Waterways managers are working to stop another pollution incident in stretch of a canal where thousands of litres of cyanide were leaked last month.

About 4,000 litres (879 gallons) of sodium cyanide and other chemicals spilled into the canal in Walsall on 12 August, closing a 12-mile stretch of the waterway.

Walsall Council said aeration of the canal to deal with the problem had since been successful.

“[But] the next step is, what’s the pollution level like in all the sediment that lies at the bottom of the canal,” said Henriette Breukelaar, from the Canal and River Trust.