Police investigating the devastating Pembroke Refinery explosion that killed four people last year are considering bringing manslaughter charges, today's (Wednesday) print edition of the Western Telegraph has exclusively revealed.

It was on June 2nd 2011 that a blast ripped through a storage tank at the then Chevron refinery.

The explosion killed Julie Schmitz (nee Jones) from Pembroke and Milford Haven men Andrew Jenkins, Dennis Riley, and Robert Broome. The four victims had 12 children between them.

Since then a painstaking investigation has been carried out by Dyfed-Powys Police and the Health and Safety Executive (HSE).

The Western Telegraph has now learned that police are considering bringing charges of manslaughter by gross negligence.

Two employees of Valero Energy Limited - the company that now operates the refinery - have been interviewed under caution in relation to the investigation.

A police spokesman said: "Dyfed Powys Police can confirm that on Tuesday February 7th 2012 they interviewed a second employee of Valero Energy Limited under caution at Haverfordwest Police Station in connection with the explosion at the Refinery in Pembroke, which occurred on the 2nd of June 2011 killing four workers and seriously injuring one other.

"This person was interviewed in relation to potential offences of Manslaughter by Gross Negligence. This is the second person interviewed under caution during this enquiry, the first employee of Valero Energy Limited, also interviewed in relation to potential offences of Manslaughter by Gross Negligence on the 24th of January 2012.

The spokesman added: "This development is very much part of the continuing joint police and HSE investigation which is of an extremely complex nature, and no conclusions should be drawn from it at this stage."

Responding to the development, a Valero spokesman said: "As this refers to an ongoing investigation by the Health & Safety Executive and Dyfed-Powys Police, Valero Energy Ltd can offer no further comment on the explosion at Pembroke Refinery on 2 June 2011, when it was owned and operated by Chevron Limited.

"Both Valero and Chevron continue to provide their full co-operation to the police and HSE in their investigation."

Inquests into the four deaths have been opened and adjourned. A service to remember the victims was held at St David’s Cathedral on November 7th last year.