We are subject to significant state, local, and federal governmental regulations, including regulations by the various utility commissions in the states where we serve customers. These regulations significantly influence our operating environment, may affect our ability to recover costs from utility customers, affect our ability to implement our corporate strategy, and cause us to incur substantial compliance and other costs. Changes in regulations, interpretations of regulations, or the imposition of new regulations could also significantly impact us, including requiring us to change our business operations. Many aspects of our operations are regulated and impacted by government regulation, including, but not limited to: the rates we charge our retail electric, natural gas, and steam customers; the authorized rates of return of our utilities; construction and operation of electric generating facilities and electric and natural gas distribution systems, including the ability to recover such costs; decommissioning generating facilities, the ability to recover the related costs, and continuing to recover the return on the net book value of these facilities; wholesale power service practices; electric reliability requirements; participation in the interstate natural gas pipeline capacity market; standards of service; issuance of securities; short-term debt obligations; transactions with affiliates; and billing practices. Failure to comply with any applicable rules or regulations may lead to customer refunds, penalties, and other payments, which could materially and adversely affect our results of operations and financial condition.
The rates, including adjustments determined under riders, we are allowed to charge our customers for retail and wholesale services have the most significant impact on our financial condition, results of operations, and liquidity. Rate regulation provides us an opportunity to recover prudently incurred costs and earn a reasonable rate of return on invested capital. However, our ability to obtain rate adjustments in the future is dependent upon regulatory action, the outcome of which can be influenced by the level of opposition by intervening parties; potential rate impacts; increasing levels of regulatory review; and changes in the political, regulatory, or legislative environments. There is no assurance that our regulators will consider all of our costs to have been prudently incurred. In addition, our rate proceedings may not always result in rates that fully recover our costs or provide for a reasonable ROE. We defer certain costs and revenues as regulatory assets and liabilities for future recovery from or refund to customers, as authorized by our regulators. Future recovery of regulatory assets is not assured and is subject to review and approval by our regulators. If recovery of regulatory assets is not approved or is no longer deemed probable, these costs would be recognized in current period expense and could have a material adverse impact on our results of operations, cash flows, and financial condition.
Changes in the local and national political, regulatory, and economic environment have had, and may in the future have, an adverse effect on regulatory decisions, which could impair the ability of our utility subsidiaries to recover costs historically collected from customers. These decisions, which may come from any level of government, may cause us to cancel or delay current or planned projects, to reduce or delay other planned capital expenditures, or to pay for investments or otherwise incur costs that our utilities may not be able to recover through rates or otherwise. In its November 2023 final rate orders for PGL and NSG, the ICC disallowed certain previously incurred capital costs, which resulted in PGL and NSG recording impairment losses in the fourth quarter of 2023, and caused PGL to pause spending on its SMP. After a limited rehearing, the ICC issued a written order in May 2024 approving additional spending for emergency work related to SMP projects. PGL and NSG have appealed the orders to the Illinois Appellate Court. On February 20, 2025, the ICC issued an order setting expectations for PGL's prospective operations under its SMP. The ICC directed us to focus on replacing all cast and ductile iron pipe that has a diameter under 36 inches by January 1, 2035. The ICC also indicated that failure to comply with this directive could subject us to civil penalties under Illinois statute. As a result of these proceedings and order, the recovery of existing and future investments in capital expenditures and our natural gas infrastructure in Illinois is uncertain and future capital plans may be impacted.
Prior to its expiration in December 2023, the QIP rider provided PGL with recovery of, and a return on, qualifying natural gas infrastructure investments that were placed in service between regulatory rate reviews. Due to the expiration of the QIP rider, PGL included the costs of necessary infrastructure improvements related to the SMP in its rate case, thereby subjecting the recovery of these costs to regulatory lag. In its August 2024 final order on PGL's 2016 annual reconciliation, the ICC disallowed certain capital costs, which resulted in PGL recording a pre-tax charge to income during the third quarter of 2024 related to the disallowance and the previously recognized return on these investments. This rider continues to be subject to an annual reconciliation whereby costs are reviewed for accuracy and prudency. There can be no assurance that all costs incurred under the QIP rider during the open reconciliation years, which include 2017 through 2023, will be deemed recoverable by the ICC. The risk of costs being deemed unrecoverable during the review of the outstanding reconciliations, could have a material adverse impact on PGL's, and correspondingly our, results of operations, financial position, and liquidity.
We believe we have obtained the necessary permits, approvals, authorizations, certificates, and licenses for our existing operations, have complied in all material respects with all of their associated terms, and that our businesses are conducted in accordance with applicable laws. These permits, approvals, authorizations, certificates, and licenses may be revoked or modified by the agencies that granted them if facts develop that differ significantly from the facts assumed when they were issued. In addition, permits and other approvals and licenses are often granted for a term that is less than the expected life of the associated facility. Licenses and permits may require periodic renewal, which may result in additional requirements being imposed by the granting agency. In addition, existing regulations may be revised or reinterpreted by federal, state, and local agencies, or these agencies may adopt new laws and regulations that apply to us. We cannot predict the impact on our business and operating results of any such actions by these agencies.
If we are unable to recover costs of complying with regulations or other associated costs in customer rates in a timely manner, or if we are unable to obtain, renew, or comply with these governmental permits, approvals, authorizations, certificates, or licenses, our results of operations and financial condition could be materially and adversely affected.