employers to persons other than their employees in relation to the conduct by the employer of its undertaking;
self-employed persons to other persons in relation to the conduct by the self-employed person of their undertaking;
various parties who in some specified way provide or contribute to various things used in or necessary for the undertaking of work (e.g. the workplace, plant, substances);
employees; and
officers, either by their direct duties or by attributed liability for offences by their corporation, partnership or unincorporated association.