South Colton Families First, et al, v. City of Colton, et al

Petitioners contended that the Guidelines section 15183 exemption did not apply to the Project because of issues related to the Project’s greenhouse gas emissions, air quality impacts, and historic resources not being protected. Petitioners also asserted that the City’s parking variance violated state planning and zoning laws and Colton’s Municipal Code. As such, on July 21, 2023, Petitioners filed a Petition for a Writ of Mandate against the Respondent City and Real Parties in Interest, alleging (1) violation of CEQA; (2) violation of Planning and Zoning Law; and (3) violation of the City’s municipal code.

Relevant here, on June 3, 2024, the Court issued its ruling and issued a peremptory writ of mandate, granting the Petition in part on November 19, 2025:The Court denied the petition as it related to the greenhouse emissions arguments and as it related to historic resources impacts. However, the Court granted the Petition as it related to operational air quality impacts finding the Guidelines section 15183 exemption was not demonstrated to apply to significant operational air quality impacts due to the City’s failure to engage in mitigation analysis required under section 15183. The Court also granted the Petition as it related to the parking variance: The factors and evidence the City considered were found to be insufficient to meet the requirements for a variance under Government Code section 65906. The finding of special circumstances for purposes of Government Code section 65906 was also found not to be supported by substantial evidence.

Subsequently, on February 20, 2026, Respondents filed the instant joint motion to Discharge Peremptory Writ of Mandate. Petitioners objected and, on March 10, 2026, filed a Motion for Leave to File Supplemental Petition for Writ of Mandate. Both motions are opposed.

Summary of the Law A peremptory writ of mandate in a CEQA proceeding should order the agency to file a return by a date certain informing the court of the agency’s actions in compliance with the writ. Public Resources Code section 21168.9, subdivision (b) states, in relevant part, “The trial court shall retain jurisdiction over the public agency’s proceedings by way of a return to the peremptory writ until the court has determined that the public agency has complied with this division.” This statutory provision for the retention of jurisdiction reflects the rule that a court issuing a peremptory writ of mandate retains jurisdiction to determine the adequacy of the return and ensure full compliance with the writ.” (Ballona Wetlands Land Trust v. City of Los Angeles (2011) 201 Cal.App.4th 455, 479, citations omitted.)

“[T]he trial court’s retained jurisdiction under Public Resources Code section 21168.9, subdivision (b) is limited to ensuring compliance with the peremptory writ of mandate. After considering the petitioner’s challenges to an EIR or other agency action and rendering a final judgment and peremptory writ of mandate, a trial court evaluating a return to the writ may not consider any newly asserted challenges arising from the same material facts in existence at the time of the judgment. To do so would undermine the finality of the judgment.” (Id. at p. 480.) “Case law has repeatedly applied the language of section 21168.9, subdivision (b), to confer continuing jurisdiction on the trial court to enforce the writ until the writ is satisfied.” (McCann v. City of San Diego (2023) 94 Cal.App.5th 284, 295.)

Analysis

Motion for Leave to File Supplemental Petition for Writ of Mandate: Here, Petitioners seek leave to file a supplemental petition in order to challenge the City’s Updated Project that was approved on February 3, 2026, in response to the peremptory writ issued by the Court. Petitioners argue that this Court maintains jurisdiction over the matter because it has not yet discharged the Writ. They claim that the Court of Appeal has addressed this exact procedural situation in City of Carmel-By-The-Sea (1982) 137 Cal.App.3d 964, 971 [“Where, as here, the writ remands the matter to the administrative body with directions to proceed in a certain manner, and the return states that the court’s mandate has been carried out, the petitioner may challenge the validity . . . by supplemental petition (using the original action number).”].)

Respondents argue a supplemental petition is improper for two reasons: First, they argue that to the extent the proposed Supplemental Petition challenges the Project’s operational air quality impacts, the only permissible procedure is to challenge the City’s compliance with the Writ by objecting to the City’s Return to Writ and opposing the motion to discharge the writ (which Petitioners have done). Second, to the extent the proposed Supplemental Petition challenges the City’s approvals for the Project on other grounds, those claims are barred by the doctrine of claim preclusion because they were litigated or could have been litigated previously.

Importantly, here, the November 19, 2025 Peremptory Writ of Mandate stated: “The Court shall retain jurisdiction over the proceedings pursuant to Public Resources Code section 21168.9, subdivision (b) by way of the Return to the Writ of Mandate and any other motions which do not concern appellate review, until the City files a return to writ confirming that the City has taken the steps set forth in paragraphs 1-5, which the City shall file no later than 90 days after the date of the issuance of the Writ confirming that the City has taken the steps set forth in paragraphs 1-5.” (See Peremptory Writ of Mandate, issued November 19, 2025, ¶6.)

