Here is the opinion in El Paso Natural Gas Co. v. United States.

Excerpts:

This case concerns two sites on Navajo tribal lands that the Navajo Nation alleges were contaminated by World War II and Cold War era uranium mining. Pursuant to the Uranium Mill Tailings Remediation and Control Act (UMTRCA), which created a mechanism to cleanup after such activities,  the Navajo Nation asked the Department of Energy to remediate both sites. The department refused, and the district court declined to review that decision, relying on a provision of UMTRCA stating that “designations made, and priorities established, by the Secretary under this section shall be final and not subject to judicial review.” For the reasons set forth in this opinion, we affirm.

And:

Finally, we address two concerns raised at oral argument by counsel for the Navajo Nation. First, he urged us to employ the canon of statutory  interpretation directing courts to liberally construe statutes in favor of Native Americans.Recording of Oral Arg. at 15:48–16:10; Montana v. Blackfeet Tribe of Indians, 471 U.S. 759, 766 (1985). This canon, however, has force only where a statute is ambiguous,  id.;Muscogee (Creek) Nation v. Hodel, 851 F.2d 1439, 1444–45(D.C. Cir. 1988), and as we have explained, section 7912(d), read in light of UMTRCA’s other provisions, is unambiguous.In addition, even were section 7912(d) ambiguous, the presumption applies only to statutes “passed for the benefit of dependent Indian tribes.” Alaska Pac. Fisheries Co. v. United States, 248 U.S. 78, 89 (1918) (interpreting the scope of land included in a reservation created by congressional act); see also San Manuel Indian Bingo & Casino v. NLRB, 475 F.3d 1306, 1312 (D.C. Cir. 2007) (noting that “[w]e have found no case in which the Supreme Court applied this principle of pro-Indian construction when resolving the ambiguity in a statute of general application.”). Here, UMTRCA’s statement of purpose reveals that Congress passed the statute to protect public health in general rather than tribal health in particular.See  § 7901(b) (“The purposes of this chapter are to . . . minimize or eliminate radiation health hazards to the public[.]”).