A blaze has broken out at the Tata Steel plant in Port Talbot.
Mid and West Wales Fire Service said it was alerted shortly after 8am.
Images on social media showed flames and smoke coming from the site.
A spokeswoman for the fire service said: "We have got six appliances there from Port Talbot, Neath, Morriston and an aerial appliance from Swansea West.
"As it stands this is an isolated incident and the power supply has been re-established. The crews are on standby just in case anything should escalate."
Last month, Tata announced 750 job cuts at the site, among 1,050 across the UK.