Item 5. OTHER INFORMATION

Union Matters

Approximately, 1,100 APS employees are union employees represented by the International Brotherhood of Electrical Workers (“IBEW”). The collective bargaining agreement expired on April 1, 2023, and APS and IBEW have engaged the services of a federal mediator to help facilitate ongoing negotiations. APS and IBEW remain committed to continue bargaining in good faith, and the current contract remains in full force and effect while negotiations continue.

Environmental Matters

EPA Revised Effluent Limitation Guideline Proposal. With respect to the management of bottom-ash transport wastewater at Four Corners, on March 8, 2023 EPA issued a revised proposal for effluent limitation guidelines governing power plant wastewater. For discharges of bottom-ash transport wastewater, EPA has proposed a more stringent “zero-liquid discharge” standard. We cannot at this time predict the outcome of this regulatory proceeding or when the EPA will take final action on this proposal. Depending on the eventual outcome, the costs associated with APS’s management of bottom-ash transport wastewater could materially increase, which could affect APS’s financial position, results of operations, or cash flows.

Revised Mercury and Air Toxics Standard (“MATS”) Proposal. On April 5, 2023, EPA proposed revisions to the existing MATS regulations governing emissions of toxic air pollution from existing coal-fired power plants. If finalized, the proposal would make the limits used to demonstrate compliance with MATS, filterable particulate matter, significantly more stringent (potentially by an order of magnitude) and require the use of continuous emissions monitoring systems to ensure compliance (as opposed to periodic performance testing). Regulations would take effect for existing coal-fired power plants within three years of the proposal becoming final. We cannot at this time predict the outcome of this regulatory proceeding or when the EPA will take final action on this proposal. Depending on the eventual outcome, the costs associated with APS’s

controls for filterable particulate matter could materially increase, which could affect APS’s financial position, results of operations, and cash flows.