NHS staff are being warned not to wear their lanyards when driving or travelling in cars because of the risk of injury if an airbag goes off.
It comes after an NHS worker, who crashed while driving home, suffered a perforated bowel from keys attached to her lanyard.
Another driver suffered a collapsed lung after the lanyard and pass was pushed into their chest.
Staff at Public Health Wales and at least one school have also been warned.
Tim Harrison, chair of the NHS Wales Health and Safety Management Steering Group, said: "Following some traffic accidents across the UK where the wearing of identity lanyards has exacerbated the severity of the injuries sustained, we have taken the step to ensure NHS Wales staff are aware of the hazard.
"This type of accident is unlikely, but we hope by raising awareness of the potential risk, NHS Wales staff who routinely wear these for work will remove their lanyard when travelling in a vehicle."