He came to work as normal but was called into a meeting with Mr Carroll and a company director and shareholder, Bruce Porter, who told him: "You are correct, you failed your test. The upside is that you are now sacked."
Mr Carroll said what was meant by this was that being sacked was the worst case scenario, and they intended to talk through other options before this step was taken.
"However, before I could go into any detail, [Mr Rusling] became upset and threw what I would call a tantrum," Mr Carroll said.
Mr Rusling told them "I'll see you in court and then "stormed out" of the office, he said.
Mr Carroll and Mr Porter said if Mr Rusling had not left the office in this manner they would not have sacked him immediately.
Authority member Kenneth Anderson did not accept this because Mr Rusling had been told that "the upside" was that he did not have a job.
"While one can only ponder what the possible downside for Mr Rusling could have been, I have little hesitation in finding that Mr Rusling was dismissed at the meeting on 11th June 2010, despite the attempts of Mr Carroll and Mr Porter to suggest otherwise.
"Mr Rusling clearly understood that he had been dismissed and I find that his understanding was well founded, given what was said to him."
The employer was entitled to implement a disciplinary action after the failed test, however, Mr Rusling should have been given the opportunity to explain himself, Mr Anderson said.
Mr Rusling had sought to be reimbursed for three months' lost wages - more than $17,000 - but he had told the authority that three or four weeks after his dismissal he had decided that he would stay home with his daughter, who was experiencing health problems, rather than looking for a new job.
This meant that he could only be compensated for a maximum of four weeks' lost wages and was awarded $5200.
The authority declined to make an order for loss of dignity and injury to his feelings, and also reduced the lost wages remedies by 80 per cent because Mr Rusling's actions "substantially contributed towards the situation that gave rise to the personal grievance".
The lawyer representing the company, Mark Beech, said while his client could have handled the situation better, the fact of the matter was that Mr Rusling tested positive for prohibited drug at work.
"From the employer's perspective this decision highlights how fraught it can be for employers dealing with drug use in the workplace.
"However, (the company) believes that the lack of damages awarded has vindicated the stance that it took."
Mr Rusling and his lawyer could not be reached for comment.
