DIESEL has leaked from a storage tank near Swansea’s River Tawe.
The spill occurred at Swansea Council-owned Pipehouse Wharf, Morfa Road, but it is not clear how much oil escaped.
Mid and West Wales Fire and Rescue Service was among those who responded to the incident.
The council said it was confident there was no risk to public health.
A spokesman said: “The quick actions of council staff have helped contain a recent diesel spill after one of our diesel container tanks suffered a failure to a tap.
“We are satisfied that most all of the diesel which escaped from the tank was contained within the immediate site area and has been pumped back into storage containers.”
He added: “We are continuing to work with a number of agencies including Natural Resources Wales (NRW) and our own pollution control team to monitor the impact of the spillage and we are confident there is no risk to public health.”
NRW environment officer Jamie Wakeford said it attended the scene after being informed of the spill straight away by the council last Wednesday.
He said: “We worked closely and effectively with the council, Mid and West Wales Fire and Rescue Service and oil spill contractors to manage and clean up the spill swiftly.
“While we saw no significant pollution to any nearby watercourses, this incident highlights the potential risk posed by the storage of oil.
“It is essential that oil and fuel tanks are installed and maintained correctly in accordance with the relevant legislation and are subject to regular checks.”