The operators of a recycling centre where firefighters have been battling a blaze for five days were already in trouble with the Environment Agency.
The operators of the site on the border of Hemel Hempstead were suspended from importing compost or wood waste there because of poor management. They were also ordered to remove risk of heat, fire and serious pollution.
Herts Fire Service will investigate and the Environment Agency is going to work with them and Herts County Council to decide on the next steps.
The Appspond Lane incident has caused chaos for motorists and neighbours since it started on Saturday night.
Smoke forced highways officials to shut the A414 and the A4147 in both directions between Hemel Hempstead and St Albans until Tuesday afternoon. Yesterday they closed the northbound carriageway of the A414 for a time because of safety issues and people living in Hemel Hempstead Road have been given emergency water supplies since the fire started because firefighters are using up so much water from the hydrants.