18.5 The Model Work Health and Safety Act (Model Act) developed by Safe Work Australia, and the Work Health and Safety Bill 2011 (Cth), move away from the use of ‘employer’ to a more inclusive view of the primary duty holder, using the term ‘person conducting a business or undertaking’ (PCBU). However, the term PCBU is not yet used in Commonwealth legislation. Due to the implications of such an expanded definition, and to make the traditional distinction between employers and employees clear, unless referring to the duties under the Model Act, the terms ‘employer’, and occasionally ‘duty holder’ when referring specifically to a duty of care, are used in this chapter.
18.6 Similarly, the terms‘employee’ and ‘worker’ are used interchangeably throughout the chapter. Employee is generally used when discussing the distinction between employees and employers as classes of people, and ‘worker’ for the purposes of the Model Act, recognising that it adopts a broad definition of ‘worker’ instead of ‘employee’, due in part to the changing nature of work relationships.
18.7 This chapter uses the term ‘workplace’ when referring to the place where work is carried out. Under the Model Act and Work Health and Safety Bill, the duty of care is tied to work activities and there is no place of work restriction. Workplace is defined broadly to include any place where work is carried out or where a worker goes, or is likely to be, while at work.
 The principal duty holder under the Model Act is a person conducting a business or undertaking, defined in s 5: Safe Work Australia, Model Work Health and Safety Act, Revised Draft, 23 June 2011.
 Safe Work Australia, Explanatory Memorandum—Model Work Health and Safety Act (2010), . ‘Worker’ is defined as a person who carries out work in any capacity for an employer, including in any of the capacities listed, such as employee, contractor or subcontractor, outworker, apprentice, student or volunteer: Safe Work Australia, Model Work Health and Safety Act, Revised Draft, 23 June 2011 s 7.
 Safe Work Australia, Model Work Health and Safety Act, Revised Draft, 23 June 2011 s 8. Note also there is no requirement for an immediate temporal connection between the place or premises and the work to be performed: Safe Work Australia, Explanatory Memorandum—Model Work Health and Safety Act (2010), –.