The United States Environmental Protection Agency (EPA) is investigating the safety of a helmet worn by a man who fell off a motorcycle during a training exercise in Minnesota.
The agency said the incident happened at the Minnesota State University of Health Sciences Center on Oct. 31.
A woman riding a motorcycle on campus was wearing the helmet, which had a valve to stop the flow of voltage from the helmet to the rider’s body, the EPA said.
The rider suffered a head injury and was taken to the hospital, the agency said.
The EPA said the valve is an important part of the helmet system that stops voltage from leaking through the helmet into the body.
It said it is unclear whether the valve can be used by people without a medical condition to stabilize their voltage.
The EPA has not released a list of possible symptoms.