Onterris, Inc.

In addition to the Principles of Corporate Governance, the Board of Directors has adopted a Code of Ethics and Business Conduct applicable to employees and a Code of Ethics and Business Conduct applicable to the Board. These Codes of Ethics, along with the Principles of Corporate Governance, serve as the foundation for the Company’s system of corporate governance. They also provide guidance for maintaining ethical behavior, require that directors and employees comply with applicable laws and regulations, prohibit conflicts of interest and provide mechanisms for reporting violations of the Company’s policies and procedures.

In the event the Company makes any amendment to, or grants any waiver from, a provision of the Code of Ethics applying to the principal executive officer, principal financial officer or principal accounting officer that requires disclosure under applicable SEC or NYSE rules, the Company will disclose such amendment or waiver and the reasons therefor on its website atwww.montrose-env.com.