The Environment Agency have been checking oxygen levels in the Birmingham canal following a major fire at a recycling plant in Smethwick yesterday.
The body said its "primary concern" was to ensure the protection of the environment and the local community.
Working with West Midlands Fire Service, Severn Trent Water and the Canal & River Trust, the Agency has tried to minimise any fire water run-off entering the canal, with most being contained and pumped into the sewer.
Northamptonshire's Arson Task Force is warning local residents about floating lanterns following the fire at a Smethwick recycling plant.
Around 50,000 tonnes of plastic recycling material and a factory is on fire in Smethwick.