PSC to require an applicant to submit any additional information that it deems necessary may also lead to great expense and delay. In fact, the Nevada regulations confer broad discretion upon the PSC. Rather than establishing measurable standards, the regulations give the PSC the authority to approve or disapprove the procedures followed by a rail carrier. At least one federal court has held similarly vague regulations invalid under the Supremacy Clause, the Commerce Clause and the due process clause of the fourteenth amendment. See Union Pacific Railroad Co. v. City of Las Vegas, CV-S-85-932 HDM (D.Nev., May 12, 1989).

For these reasons, the DOT determined that the Nevada regulations, specifically sections 705.310, .320, .330, .340, .350, .360, and .370, constitute an obstacle to the execution of the HMTA and HMR and are, therefore, inconsistent under the “obstacle test,” the second leg of inconsistency analysis under the HMTA. However, the district court based its holding upon its conclusion that “[cjompliance with the Nevada regulations ... does not in any manner prevent the railroad from complying with the federal regulations.” Thus, the district court determined that the Nevada regulations passed the “dual compliance test,” the first leg of the inconsistency analysis described above. Although the DOT based its inconsistency ruling almost *359 entirely upon its determination that the Nevada regulations failed the obstacle test, the district court not only failed to discuss the DOT’s determination with respect to the obstacle test, it completely failed to acknowledge the existence of this second leg of preemption analysis.

Because the DOT authored the HMR, its determination of what constitutes an obstacle to the accomplishment or execution of those regulations is deserving of substantial deference. See Udall, 380 U.S. at 16 , 85 S.Ct. at 801 . Contrary to the district court’s holding, the DOT’s inconsistency ruling is neither “poorly reasoned” nor “based primarily on speculation.” The district court erred in failing to accord sufficient deference to this ruling. Consequently, we reverse the district court’s order and remand for proceedings consistent with this disposition.

Because we hold that the Nevada regulations are preempted by HMTA and HMR, it is unnecessary for us to address the other arguments made by the appellant.

REVERSED and REMANDED.