An arbitrator has ruled that Lane County erred in firing an employee for his off-duty use of medical marijuana that he says was based on the recommendation of a doctor for side effects from cancer treatment.

The Register-Guard reports Michael Hirsch will be reinstated as a senior programmer and systems analyst. The county has also been ordered to give him nearly $22,000 in back pay.

Arbitrator Jeffrey Jacobs determined the county hadn’t provided evidence indicating Hirsch had used marijuana at work or that his off-duty use affected his performance.

Hirsch, a 60-year-old prostate cancer survivor, was fired in December after two employees reported smelling marijuana smoke on his clothing.

County spokesman Jason Davis issued a statement saying the county relies on maintaining “a drug-free workplace” to receive federal funds.