---
kind: "section"
citation: "50 C.F.R. § 217.167"
title: "50"
number: "217.167"
heading: "Modifications of letters of authorization."
url: "https://uscodex.org/cfr/50/217.167"
---

# §217.167. Modifications of letters of authorization.

- (a) An LOA issued under [§§ 216.106](/cfr/50/216.106.md) of this chapter and 217.166 for the specified activities may be modified upon request by Hilcorp, provided that:
  - (1) The changes to the activity or the mitigation, monitoring, or reporting does not change the findings made pursuant to this subpart and do not result in more than a minor change in the total estimated number of takes (or distribution by species or stock or years); and
  - (2) NMFS determines that Hilcorp implemented the mitigation, monitoring, and reporting measures required by the LOA for which modification is requested.
- (b) An LOA issued under [§§ 216.106](/cfr/50/216.106.md) of this chapter and 217.166 may be modified at NMFS' initiation if:
  - (1) Doing so creates a reasonable likelihood of more effectively accomplishing the goals of the mitigation and monitoring measures; or
  - (2) NMFS determines that an emergency exists that poses a significant risk to the well-being of the species or stocks of marine mammals specified in an LOA issued pursuant to [§§ 216.106](/cfr/50/216.106.md) of this chapter and 217.166, in which case, the LOA may be modified without prior notice or opportunity for public comment; however, notification will be published in the Federal Register within 30 days of the action.
- (c) If the modifications to the specified activities, mitigation, monitoring, or reporting measures are substantial, NMFS shall publish a notice of proposed LOA in the Federal Register and solicit public comment prior to making a determination on issuance.
- (d) Possible sources of data that could contribute to a decision to modify the LOA include, but are not limited to:
  - (1) Results from Hilcorp's monitoring;
  - (2) Results from other marine mammal and/or sound research or studies; and
  - (3) Any information that reveals marine mammals may have been taken in a manner, extent or number not authorized by this subpart or subsequent LOAs.

## Notes

### Source

Source: 91 FR 8141, Feb. 20, 2026, unless otherwise noted.

### Authority

Authority: 16 U.S.C. 1361 et seq., unless otherwise noted.

### Source

Source: 74 FR 35143, July 20, 2009, unless otherwise noted.