This educational guide is based on the linked primary sources. It is not a Court publication, is not affiliated with the Court, and is not legal advice.
In brief
Overview
The case concerns whether the discharge of mine‑tailings (fill material) into a lake is regulated as “fill” under Clean Water Act section 404, which would give permitting authority to the Army Corps of Engineers, or as “effluent” under section 402, which would be regulated by the EPA.
The EPA’s definition of “fill” is referenced in the arguments.
Background and question before the Court
The central legal question is whether the discharge of mine tailings constitutes “fill,” which would place permitting authority with the Army Corps of Engineers under CWA §404, or “effluent,” which would be regulated by the EPA under §402.
What each side argues
Petitioners (Coeur Alaska, Inc. and Alaska)
Source-limited. The record does not yet support a complete account.
Respondent (Southeast Alaska Conservation Council)
According to Respondents, expert agencies charged with implementing the Clean Water Act have concluded that the discharge of fill material should be permitted by the Army Corps of Engineers under CWA §404 and is not subject to EPA effluent guidelines under §402.
According to Mr. Waldo (Respondents), according to Mr. Waldo (Respondents), ePA has historically regulated industrial sources whose wastewater contains high levels of suspended solids that effectively act as fill material.
According to Mr. Olson, both a §402 permit and a §404 permit are involved in the case: the §402 permit covers material leaving the lake, while the §404 permit covers material entering the lake.
What happened at oral argument
According to Chief Justice Roberts, chief Justice Roberts announced the hearing of the case.
Chief Justice Roberts asked whether the EPA definition of fill applies to solids.
According to Justice Scalia, justice Scalia questioned whether the Court could have simply vetoed the permit if it found the discharge problematic.
Justice Breyer asked whether the slurry of tailings was covering the lake bottom with dirt and hazardous chemicals.
According to Mr. Olson (Government), according to Mr. Olson (Government), the government argued that if the discharge is classified as fill, the permitting agency is the Army Corps of Engineers.
According to Mr. Olson, the government also noted that both a §402 permit and a §404 permit are present in the case.
- [1] 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdf, p. 4
- [2] 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdf, p. 31
- [3] 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdf, p. 47
- [4] 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdf, p. 48
- [5] 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdf, p. 23
- [6] 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdf, p. 58
What the Court decided
Why it matters
Terms to know
No glossary terms are available for this guide.
Primary sources
Read the source materials on the official site or open the immutable repository copy used for this guide.
- 9818893e1524dc2ff1e0-r1-5fe0ab4dec86271b.pdforal argument transcript
Guide generated September 23, 2026. Automated validation accepted this version.