Emergency service crews are carrying out an exercise at Waterston today (Thursday) to test emergency plans.

Pembs Fire Command (@PembMAWW) tweeted: "We are participating in an operational exercise in Waterston, Milford Haven.

"There will be increased traffic to the site between 0900 - 1400. We, along with our multiagency partners are helping Valero Pembroke Oil Terminal to test their COMAH (Control of Major Accident Hazards) plan today.

"This is standard good practice and something we do with all our major sites in Pembrokeshire on a rolling program.

"Vital to test our emergency plans to ensure they are effective."

The Waterston site is home to the Dragon LNG facility as well as the former SemLogistics fuel storage site, which was bought by Valero last year.