Fourth fire at V10 Polymers plastics in Blackburn
A fourth fire in less than three months at a former waste plastics site is under control, said the fire service.
About 12,000 tons of waste was ablaze at the former V10 Polymers building in Paterson Street, Blackburn, which started at about 05:00 GMT.
Blackburn with Darwen Council said it was "frustrated" by the series of fires which are being investigated.
A previous owner is being prosecuted by the Environment Agency over the management of the site.
He is due at Blackburn Magistrates' Court on Tuesday.
The fire service said residents have been allowed home after a "handful" of buildings had been evacuated and it was reducing the cordon.
Councillor Sayyed Osman of Blackburn with Darwen Council said the authority had been left "frustrated" by the series of fires but was working with other agencies to "minimise the impact... and disruption" to the local community.
He said smoke coming from the site was being tested and specialists were on site clearing up asbestos debris "for public reassurance".
The waste recycling site has not been operating for some time but it still contained highly flammable waste plastics.
Police said a "complex" investigation was under way into how the fires started but Insp Abid Khan of Lancashire Police ruled out suggestions that children were responsible.
"I think there's more to it than that," he said.
"A number of security measures have been put in place to prevent certainly young children from getting in there... and I'm relatively reassured it was probably not young kids committing these offences... not at four and five in the morning."