## Facts

- The Center for Biological Diversity (CBD) challenged the EPA’s approval of Washington’s and Oregon’s Clean Water Act (CWA) § 303(d) impaired-waters lists for a listing cycle based on data through 2010.
- Ocean acidification results from seawater absorbing atmospheric CO₂ and related chemical reactions that lower ocean pH; near-shore acidity can also be influenced by local and regional inputs (e.g., nutrient runoff, stormwater, industrial pollution, and other emissions).
- Washington and Oregon did not list any coastal or estuarine waters as impaired by ocean acidification, and EPA approved both lists.
- CBD alleged the scientific record showed widespread acidification and harm to shell-forming organisms and that the states and EPA failed to account for “existing and readily available” water-quality data.
- CBD sued under the Administrative Procedure Act (APA), asserting EPA’s approvals were arbitrary and capricious and contrary to the CWA and EPA regulations.
- The parties filed cross-motions for summary judgment on an administrative record; industry amici contested CBD’s Article III standing based on the global nature of atmospheric CO₂.

## Issues

1. Whether CBD had Article III standing to challenge EPA’s approvals, including causation and redressability given that global atmospheric CO₂ is a primary driver of ocean acidification.
2. Whether EPA acted arbitrarily and capriciously in approving Washington’s and Oregon’s § 303(d) lists that did not include coastal or estuarine waters impaired by ocean acidification.
3. Whether EPA unlawfully approved the lists despite an alleged failure by the states to assemble and evaluate all “existing and readily available” water-quality-related data.

## Decision

- The court held CBD had Article III standing because localized sources could contribute to acidification “hot spots,” and relief could lead to listings and follow-on controls addressing local contributors.
- The court denied CBD’s motion for summary judgment and granted EPA’s cross-motion.
- The court held EPA’s approvals were not arbitrary or capricious under the APA.
- The court concluded EPA reasonably determined the states had assembled and evaluated existing and readily available water-quality-related data for the challenged listing cycle.

## Legal Principles

- Article III standing may be satisfied where plaintiffs plausibly allege that local contributors materially affect a localized environmental harm and that the requested relief could reduce that harm, even if a global factor is a primary driver.
- Under APA arbitrary-and-capricious review, a court upholds agency action if the agency considered relevant factors and gave a rational explanation grounded in the record at the time of decision.
- Courts generally defer to an agency’s technical and scientific judgments in implementing CWA § 303(d), particularly where available data and methods do not compel a segment-specific impairment finding under existing state criteria.
- CWA § 303(d) regulations require states to assemble and evaluate all “existing and readily available” water-quality-related data; EPA may approve a list where the record supports a reasonable conclusion that this requirement was met.

## Conclusion

The court found CBD had standing to challenge EPA’s approvals based on alleged local contributions to ocean acidification, but upheld EPA’s approval of Washington’s and Oregon’s impaired-waters lists because, on the administrative record for the relevant cycle, EPA reasonably concluded the available information did not require ocean-acidification listings and that the states had evaluated existing and readily available data.


Ctr. for Biological Diversity v. U.S. Env’t Prot. Agency, 90 F. Supp. 3d 1177 (W.D. Wash. 2015)