Alcoa Corporation participates in environmental assessments and cleanups at several locations. These include currently or previously owned or operated facilities and adjoining properties, and waste sites, including Superfund (Comprehensive Environmental Response, Compensation and Liability Act (CERCLA)) sites.

A liability is recorded for environmental remediation when a cleanup program becomes probable and the costs can be reasonably estimated. As assessments and cleanups proceed, the liability is adjusted based on progress made in determining the extent of remedial actions and related costs. The liability can change substantially due to factors such as, among others, the nature and extent of contamination, changes in remedial requirements, and technology advancements.

Alcoa Corporation’s environmental remediation reserve balance reflects the most probable costs to remediate identified environmental conditions for which costs can be reasonably estimated. The following table details the changes in the carrying value of recorded environmental remediation reserves:

Balance at December 31, 2019	$	335
Liabilities incurred		7
Cash payments		(19	)
Foreign currency translation and other		(1	)
Balance at December 31, 2020		322
Liabilities incurred		8
Cash payments		(14	)
Reversals of previously recorded liabilities		(17	)
Foreign currency translation and other		(2	)
Balance at September 30, 2021	$	297

At September 30, 2021 and December 31, 2020, the current portion of Alcoa Corporation’s environmental remediation reserve balance was $37 and $29, respectively.

The Company incurred liabilities of $4 and $8 in the third quarter and nine-month period of 2021, respectively, primarily related to environmental activities at the Point Comfort site in Texas, closure of the anode plant at the Lake Charles site in Louisiana, and wetlands mitigation at the Longview site in Washington, as well as other increases for ongoing monitoring and maintenance at various sites. These charges are primarily recorded in Cost of goods sold and Restructuring and other charges, net on the accompanying Statement of Consolidated Operations. Payments related to remediation expenses applied against the reserve were $3 and $14 in the third quarter and nine-month period of 2021, respectively. These amounts include mandated expenditures as well as those not required by any regulatory authority or third party. Further, the Company recorded reversals of reserves of $17 during the nine-month period of 2021, respectively, related to:

The Company incurred liabilities of $4 and $6 in the third quarter and nine-month period of 2020, respectively, due to charges related to increases for ongoing monitoring and maintenance and environmental consulting work for a remediation project at the Fusina site in Italy. These charges are primarily recorded in Cost of goods sold on the accompanying Statement of Consolidated Operations. Payments related to remediation expenses applied against the reserve were $5 and $14 in the third quarter and nine-month period of 2020, respectively. These amounts include mandated expenditures as well as those not required by any regulatory authority or third party. The reserve also reflects a decrease of $6 in the nine-month period of 2020, due to the effects of foreign currency translation.

The estimated timing of cash outflows on the environmental remediation reserve at September 30, 2021 is as follows:

2021 (excluding the nine months ended September 30, 2021)	$	6
2022 - 2026		176
Thereafter		115
Total	$	297

Reserve balances at September 30, 2021 and December 31, 2020, associated with significant sites with active remediation underway or for future remediation were $241 and $259, respectively. In management’s judgment, the Company’s reserves are sufficient to satisfy the provisions of the respective action plans. Upon changes in facts or circumstances, a change to the reserve may be required. The Company’s significant sites include:

Poços de Caldas, Brazil—The reserve associated with the 2015 closure of the Alcoa Alumínio S.A. smelter in Poços de Caldas, Brazil, is for remediation of historic spent potlining storage and disposal areas. The final remediation plan is currently under review; such review could require the reserve balance to be adjusted.

Fusina and Portovesme, Italy—Alcoa Corporation’s subsidiary Alcoa Trasformazioni S.r.l. has remediation projects underway for its closed smelter sites at Fusina and Portovesme which have been approved by the Italian Ministry for Ecologic Transition (MET), formerly the Italian Ministry of Environment and Protection of Land and Sea (MOE). Work is ongoing for soil remediation at the Fusina site with expected completion by the end of 2023 and at the Portovesme site with expected completion in the second half of 2021. Additionally, annual payments are made to MET over a 10-year period through 2022 for groundwater emergency containment and natural resource damages at the Fusina site. The final remedial design for the groundwater remediation project at Portovesme was completed in 2020 and is awaiting approval from the MET.

Suriname—The reserve associated with the 2017 closure of the Suralco refinery and bauxite mine is for treatment and disposal of refinery waste and soil remediation. The work began in 2017 and is expected to be completed at the end of 2025.

Hurricane Creek, Arkansas—The reserve associated with the 1990 closure of two mining areas and refineries near Hurricane Creek, Arkansas is for ongoing monitoring and maintenance for water quality surrounding the mine areas and residue disposal areas.

Massena, New York—The reserve associated with the 2015 closure of the Massena East smelter by the Company’s subsidiary, Reynolds Metals Company, is for subsurface soil remediation to be performed after demolition of the structures. Remediation work commenced in 2021 and will take four to eight years to complete.

