A huge inferno which saw hundreds of tons of timber alight for more than 24 hours is suspected to be a result of an arson attack, the fire service have said.
The blaze, which police are now expected to investigate, broke out at Bloomfield Recycling in Tipton on Sunday afternoon.
A spokesman from West Midlands Fire Service said: "Following investigations the fire is suspected to be arson. The police are now expected to be investigating the incident."
Firefighters last night carried out an overnight vigil at the Bloomfield Road site with diggers brought in to pull out much of the still smouldering waste after the blaze was brought under control.
The operation was done so that the burnt material could be dampened down to stop it re-igniting and prevent another fire from breaking out.
Fifteen fire crews were called to tackle the blaze at its height. As of last night only three remained.
At the height of the blaze, crews used manned and unmanned monitor hoses, which were being constantly fed by around 8,000 litres of water a minute from the neighbouring canal, to wet the wood which had been burning continuously for more than 24 hours.
When the fire broke out the plume of smoke could be seen from around five miles away, prompting the fire service to advise residents to close their windows and doors.
Engineers from South Staffordshire Water were called to increase the water pressure, while traffic on the road outside the plant was also affected, as firefighters ran hoses from one side to the other in order to access fire hydrants.
By this morning more than 2.5 million litres of water had been poured onto the fire as fire crews battled to keep the blaze under control.
This is the third fire at the site in seven years, with the last one taking place in 2011.