A CHEMICAL set-up to produce amphetamine was discovered in a caravan on an industrial estate.
Two men, one from Darfield and one from Platts Common, were arrested on suspicion of producing a controlled drug.
"This is extremely rare - we've never come across it in Barnsley before," said DCI Mark Wilkie.
"They would have needed someone with knowledge of chemistry and someone to get the chemicals.
"We've received lots of different chemicals, the problem is we don't know what they are so they have been sent off for analysis."
The discovery came as part of the month-long 'Operation Barracuda', which has been set up not only to target individuals growing cannabis but to educate the public so they can be on the look out for signs it may be happening in their area.