Northgate Village Development v. Orem City, 450 P.3d 1117

Northgate bought former City of Orem public-works property and, while excavating to prepare it for sale, uncovered extensive subsurface debris including asphalt and many other items; cleanup cost ~ $3 million.
Purchase agreement required the City to “complete any environmental clean-up responsibilities specified in the written action plan.” A Clean-Up List attached to the contract identified items including landfill operations for asphalt and buried transformers.
District court initially held the Clean-Up List was the only “written action plan” and interpreted it to require removal only of buried transformers; other material required only permitting to leave in place.
On appeal (Northgate I) the court of appeals found the Clean-Up List ambiguous as to whether the City was required to remove buried asphalt (remanded for fact-finding).
On remand the district court excluded (1) evidence about non-asphalt debris (Fill Material Evidence) as irrelevant/prejudicial and (2) two Northgate experts as a discovery sanction for failing to include certain material in expert disclosures; the court of appeals reversed both exclusions.
Utah Supreme Court granted certiorari and affirmed the court of appeals: district court applied the wrong version of Rule 26 when sanctioning experts and misapplied relevance and Rule 403 balancing in excluding Fill Material Evidence.

Issue	Plaintiff's Argument	Defendant's Argument	Held
Whether district court properly excluded Northgate’s experts as a discovery sanction for failing to disclose “all data and other information”	Northgate: experts did not rely on the challenged study; supplemental declarations showed reliable methodology and satisfied the pre-2011 Rule 26 requirements	City: disclosures were inadequate and experts relied on an unreliable study; sanction warranted under Rule 26 and Rule 37	Court: exclusion was error — district court applied the post‑2011 Rule 26 requirement (“all data”) to a 2009 case governed by pre‑2011 rule; abuse of discretion and harmful error; experts should not have been excluded on that basis
Whether district court properly excluded evidence about non-asphalt landfill material (Fill Material Evidence) as irrelevant and unduly prejudicial	Northgate: debris beyond asphalt is relevant to contractual ambiguity, parties’ intent, damages, and mitigation — not limited to asphalt	City: non-asphalt evidence would confuse jury about scope, unfairly prejudice City, and invite punitive sentiment	Court: exclusion was error — district court misread Northgate I, treated the issue as limited to asphalt, failed to apply proper Rule 401 relevance analysis and did not perform the Rule 403 probative-vs-unfair-prejudice balancing; abuse of discretion

Brown v. Div. of Water Rights of Dep’t of Nat. Res., 228 P.3d 747 (standard for certiorari review of court of appeals decisions)
State v. Griffin, 384 P.3d 186 (distinguishing correctness and abuse‑of‑discretion standards for admissibility decisions)
Schroeder v. Utah Att’y Gen.’s Office, 358 P.3d 1075 (legal error in applying wrong standard can constitute abuse of discretion)
Northgate Vill. Dev., LC v. Orem City, 325 P.3d 123 (Utah Ct. App. 2014) (Northgate I: Clean‑Up List ambiguous; remand for intent regarding asphalt/landfilling entries)
Northgate Vill. Dev., LC v. Orem City, 427 P.3d 391 (Utah Ct. App. 2018) (Northgate II: reversed district court evidentiary exclusions)
Kilpatrick v. Bullough Abatement, Inc., 199 P.3d 957 (abuse of discretion may follow from an erroneous legal conclusion)
Daines v. Vincent, 190 P.3d 1269 (district courts have broad discretion on evidentiary rulings)
Jones v. Layton/Okland, 214 P.3d 859 (abuse‑of‑discretion standard explained)
Maak v. IHC Health Servs., Inc., 372 P.3d 64 (district court abuses discretion when decision rests on an erroneous legal determination)