Night shift employees at Yalumba Winery were evacuated from the Angaston site on Wednesday due to a gas leak.
According to SA Country Fire Service spokesperson Dan Hamilton, a hazardous material had been detected at the Eden Valley Road winery at about 10pm resulting in the evacuation of employees.
"The gas detected was ammonia and after crews working in small teams they were able to isolate the source of the leak to a pipe which was part of a compressor," Mr Hamilton explained.
Crews were able to seal the leak and also worked to dissipate the gas from the facility.
The cause is attributed to a small mechanical breakdown and fortunately no injuries were reported.
On Thursday morning crews were assisted by the MFS in monitoring gas levels until it was safe for employees to return to work.