HEALDSBURG, Calif. (AP) — State workplace safety officials are investigating the death of a Northern California winery employee who was found unresponsive near a fermentation tank.

Authorities said that 61-year-old Salvador Plaza-Centeno died Tuesday while working at Dry Creek Vineyard in Healdsburg. The Sonoma County Sheriff’s Office said Thursday that emergency personnel declared Plaza-Centeno dead at the scene. An autopsy to determine the cause of death is pending.

The state Department of Industrial Relations, known as Cal/OSHA, said it was notified of the death by an outside source and has opened an investigation. A Dry Creek Vineyard spokeswoman says Plaza-Centeno had a medical emergency while working.