Tesla shares fell Friday after news of another California state government probe into a workplace injury days after the same agency said it would look into workplace safety at Tesla's facilities.

California's Occupational Safety and Health Administration, or Cal-OSHA, confirmed the investigation.

"Cal/OSHA on Thursday, April 12 opened a multi-employer accident investigation with the Kansas City, Missouri-based subcontractor and with Tesla," said a statement from the agency. "Cal/OSHA is investigating the cause of the incident and has six months to issue citations for any violations of workplace safety regulations."

The news was first reported by Bloomberg.

A worker employed by subcontractor Automatic Systems reportedly broke his jaw when he was hit by a skid carrier at Tesla's assembly plant in Fremont, California.

Tesla shares were down 2.7 percent midafternoon Friday.