Planning Threat Assessments (TAs) within an area consisting of numerous chemical installations, should be part of adequate and sound Management Of Change procedures (including a baseline periodic TA, on top of change control) of every company belonging to the chemical and process industries. This paper discusses the optimization of threat assessment planning activities. By establishing a planning procedure that objectively determines the need for TAs for all kinds of threats, correct, updated and consistent information becomes easily available to the company's security management department. Threat assessments to be carried out in each facility belonging to an organization can thus easily be scheduled on an organization-wide scale. A prioritization can be made considering legislative requirements, the type of threats, the type of assessment to be carried out, the availability of external experts, etc. (C) 2013 Elsevier Ltd. All rights reserved.