Ulsan: Three researchers died of suffocation at a plant of South Korea's Hyundai Motor.According to Namibia Press Agency, the incident occurred while the researchers were conducting vehicle testing at the facility in Ulsan, a southeastern port city.The accident took place around 3:00 p.m. local time (0600 GMT). The researchers were promptly taken to a hospital, but unfortunately, all succumbed to their injuries.Further details about the circumstances leading to the suffocation have not been disclosed. The incident is under investigation to understand the exact cause and potential preventive measures for the future.