The Health and Safety Executive (HSE) is to bring charges over the Chevron Pembroke Refinery explosion that killed four people in 2011.

The charges relate to the deaths of Dennis Riley, Robert Broome, Andrew Jenkins and Julie Jones and major injuries to Andrew Phillips.

The five were all working on the Amine Recovery Unit when an explosion and subsequent fire took place on June 2.

The HSE said : "Valero Energy UK Limited and B & A Contracts Limited are to face charges under Sections 2(1) and 3(1) of the Health and Safety at Work etc Act 1974.

"At the time of the incident the refinery was operated by Chevron Limited, but ownership changed in August 2011.

"The defendants are due to appear at Haverfordwest Magistrates’ Court on 24 September 2018 at 2pm."

HSE’s deputy director field operations, Jane Lassey, said: “Following a painstaking and extremely thorough investigation, much of which was conducted jointly with Dyfed Powys Police, we have concluded that there is sufficient evidence to bring criminal charges.”

A spokesman for Valero, said: "We can confirm we have been informed that the Health & Safety Executive is to bring proceedings against Chevron in relation to the incident at Pembroke Refinery in 2011.

"Valero itself is named as a party to the proceedings simply because of its subsequent acquisition of the refinery."

The Crown Prosecution Service said there was insufficient evidence to pursue charges in 2015 following a four-year inquiry by Dyfed-Powys Police, but the HSE continued with their own investigation.