A 36-year-old motorcyclist from the Swindon area has died at Pembrey racing circuit near Llanelli, west Wales.
The circuit hosts different kinds of motorsport
Mile Tripp, 36, from Swindon, was killed on Sunday when his motorcycle collided with four other competitors shortly before 1500 GMT.
Two other motorcyclists were taken by ambulance to hospital but their injuries are not thought to be serious.
Dyfed Powys Police, race circuit officials and Carmarthenshire County Council are investigating the incident.
The Pembrey circuit was hosting a championship meeting of the NG racing club - it was their first event of the season.
The man died at the scene. The other injured motorcyclists were taken to the West Wales General Hospital.
Carmarthenshire County Council head of public protection Philip Davies said: "Specialist health and safety officers from the public protection department visited the scene shortly after the fatal accident on Sunday.
"We are working very closely with the police and the coroner's officer to establish the cause - we will release a report as soon as that is completed."
He added that local authorities were the enforcing authority for health and safety matters at motor sports events.
The manager of the circuit has said it has one of the best safety records in the UK.
Phil Davies said he did not think the investigations were likely to criticise the circuit's safety measures.