The employee was in the building for one hour before going home sick that day. The employee hasn't been back to the plant since.
Storey County Manager Austin Osborne didn't confirm to deny that a Tesla employee tested positive, but did say that his office has "not received confirmation that this is a valid, presumptive, or actual case."
Panasonic sent a letter to employees Sunday letting them know of the Tesla employee's positive test, NBC reported. Panasonic was notified of the issue as the company shares the gigafactory with Tesla through an agreement the two companies reached in 2014.
The email added that the specific production area where the individual worked has been cleaned and the company's safety protocol has been activated.
"This has been activated and includes 14-day quarantine for particular employees identified by their EHS team and certain cleaning measures," the email said, according to NBC.
Panasonic said that the area where the Tesla employee worked had no connection to Panasonic's side of the building.
Last week, Storey County announced that Tesla would be reducing its on-site staff by nearly 75% over the coming days. Panasonic has been in the process of shutting down its operations at the gigafactory for the past 10 days.
"Nevada will begin ramping down operations early next week and will then close for 14 days. Employees impacted by the closure will receive full pay and benefits for the 14-day period," Panasonic said in a statement on March 20.
Tesla shares were down 0.3% to $512.80 in trading Monday.