Police have uncovered what they believe to be a drugs factory in a village in the Derbyshire Peak District.
Chemicals and equipment used to produce crystal meth were found
An industrial unit owner in Stoney Middleton reported his suspicions of a man renting the premises.
Officers say they found chemicals and equipment used to make "crystal meth". Police plan to check two other premises in Chesterfield.
The production operation is thought to be only the fourth crystal meth factory found in England and Wales.
Police believe some chemicals may have been dumped in woods near the Rock Mill Business Park and have advised walkers to avoid the area until officers have checked it.
They said the chemicals can be volatile and dangerous if inhaled.
Det Ch Insp Tony Blockley said: "This is likely to be a long investigation as we are having to take care not to put our officers or the public at risk from these chemicals."
Steve Holme, chair of the local community Safety Partnership Drug and Alcohol Action (SPODA) group, added: "It's very worrying that we've discovered the manufacture of this drug in our area although we have no reports that the use of it is prevalent."