CSA Preface This is the first edition of CAN/CSA-ISO/TR 13121, Nanotechnologies - Nanomaterial risk evaluation , which is an adoption without modification of the identically titled ISO (International Organization for Standardization) Technical Report 13121 (first edition, 2011-05-15). The ISO Technical Report was developed by ISO/TC 229. This Standard has been developed in compliance with Standards Council of Canada requirements for National Standards of Canada. It has been published as a National Standard of Canada by CSA Group. Scope This Technical Report describes a process for identifying, evaluating, addressing, making decisions about, and communicating the potential risks of developing and using manufactured nanomaterials, in order to protect the health and safety of the public, consumers, workers and the environment. While the overall product stewardship and risk management process set forth in this Technical Report is not unique to nanomaterials, it supplements recognized approaches by providing, where possible, a focus on information and issues specific to nanotechnologies. It offers guidance on the information needed to make sound risk evaluations and risk management decisions, as well as how to manage in the face of incomplete or uncertain information by using reasonable assumptions and appropriate risk management practices. Further, it includes methods to update assumptions, decisions, and practices as new information becomes available, and on how to communicate information and decisions to stakeholders. This Technical Report suggests methods organizations can use to be transparent and accountable in how they manage nanomaterials. To that end, it describes a process of organizing, documenting, and communicating what information organizations have about nanomaterials. This includes acknowledging where information is incomplete, explaining how information gaps were addressed, and explaining the rationale behind the organization\'s risk management decisions and actions.