Early-morning raids took place yesterday by police and Environment Agency officers at suspected illegal waste sites across West and South Yorkshire and Humberside.
The raids were part of Operation Dance, which is a complex investigation into suspected waste offences by a Leeds-based company and its directors.
Twenty-one Environment Agency officers supported by police swooped on several sites as part of the investigation into illegal storing and dumping of waste.
Five people were arrested as a result of the raids.
Environment Agency lead investigator for the case Damien Ashby said: “Our environmental crime teams target organisations and organised criminals who risk damaging our health, the environment and the livelihoods of legitimate operators.”