At the Employment Relations Authority (ERA), member of the authority Peter van Keulen found Envirowaste did not investigate any of the matters McLeod raised as an explanation for the positive drug test.
"It could quite easily have spoken to Mr McLeod's wife or other family members who were at the party to determine if he was really so intoxicated he might have memory loss of that evening or whether they saw him smoke cannabis."
Van Keulen said throughout the disciplinary process Envirowaste had blurred two allegations, that McLeod attended work under the influence of drugs and that McLeod failed a drug test.
Envirowaste's decision to dismiss McLeod was based on the conclusion that he had been under the influence of drugs at work, a conclusion that was never put to McLeod in a way he could respond to, Van Keulen said.
There were "a myriad of reasons" as to why Envirowaste's decision to dismiss McLeod was unjustified, he said.
"In short, Envirowaste acted in an inherently unfair manner in dismissing Mr McLeod."
The company could have exercised discretion and offered McLeod rehabilitation, which may have meant he could keep his job, Van Keulen said.
Since McLeod was dismissed from his job he had become withdrawn, embarrassed and concerned about what people thought of him losing his job. He had accepted a job that paid significantly less than his previous position with Envirowaste, which led to him being in a position where he had to borrow money from his children.
He awarded McLeod be reimbursed $21,306 in lost wages and $11,000 in compensation for his hurt and humiliation.
Read the full decision here: