The Ontario Labour Relations Board (“OLRB”) has broad remedial powers under the Labour Relations Act, 1995 (“LRA”) to deal with a range of labour relations issues. That said, section 109(1) of the LRA also gives an applicant the ability to seek the consent of the OLRB to prosecute a respondent criminally.
Initiating a criminal prosecution, not surprisingly, should and is exceptional and the consent of the OLRB should not be easily secured. An early case is A.A.S. Telecommunications Ltd.,  OLRB Rep. Dec. 751 where the OLRB stated:
Speaking more generally, it is clear to us that, given the expanded remedial power of the Board, applicants seeking consent to prosecute must bear a heavy onus to establish that a criminal prosecution is consistent with the promotion of good industrial relations in this province. The remedial powers of this Board have been specifically designed to deal with industrial relations problems. Since full remedial relief from the Board is now available to unions and employers, as well as individual employees, an applicant seeking consent to prosecute should establish why the matter cannot be dealt with effectively by recourse to the Board’s remedies alone. This is not to say that consent to prosecute will never be granted, since there may very well be cases where conduct is so flagrant that only criminal sanction will be the proper deterrent. Nevertheless, before granting consent to prosecute, the Board must be satisfied that the conduct in question cannot be adequately remedied without recourse to the criminal courts. [Emphasis added]
The OLRB put it this way in Fleck Manufacturing Co.,  OLRB Rep. July 615:
On an application for consent to prosecute the function of the Board is to determine whether the evidence discloses a prima facie case against the respondents, raising arguable points of law appropriate for consideration by the Provincial Court. In performing this function the Board must be convinced not only that there is some evidence to support the prosecution but also that a prosecution would serve the interests of the bargaining relationship between the parties or generally advance the interests of collective bargaining in the Province.
The Board will, therefore, first review the evidence to find whether a prima facie case has been made out against each respondent and will turn lastly to consider, if such a case is established, whether it would serve the interests of industrial relations to grant consent to prosecute. It should be emphasized that in reviewing the evidence the Board does not make any final findings of fact nor does it make any ultimate determination as against any of the respondents. That is the exclusive function of the Court.
The principles were applied most recently in McLaughlin v Bluewater District School Board, 2018 CanLII 45193 where the OLRB dismissed an application for consent to institute prosecution for an offence under the LRA. They reaffirmed and applied the above principles and concluded that the issuance of consent to prosecute was intended to be an extraordinary remedy. The OLRB also held that a prosecution, in that case, does not serve the interests of the bargaining relationship between the employer and the union. Finally, there was nothing in the applicant’s allegations or submissions that suggested that collective bargaining in Ontario would be advanced by allowing a prosecution in this case to occur.
As we’d expect, these are rare and uncommon cases.