Point Comfort, Texas—The reserve associated with the 2019 closure of the Point Comfort alumina refinery is for disposal of industrial wastes contained at the site, subsurface remediation, and post-closure monitoring and maintenance. The final remediation plan is currently under review, which may result in a change to the existing reserve.

Sherwin, Texas—In connection with the 2018 settlement of a dispute related to the previously-owned Sherwin alumina refinery, the Company’s subsidiary, Copano Enterprises LLC, accepted responsibility for the final closure of four bauxite residue waste disposal areas (known as the Copano facility). Work commenced on the first residue disposal area in 2018 and will take eight to ten years to complete, depending on the nature of its potential re-use. Work on the next three areas has not commenced but is expected to be completed by 2048, depending on its potential re-use.

Longview, Washington—In connection with a 2018 Consent Decree and Cleanup Action Plan with the State of Washington Department of Ecology, the Company’s subsidiary, Northwest Alloys as landowner, accepted certain responsibilities for future remediation of contaminated soil and sediments at the site located near Longview, Washington. In December 2020, the lessee of the land, who is a partner in the remediation of the site, filed for bankruptcy. As of September 30, 2021, the reserve related to the site is deemed to be sufficient.

Other Sites—The Company is in the process of decommissioning various other plants and remediating sites in several countries for potential redevelopment or to return the land to a natural state. In aggregate, there are approximately 35 remediation projects at these

other sites that are planned or underway. These activities will be completed at various times in the future with the latest expected to be in 2026, after which ongoing monitoring and other activities may be required. At September 30, 2021 and December 31, 2020, the reserve balance associated with these activities was $56 and $63, respectively.

Spain— In July 2013, following a corporate income tax audit covering the 2006 through 2009 tax years, an assessment was received from Spain’s tax authorities disallowing certain interest deductions claimed by ParentCo’s Spanish consolidated tax group. Through various stages of subsequent appeal, denial, and re-assessment through the third quarter of 2018, Alcoa Corporation management came to believe that it was no longer more likely than not (greater than 50%) to prevail in this matter. Accordingly, in the third quarter of 2018, Alcoa Corporation recorded a charge of $30 (€26) in Provision for income taxes to establish a liability for its portion of the estimated loss in this matter, representing management’s best estimate at the time.

On November 8, 2018, Alcoa filed a petition for appeal to the Supreme Court of Spain. During the fourth quarter of 2020, the Supreme Court of Spain met and ruled in favor of Alcoa on the 2006 through 2009 tax year assessment. The ruling is final and cannot be further appealed. As a result of the final ruling, in the fourth quarter of 2020 Alcoa reversed the $32 (€26) reserve that was established in 2018 and the matter is now considered closed. Additionally, a lien secured with the San Ciprián smelter to Spain’s tax authorities that was provided in relation to this matter has been released.

Brazil (AWAB)— In March 2013, AWAB was notified by the Brazilian Federal Revenue Office (RFB) that approximately $110 (R$220) of value added tax credits previously claimed are being disallowed and a penalty of 50% assessed. Of this amount, AWAB received $41 (R$82) in cash in May 2012. The value-added tax credits were claimed by AWAB for both fixed assets and export sales related to the Juruti bauxite mine and São Luís refinery expansion. The RFB has disallowed credits they allege belong to the consortium in which AWAB owns an interest and should not have been claimed by AWAB. Credits have also been disallowed as a result of challenges to apportionment methods used, questions about the use of the credits, and an alleged lack of documented proof. AWAB presented defense of its claim to the RFB on April 8, 2013. If AWAB is successful in this administrative process, the RFB would have no further recourse. If unsuccessful in this process, AWAB has the option to litigate at a judicial level. Separately from AWAB’s administrative appeal, in June 2015, a new tax law was enacted repealing the provisions in the tax code that were the basis for the RFB assessing a 50% penalty in this matter. As such, the estimated range of reasonably possible loss for these matters is $0 to $41 (R$220). It is management’s opinion that the allegations have no basis; however, at this time, the Company is unable to reasonably predict an outcome for this matter.

Australia (AofA)— In December 2019, AofA received a statement of audit position (SOAP) from the Australian Taxation Office (ATO) related to the pricing of certain historic third-party alumina sales. The SOAP proposed adjustments that would result in additional income tax payable by AofA. During 2020, the SOAP was the subject of an independent review process within the ATO. At the conclusion of this process, the ATO determined to continue with the proposed adjustments and issued Notices of Assessment (the Notices) that were received by AofA on July 7, 2020. The Notices asserted claims for income tax payable by AofA of approximately $154 (A$214). The Notices also included claims for compounded interest on the tax amount totaling approximately $509 (A$707).

On September 17, 2020, the ATO issued a position paper with its preliminary view on the imposition of administrative penalties related to the tax assessment issued to AofA. This paper proposed penalties of approximately $92 (A$128). AofA disagrees with the ATO’s proposed position on penalties and submitted a response to the position paper in the fourth quarter of 2020. After the ATO completes its review of AofA’s response, the ATO could issue a penalty assessment.

