In previous postings, we discussed the employment contract which exists between all employees and their employers. Implied in most verbal employment contracts is a term recognizing that employees who see their employment terminated for grounds other than “just cause”, are entitled to reasonable notice of their termination, or payment in lieu thereof.
But what is “just cause” and what happens to a worker’s right when their employer alleges it? Just cause can be claimed when an employee’s conduct is incompatible with their continued employment. As one classic decision on just cause put it:
If an employee has been guilty of serious misconduct, habitual neglect of duty, incompetence, or conduct incompatible with his duties, or prejudicial to the employer’s business, or if he has been guilty of wilful disobedience to the employer’s workers in a manner of substance, the law recognizes the employer’s right summarily to dismiss the delinquent employee. 
While the Arthur’s case continues to be cited today, the core question in any case where an employer relies on just cause dismissal is whether the employee has engaged in misconduct that is incompatible with the fundamental terms of the employment relationship.
Establishing just cause is a not a simple exercise. The problem is determining at what point the employee’s misconduct has become incompatible with the employment relationship. For example, an employer would not be able to claim just cause for a single incident of an employee showing up late for work. However, if that same employer has made repeated attempts to correct absenteeism, has enacted work place policies communicating expectations and has engaged in repeated coaching with employees chronically late, a case for just cause would likely be more successful.
Essentially, employers must prove two things: that the conduct relied upon for dismissal actually took place and that it was serious enough to warrant a summary dismissal. This can be challenging, as undoubtedly, employees have a very different point of view of the facts of the case, and will not hesitate to tell the court about them.
Allegations of just cause termination are serious matters. It is highly recommended that any employer considering terminating employees for just cause should seek legal advice beforehand. Similarly, any employees who are the subject of a just cause termination should immediately seek legal counsel and become apprised of their legal rights.
 – Port Arthur Ship Building Co. v. Arthur (1967), 62 d.l.r. (2d) 342.