---
kind: "section"
citation: "33 U.S.C. § 4010"
title: "33"
title_heading: "Navigation and Navigable Waters"
number: "4010"
heading: "Hypoxia or harmful algal bloom of national significance"
release: "119-102"
date: "2026-07-12"
url: "https://uscodex.org/usc/33/4010"
units:
  - "Chapter 53 — Harmful Algal Bloom and Hypoxia Research and Control"
---

# §4010. Hypoxia or harmful algal bloom of national significance

- (1) **Relief—**
  - (A) **In general—** Upon a determination under [paragraph (2)](#2) that there is an event of national significance, the appropriate Federal official is authorized to make sums available to the affected [State](/usc/33/4008.md?p=6) or local government for the purposes of assessing and mitigating the detrimental environmental, economic, subsistence use, and public health effects of the event of national significance.
  - (B) **Federal share—** The Federal share of the cost of any activity carried out under this paragraph for the purposes described in [subparagraph (A)](#1-A) may not exceed 50 percent of the cost of that activity.
  - (C) **Donations—** Notwithstanding any other provision of law, an appropriate Federal official may accept donations of funds, services, facilities, materials, or equipment that the appropriate Federal official considers necessary for the purposes described in [subparagraph (A)](#1-A). Any funds donated to an appropriate Federal official under this paragraph may be expended without further appropriation and without fiscal year limitation.
- (2) **Determinations—**
  - (A) **In general—** At the discretion of an appropriate Federal official, or at the request of the Governor of an affected [State](/usc/33/4008.md?p=6), an appropriate Federal official shall determine whether a [hypoxia](/usc/33/4008.md?p=4) or [harmful algal bloom](/usc/33/4008.md?p=3) event is an event of national significance.
  - (B) **Considerations—** In making a determination under [subparagraph (A)](#2-A), the appropriate Federal official shall consider the toxicity of the [harmful algal bloom](/usc/33/4008.md?p=3), the severity of the [hypoxia](/usc/33/4008.md?p=4), its potential to spread, the economic impact, the relative size in relation to the past 5 occurrences of [harmful algal blooms](/usc/33/4008.md?p=3) or [hypoxia](/usc/33/4008.md?p=4) events that occur on a recurrent or annual basis, and the geographic scope, including the potential to affect several municipalities, to affect more than 1 [State](/usc/33/4008.md?p=6), or to cross an international boundary.
- (3) **Definitions—** In this subsection:
  - (A) **Appropriate federal official—** The term “appropriate Federal official” means—
    - (i) in the case of a marine or coastal [hypoxia](/usc/33/4008.md?p=4) or [harmful algal bloom](/usc/33/4008.md?p=3) event, the [Under Secretary](/usc/33/4008.md?p=8) of Commerce for Oceans and Atmosphere; and
    - (ii) in the case of a freshwater [hypoxia](/usc/33/4008.md?p=4) or [harmful algal bloom](/usc/33/4008.md?p=3) event, the [Administrator](/usc/33/4008.md?p=2) of the Environmental Protection Agency.
  - (B) **Event of national significance—** The term “event of national significance” means a [hypoxia](/usc/33/4008.md?p=4) or [harmful algal bloom](/usc/33/4008.md?p=3) event that has had or will likely have a significant detrimental environmental, economic, subsistence use, or public health impact on an affected [State](/usc/33/4008.md?p=6).
  - (C) **Hypoxia or harmful algal bloom event—** The term “[hypoxia](/usc/33/4008.md?p=4) or [harmful algal bloom](/usc/33/4008.md?p=3) event” means the occurrence of [hypoxia](/usc/33/4008.md?p=4) or a [harmful algal bloom](/usc/33/4008.md?p=3) as a result of a natural, anthropogenic, or undetermined cause.

## Source credit

(Pub. L. 115–423, § 9(g), Jan. 7, 2019, 132 Stat. 5463.)

## Notes

### Editorial Notes

### Codification

This section was enacted as part of the Harmful Algal Bloom and Hypoxia Research and Control Amendments Act of 2017 and also as part of the National Integrated Drought Information System Reauthorization Act of 2018, and not as part of the Harmful Algal Bloom and Hypoxia Research and Control Act of 1998 which comprises this chapter.