The Company does not agree with the ATO’s positions, and AofA will continue to defend this matter and pursue all available dispute resolution methods, up to and including the filing of proceedings in the Australian Courts, a process which could last several years and could involve significant expenses. The Company maintains that the sales subject to the ATO’s review, which were ultimately sold to Aluminium Bahrain B.S.C., were the result of arm’s length transactions by AofA over two decades and were made at arm’s length prices consistent with the prices paid by other third-party alumina customers.

In accordance with the ATO’s dispute resolution practices, AofA paid 50% of the assessed income tax amount exclusive of interest and any penalties, or approximately $74 (A$107), during the third quarter 2020, and the ATO is not expected to seek further payment prior to final resolution of the matter. If AofA is ultimately successful, any amounts paid to the ATO as part of the 50% payment would be refunded. AofA funded the payment with cash on hand and recorded the payment within Other noncurrent assets as a tax assessment deposit; the related September 30, 2021 balance is $77 (A$107).

Further interest on the unpaid tax and interest amounts will continue to accrue during the dispute. The initial interest assessment and the additional interest accrued are deductible against taxable income by AofA but would be taxable as income in the year the dispute is resolved if AofA is ultimately successful. AofA applied this deduction beginning in the third quarter of 2020 which reduced cash tax payments by approximately $158 (A$219) in 2020 and $3 (A$4) and $10 (A$14), respectively, in the third quarter and nine-month

period of 2021. This amount has been reflected within Other noncurrent liabilities and deferred credits as a noncurrent accrued tax liability; the related September 30, 2021 balance is $168 (A$233).

The Company continues to believe it is more likely than not that AofA’s tax position will be sustained and therefore is not recognizing any tax expense in relation to this matter. However, because the ultimate resolution of this matter is uncertain at this time, the Company cannot predict the potential loss or range of loss associated with the outcome, which may materially affect its results of operations and financial condition. References to any assessed U.S. dollar amounts presented in connection with this matter have been converted into U.S. dollars from Australian dollars based on the exchange rate in effect as of September 30, 2021.

AofA is part of the Company’s joint venture with Alumina Limited, an Australian public company listed on the Australian Securities Exchange. The Company and Alumina Limited own 60% and 40%, respectively, of the joint venture entities, including AofA.

Spain— During 2019, the Company completed the divestiture of the Avilés and La Coruña (Spain) aluminum facilities to PARTER Capital Group AG (PARTER) in a sale process endorsed by the Spanish government and supported by the workers’ representatives following a collective dismissal process. In connection with the divestiture, Alcoa committed to make financial contributions to the buyer of up to $95; $78 has been paid to date. In 2020, PARTER sold its majority stake in the facilities to an unrelated party. Alcoa had no knowledge of the subsequent transaction prior to its announcement and on August 28, 2020, Alcoa filed a lawsuit with the Court of First Instance in Madrid, Spain asserting that the sale was in breach of the sale agreement between Alcoa and PARTER.

Related to this divestiture, certain claims and investigations have been initiated by or at the request of the employees of the facilities against their current employers, the owners of the current employers, and Alcoa, alleging that the agreements of the collective dismissal process remain in force and that Alcoa remains liable for related social benefits to the employees. One of the claims is a collective case before the Spanish National Court, filed on November 10, 2020, where the workers’ representatives and employees are seeking for the terms of the Collective Dismissal Agreement signed with the workers in January 2019 to be fulfilled or, alternatively, payment of severance corresponding to an unfair dismissal.

On June 15, 2021, the Spanish National Court ruled that the collective dismissal agreement for the divested Avilés and La Coruña aluminum facilities is still in effect and that Alcoa is liable for related employee severance. Alcoa has not recorded a reserve related to the matter, has filed an appeal with the Spanish Supreme Court and will continue to defend this matter and pursue all available legal resolution methods. At this time, Alcoa Corporation is unable to reasonably predict the ultimate outcome or range of loss associated with the outcome of this matter, which may materially affect its results of operations.

Alcoa continues to believe it acted in good faith, in full compliance with the law and with all of the terms that it committed to in the contract for the sale of the Avilés and Coruña facilities to PARTER and in the agreements that it entered into with the representatives of the workers of both facilities.

In addition to the matters discussed above, various other lawsuits, claims, and proceedings have been or may be instituted or asserted against Alcoa Corporation, including those pertaining to environmental, safety and health, commercial, tax, product liability, intellectual property infringement, employment, and employee and retiree benefit matters, and other actions and claims arising out of the normal course of business. While the amounts claimed in these other matters may be substantial, the ultimate liability is not readily determinable because of the considerable uncertainties that exist. Accordingly, it is possible that the Company’s liquidity or results of operations in a particular period could be materially affected by one or more of these other matters. However, based on facts currently available, management believes that the disposition of these other matters that are pending or asserted will not have a material adverse effect, individually or in the aggregate, on the financial position of the Company.