The relationship between him and Anderson broke down after an accident on February 7 last year.
Anderson was cleaning out the drum of a concrete mixer and preparing the compressed-air tool he was going to use.
He said he removed his safety glasses because it was a hot day and they had fogged up.
When he started using the tool, a steel connector burst off the air hose and struck him in the eye.
Anderson was taken to hospital where he was treated for the injury and signed off work until February 19.
But days later, he was summoned to a meeting with Campbell and operations manager Michael Clarke.
It was alleged other employees saw Anderson ''have a bit of a fit'', which caused the incident.
The worker denied that was the case and said Campbell got ''very angry'' during the meeting about the lack of paperwork the man had from the hospital.
The pair, according to Anderson, then briefly consulted and quickly dismissed him, told him to gather his tools and leave the company's business premises.
''It is very clear from the disciplinary meeting that neither Campbell nor Clarke considered anything Anderson said, before they decided to dismiss him,'' van Keulen said in his judgement released this week.
He noted, despite a suggestion other employees saw Anderson acting out, there were no witness statements from them.
Valley Crates did not sufficiently investigate the matter, did not give Anderson relevant information, did not genuinely consider his explanation and failed to give him the opportunity to respond before confirming dismissal, he found.
The ERA said the impact on Anderson had been ''reasonably significant''.
''He changed from being an outgoing, bubbly person to being a quiet and unsociable person who did not go out and did not discuss what had happened,'' van Keulen said.
Valley Crates was ordered to pay $15,000 compensation, $11,700 for lost earnings, $1949 wage arrears and $2750 for the former employee's legal costs.
- Otago Daily Times