In Bair v. California Department of Transportation (2026) 119 Cal.App.5th 579, the Carmel-By- The-Sea case was likewise cited as permitting a petitioner to both object to the return to writ and file a new petition.There, the court rejected the proposition. Instead, the Bair court found: “City of Carmel-by-the-Sea, a non-CEQA case, holds merely that a trial court may adjudicate the adequacy of an agency’s return to a writ of administrative mandate in the original writ proceeding, and that a new writ proceeding need not be initiated for that purpose.” (Bair v. California Department of Transportation (2026) 119 Cal.App.5th 579, 598-599.) In dictum, it also explains that filing a new writ proceeding to challenge compliance with the writ would be proper, but it does not say that both options can be pursued simultaneously. (Ibid.)

Also, as noted by Respondents, the leading treatise on CEQA concurs: “Because Pub[lic] Res[ources] C[ode] § 21168.9(b) requires that the trial court retain jurisdiction over the agency’s proceedings until it finds the agency has complied with the terms of the writ, filing a new or supplemental petition to challenge the return in a CEQA case should not be appropriate.” In the authors’ view, the dictum in City of Carmel-by-the-Sea (a non-CEQA case) that the petitioner in a mandamus proceeding may challenge a return by filing a new or supplemental petition is inapplicable in CEQA cases given the requirements of § 21168.9(b).

(Kostka & Zischke, Practice Under the California Environmental Quality Act (2d ed. 2026) § 23.125A; see, e.g., Joshua Tree Downtown Business Alliance v. County of San Bernardino (2016) 1 Cal.App.5th 677, 695 [recognizing this source as “the leading CEQA treatise”].)

Motion to Discharge Peremptory Writ of Mandate: Notably, the peremptory writ of mandate directed the City to (1) void, vacate, and set aside its Project Approvals set forth in Resolution Nos. R-60-23 and R-73-23 and the variance granted pursuant to Resolution No. R-60- 23; (2) conduct a mitigation analysis for operational air quality impacts pursuant to the ruling and CEQA Guidelines section 15183 prior to the City Council issuing any approvals related to Resolution Nos. R-60-23 and R-73-23; and (3) make findings of special circumstances supported by substantial evidence pursuant to Government Code section 65906 before the City Council takes any action when granting a parking variance related to Resolution No. R-60-23.

Respondents move to discharge the Peremptory Writ of Mandate issued by the Court on November 19, 2025. Respondents argue the City took corrective action to address the identified deficiencies, which included (1) adopting Resolution No. R-04-26 to vacate the original Project resolutions and approvals, including variance [see RJN, Exh. B, Adoption of Resolution No. R-04- 26] and (2) by preparing a revised Initial Study and Consistency Checklist pursuant to Public Resources Code section 21083.3 and CEQA Guidelines section 15183 that evaluate the operational air quality mitigation considerations identified by the Court. (See RJN, Exh. C-I, Adoption of Resolution Nos. R-10-26, R-11-26, R-12-26, and R-13-26.) The City Council subsequently approved the modified Project (Updated Project) on February 3, 2026, based on the updated 15183 Analysis and supporting findings. Respondents maintain that, as reflected in the Return to Writ, the City has satisfied the terms of the Writ by setting aside the original Project and approving this Update Project.

Respondents are correct that the Court identified a single, narrow deficiency as to mitigation analysis pertaining to operational air quality impacts. Though the Court generally upheld the reliance on Guidelines section 15183, the Court determined that the analysis previously did not address project-level mitigation analysis for significant operational air quality impacts as contemplated under the GPEIR despite the City’s Consistency Checklist acknowledging operational nitrogen oxide (NOx) as a Project-specific impact and that air quality impacts remained significant and unavoidable. To address this, the City prepared the Updated 15183 Analysis, which maintains that the Updated Project’s operational NOx emissions would remain significant and unavoidable and concludes that the level of emissions generated would still be less than that assumed for the Project site under the GPEIR. (See RJN, Exh. I-Final Initial Study/Consistency Checklist Agua Mansa Logistics Center Project dated January 16, 2026, at pp. 77-80.)

Consistent with the ruling, the Updated 15183 Analysis identifies, evaluates, and implements feasible mitigation measures for operational air quality impacts and existing regulatory standards for the development of warehouse projects in light of the GPEIR’s mandate for project-level mitigation. (See RJN, Exh. I at pp. 61-80.) Based on all relevant evidence, findings, and proposals therein, the Updated 15183 Analysis, per the Respondents: determines that the proposed mitigation measures from the GPEIR and uniformly applied development policies or standards previously adopted by the City will independently and cumulatively mitigate air quality impacts associated with the Updated Project, particularly as it relates to operational and mobile emission impacts; finds that the Updated Project is consistent with the development density and zoning evaluated in the GPEIR and City’s General Plan; affirms that there is no evidence identifying new significant effects or increases in the severity of previously identified air quality impacts as compared to what was already identified and disclosed in the GPEIR; and maintains that additional environmental analysis is not required for the Updated Project based on the findings of the Updated 15183 Analysis. (RJN, Exh. I at pp. 79-80.)

