Sotera Health Co

1. These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 13,708 Restricted Stock Units ("RSUs") granted to the Reporting Person on March 4, 2024. This award was granted pursuant to the terms of an RSU agreement under the Sotera Health Company 2020 Omnibus Incentive Plan ("2020 Incentive Plan"). Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

2. A portion of the Reporting Person's March 3, 2025 additional performance-based RSUs vested on March 2, 2026 based upon the achievement of performance conditions. As a result, the Reporting Person received an additional 17,937 shares of Common Stock.

3. These securities consist of additional performance-based RSUs that were granted on March 3, 2025, pursuant to the terms of an RSU Agreement under the 2020 Incentive Plan. Each additional RSU represented the Reporting Person's right to receive one share of Common Stock subject to stock price-related performance conditions. Regarding the additional RSUs, the Reporting Person vested in 17,937 shares of Common Stock on March 2, 2026. The remaining additional RSUs under the award vest annually in equal installments in March 2027 and March 2028, subject to performance.

4. These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 53,811 RSUs granted to the Reporting Person on March 3, 2025. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to recieve one share of Common Stock, subject to vesting conditions or performance, as applicable.

5. These securities represent the number of shares of Common Stock withheld by the Issuer to satisfy the Reporting Person's tax withholding obligations due upon the vesting of 18,684 RSUs granted to the Reporting Person on March 3, 2025. This award was granted pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions.

6. These securities consist of RSUs that were granted on March 2, 2026, pursuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each RSU represents the Reporting Person's right to receive one share of Common Stock, subject to vesting conditions. The RSUs generally vest annually in 60%, 20%, and 20% installments, respectively, commencing March 2027.

7. These securites consist of the maximum number of additional performance-based RSUs that were granted on March 2, 2026, prusuant to the terms of an RSU agreement under the 2020 Incentive Plan. Each additional RSU represents the Reporting Person's right to receive one share of Common Stock, subject to stock price-related conditions. The additional RSUs generally vest annually in 60%, 20% and 20% installments, respectfully, commencing March 2027, subject to performance.