What is the constitutional jurisdiction of an employer that employs employees who would otherwise be subject to provincial jurisdiction?

Decisions about constitutional jurisdiction are guided by whether the work of employees who would otherwise be subject to provincial jurisdiction is a vital, essential or integral part of a core federal undertaking. While not necessarily completely unrelated, this inquiry is distinct from the question of whether an employer is incorporated federally or provincially or whether all or some of its employees have been determined to be subject to either federal or provincial employment or labour legislation. In this regard, the test involves looking for practical or functional integration between the core federal undertaking and the employees in question. The judgment is a functional, practical one and does not turn on technical, legal niceties of the employment relationship. The onus is on the party who seeks to invoke an exception to provincial competence over labour relations: see McElrevy v. BC Corps of Commissionaires, 2004 BCHRT 160 at para. 10.