Deputies were called to check on a possible body spotted in a dairy lagoon on Worden Avenue near Highway 99, west of Le Grand.
Divers from the Merced County Sheriff's Office Water Rescue and Recovery team were able to recover the body. A Cal Fire hazardous material team then helped decontaminate them.
Authorities said the person who died was a male, but they are not releasing any other details as the investigation continues.
Anyone with information is asked to contact the Merced County Sheriff's Office.