The IIAR Critical Task Guidance for Ammonia Refrigeration System Emergency Planning, 2^nd Edition was published to assist employers, government regulators, and public safety emergency responders in preparing emergency procedures to prepare for ammonia release incidents. The guideline was developed to increase safety when working in and around ammonia refrigeration systems and to mitigate the consequences of accidental releases. It provides guidance for ensuring that new or existing emergency action and/or response plans include appropriate personal protective equipment selection, training, emergency planning, and communication associated with these critical tasks. The guideline was written to especially aid emergency action only facilities in preparing emergency action plans but is also useful for preparing emergency response plans. The 2^nd edition improves upon the 1^st edition with new document organization, additional information, resources, and references.