Health - the 2004 OHS Act now specifically states that 'health' includes psychological health. This means that bullying, stress, fatigue, etc are clearly covered by the Act.
Person - includes a body corporate, unincorporated body or association and a partnership - so this means that whenever the Act states 'person' it often is not a human person at all.
Reasonably practicable - this is covered under Part 3, Section 20 of the Act and applies to the general duties relating to health and safety:
"To avoid doubt, for the purposes of this Part and the regulatons, regard must be had to the following matters in determining what is (or was at a particular time) reasonably practicable in relation to ensuring health and safety -
(a) the likelihood of the hazard or risk concerned eventuating;
(b) the degree of harm that would result if the hazard or risk eventuated;
(c) what the person concerned knows, or ought to reasonably know, about the hazard or risk and any ways of eliminating or reducing the hazard or risk;
(d) the availability and suitability of ways to eliminate or reduce the hazard or risk;
(e) the cost of eliminating or reducing the hazard or risk."
This does not mean that if the cost of eliminating or fixing something is very high, then it does not need to be done. What Chris Maxwell said in his review was that if something was capable of being done, then it should be done - and cost was only one aspect that had to be considered.
WorkSafe has produced a guideline (made under Section 12 of the OHS Act, 2004): How WorkSafe applies the law in relation to Reasonably Practicable which explains the concept and its application.
The 2004 Act can be downloaded (in both pdf and Word format) on the Victorian government legislation repository website.