The colleague, who has since died, complained to his supervisor that MacDonald had abused him and squirted water from a high-pressure hot water hose into his face.
As result of the allegation, MacDonald was stood down and, after an internal investigation, he was sacked.
MacDonald denied he had deliberately squirted his colleague, and claimed the investigation had been poorly managed. The ERA rejected these claims.
It also rejected MacDonald's submission that the company had failed to interview two witnesses.
The ERA determined that he had deliberately squirted his colleague in the face and that the dismissal was justified.