## Facts

- A CTS subsidiary operated an electroplating facility in Asheville, North Carolina (1959–1986), using trichloroethylene (TCE) and releasing it through sewers, facility drains, and on-site storage.
- CTS ceased operations in 1986 and sold the property in 1987.
- State and federal agencies later found elevated TCE in nearby soil, and by the late 1990s detected high TCE levels in area groundwater and springs.
- In 2008, testing of private drinking-water wells in a nearby residential area (the Oaks Subdivision) found TCE contamination in several wells.
- An EPA contractor’s 2010 investigation suggested the Oaks wells were probably affected by local sources, but not by leaking septic tanks.
- EPA conducted further testing and source evaluation, then applied CERCLA’s Hazard Ranking System (HRS) and scored the site 48.64, relying substantially on a determination that TCE from the CTS property migrated to the Oaks wells.
- EPA issued a final rule adding the site to CERCLA’s National Priorities List (NPL), and CTS petitioned for review, alleging the listing was arbitrary and capricious.

## Issues

1. Whether CTS had Article III standing to challenge EPA’s NPL listing.
2. Whether EPA’s NPL listing decision was arbitrary and capricious under the APA, including EPA’s finding of a hydraulic connection between the site and contaminated residential wells and its treatment of alternative sources.
3. Whether CTS could rely on extra-record scientific evidence developed after the rulemaking to attack the NPL listing.

## Decision

- The court held CTS had Article III standing because NPL listing can impose concrete reputational, regulatory, and financial harms traceable to the listing and redressable by vacatur.
- The court denied the petition for review and upheld EPA’s final rule listing the site on the NPL.
- The court concluded EPA reasonably found a hydraulic connection between the CTS property and the Oaks Subdivision wells and sufficiently evaluated competing explanations for contamination for HRS scoring purposes.
- The court refused to consider CTS’s extra-record evidence (including later-developed isotope analysis) because APA review of rulemaking is generally limited to the administrative record.

## Legal Principles

- Article III standing may be satisfied where a regulated entity shows concrete reputational and economic consequences stemming from an agency listing decision.
- Under APA arbitrary-and-capricious review, a court asks whether the agency examined relevant data and provided a rational explanation connecting the record to its decision; technical scientific judgments receive substantial deference.
- CERCLA NPL listing is a screening and prioritization action rather than a final adjudication of liability, supporting deferential review of EPA’s risk-based HRS determinations at the listing stage.
- In direct APA review of rulemaking, judicial review is confined to the administrative record; parties generally may not introduce later-developed evidence to undermine the agency’s decision.

## Conclusion

The D.C. Circuit upheld EPA’s decision to list the CTS site on the NPL, finding CTS had standing, EPA’s HRS-based determination of contamination pathways was reasonable and adequately explained, and the challenge could not be expanded with extra-record scientific materials developed after the agency’s final action.


CTS Corp. v. EPA, 759 F.3d 52 (D.C. Cir. 2014)