The families of four people killed at the then Chevron Pembroke Refinery have spoken out after two companies were sentenced for Health and Safety offences.

Valero - which bought the Pembroke Refinery following the explosion in June 2011 - was fined £5m plus £1m costs.

Chevron will pay the fine and costs.

B&A Contracts Ltd, was fined £120,000 and ordered to pay cost of £40,000.

Following the case, the families issued the following statement: "Today two companies, Chevron and B&A Contracts Ltd, were convicted of criminal offences that caused the deaths of our much loved family members; Robert Broome, Andrew Jenkins, Julie Jones and Denny Riley at the Pembroke Refinery on Thursday June 2, 2011.

"The past eight years leading to this conviction have been a very difficult time for all the families who lost loved ones in the explosion.

"It is a blessing that Andrew Phillips survived the terrible events of that day.

"He suffered life changing injuries and he and his family have shared the pain we all feel.

"Andrew, Denny, Julie and Robert were at the hearts of our families and are loved and missed by wives, partners, children, grandchildren, parents, brothers and sisters. They are in our thoughts and are missed every day.

"Although it has been long, the investigation has been very thorough and we would like to thank the Police and HSE investigation team who brought this matter to court and our family liaison officers who supported us throughout the years.

"We would also like to thank the Judge for the attentive and sensitive manner in which he dealt with the sentencing hearing.

"It is clear from what we have heard that the explosion should never have happened. It has been shocking to hear the list of errors that led to the deaths of our loved ones. It is clear that the explosion was preventable and that no one should have lost their life.

"Our lives have been changed forever. We hope that the companies have learned from this tragedy and that changes to their working practices will prevent anything like this happening again and spare others having to suffer what we have."