Three men aged 37, 41 and 48 were arrested on 19 November and another 41-year-old man and 44-year-old woman from Bolton were detained earlier today (23 November). All have been apprehended on suspicion of committing environmental offences and bailed until 2 March.
Police, with help from the Environment Agency officers, raided homes and industrial areas in Lancashire, County Durham and Merseyside after three abandoned lorry trailers loaded with 96 large drums containing chemicals including acids, solvents and pharmaceuticals were found.
EA senior environmental crime officer Eddie Platt said: Dumping waste illegally puts human health and wildlife at risk and undermines the legitimate waste industry.
Our message today is simple: waste crime will not be tolerated and every effort will be made to arrest, convict and punish those involved.
Nine sites were targeted in the raids and EA officers suspect at least three of them were used to handle the waste.
The dangerous chemicals inside the drums need to undergo a number of specialist treatments before disposal to prevent harm to the environment.
Dumping waste illegally carries a penalty of up to five years in prison and unlimited fines.