The Environment Agency will review fire safety at a recycling centre hit by a major blaze.
The fire at Universal Recycling in Kilnhurst, South Yorkhsire, burned for two days from Monday.
South Yorkshire Fire Service said the blaze was accidental and caused by machinery.
Environment Agency officials have previously had to intervene at the site following complaints from neighbours about dust and noise.
During the fire, up to 500 tonnes of burning plastic, metals and other materials sent a plume of thick black smoke hundreds of metres in the air, visible for miles.
After the fire service announced the fire was accidental, Mark Readman tweeted: "The stockpiling of such quantities of combustable noxious fume emitting material in a residential area was not accidental."
The Environment Agency said that following its previous intervention, the company had "taken steps to make improvements including updating equipment and improving their operating procedures".
It said it would now consider whether further action needed to be taken and would "review the site's fire prevention plan".