A second man arrested over a large moorland fire on Winter Hill has been released while inquiries continue.
The 20-year-old, from Wigan, had been detained on suspicion of arson with intent to endanger life.
Hundreds of firefighters, aided by helicopter crews, have been tackling the Lancashire blaze since 28 June.
Another man, 22, from Bolton, was arrested the following day on suspicion of the same offence and has been released under investigation.
The blaze has been burning near major communication masts, which transmit TV services to north-west England.
Fire crews have created an exclusion zone to encourage people to stay away.
They said people were still visiting the site, at a popular beauty spot after a used disposable barbecue was found on unburnt land nearby.
Steve Morgan, from Lancashire fire service, said it "beggars belief" someone would risk causing another huge fire.
The exclusion zone covers 3 sq miles (8 sq km) from Pigeon Tower, Rivington, to Wilton Quarries near Bolton.
Russell Hedley, from the Woodland Trust, said whole ecosystems had been wiped out by the blaze.
Crews from around the country joined local firefighters to tackle the flames and another blaze 30 miles away at Saddleworth Moor.
Soldiers sent to assist crews at Saddleworth for the past week were stood down on Friday because firefighters are "making good progress", a Manchester fire service spokesperson said.
Local residents have been told to keep windows and doors shut as both fires have led to smoke and ash across the region.