Here, the operational air quality impacts were evaluated in the Updated Analysis in accordance with CEQA Guidelines 15183. (RJN, Exh. I. at pp. 77-80.) The analysis demonstrates that the Updated Project would result in cumulatively considerable significant impacts persisting over the life of the Project, although the Updated Project’s operational emissions of NOx would exceed the SCAQMD regional threshold and be cumulatively considerable, the Updated Project will result in fewer NOx emissions as compared to the range of land uses for the site as evaluated by the GPEIR. (Id. at p. 77.) Nevertheless, to substantially mitigate significant operational air quality impacts, the Updated Project incorporates a combination of project design features, conditions of approval, and Good Neighbor Policies consistent with General Plan Policies, CEQA requirements, and SCAQMD regulations. (Id. at pp 77-79.) These designs are incorporated into the Updated Project as approved and includes Good Neighbor Policies that are codified in the City’s Municipal Code—thus, constituting mandatory, binding requirements. (See RJN, Exh. M.) Following this completion of the corrective environmental review, the City Council considered and approved the Updated Project at a duly noticed hearing on February 3, 2026. (See RJN, Exhs. C-H.) Finally, the City eliminated the Parking Variance identified by the Court. (See RJN, Exh. B.) Thus, it is also clear this approval fully resolves the Writ directive in this respect.

As a preliminary matter, the Court previously identified the issues upon which the Writ Petition was granted, Respondents have filed a Return, which the Court is tasked with evaluating to determine if the Writ was obeyed. None of the caselaw cited by Petitioners suggests otherwise. Petitioners incorrectly attempt to expand the scope of the instant proceedings. Petitioners argue that the instant motion can consider compliance with CEQA generally. It appears Petitioners are treating the instant motion as an entirely new set of briefs for which they raise many claims beyond the scope of the Court’s ruling. Petitioners mistakenly rely on Natural Resources Defense Council, Inc. v. City of Los Angeles (2023) 98 Cal.App.5th 1176. This Court, however, already made its orders with respect to the Writ, and the Natural Resources Defense Council case does not represent expanding the scope on a Return to Writ. Thus, the Court declines to expand the scope of the instant motion.

Petitioners do discuss, however, the Updated Analysis and argue that it required the implementation of project design features for mitigation but includes only limited discussion of enforcement and is therefore insufficient. The Peremptory Writ required Respondents to conduct a mitigation analysis for operational air quality impacts pursuant to Guidelines section 15183. Whether Respondents did this, Petitioners may challenge herein.

With respect to the mitigation analysis, Petitioners argue that the Updated Analysis fails due to its finding that the Updated Project will have less operational air quality impacts than contemplated by the GPEIR. Although Petitioners did not develop their argument with respect to the Rule 403 (as to how it interacts with CEQA)1, a review of the Updated Analysis shows that with respect to Rule 403, the City complies if it complies with Best Management Practices (BMP) that would implement dust suppression techniques to prevent fugitive dust. But, Petitioners claim that alleging the existence of BMP is insufficient. (See RJN, Exh. I at p. 116.) Petitioners argue that there is, essentially, no guarantee the BMP would be enforced. Petitioners also argue the Good Neighbor policies are voluntary. (See RJN, Exh. I at p. 129.) In other words, Petitioners acknowledge Respondents have addressed the mitigation issues identified in the Writ but claim the response is insufficient because the City’s mitigation lacks an enforcement mechanism. However, the Updated Analysis provides, and Respondents detail in their Reply, that the Updated Project is required to comply with all minimum requirements to reduce man-made fugitive dust as described in Chapter 15.84 of the City’s Municipal Code, and, thus, the practices and policies are mandatory and enforced. (See RJN, Exh. M.)2

The Updated Project also includes the Good Neighbor Policies (GNP) contained within Colton Municipal Code section 18.48.134(j). The updated analysis details GNPs 1, 2, 3, and 7. (See RJN, Exh. I at p. 130.)

In sum, it appears that Petitioners fail to show how the mitigation measures identified are insufficient where the City’s Municipal Code enforces them.

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1 Petitioners merely claim it “bumps up against SCAQMD.” (See Opp, p. 12:24.)

2 BMP are discussed in detail. (See RJN, Exh. I, at p. 116.)