NEWMARKET CORP

Evaluation of Disclosure Controls and Procedures

We maintain a system of internal control over financial reporting to provide reasonable, but not absolute, assurance of the reliability of the financial records and the protection of assets. Under Rule 13a-15(b) of the Securities Exchange Act of 1934 (the Exchange Act), we carried out an evaluation, with the participation of our management, including our principal executive officer and our principal financial officer, of the effectiveness of our disclosure controls and procedures, as such term is defined in Rule 13a-15(e) of the Exchange Act, as of the end of the period covered by this report. Based upon that evaluation, our principal executive officer and our principal financial officer concluded that our disclosure controls and procedures were effective at the reasonable assurance level. As permitted by SEC guidance, the scope of this evaluation did not include the disclosure controls and procedures of AMPAC related to our internal controls over financial reporting. See Note 2 for further information on this acquisition.

Other than the changes arising from the ongoing integration activities associated with the AMPAC acquisition, there has been no change in our internal control over financial reporting, as such term is defined in Rule 13a-15(f) of the Exchange Act, which occurred during the quarter ended March 31, 2024 that has materially affected, or is reasonably likely to materially affect, our internal control over financial reporting.