Police believe they may have uncovered a Methamphetamine factory in a house in Rotherham.
A spokeswoman for South Yorkshire Police said tests are still being carried out on substances found in a house in Broom Valley Road, Broom, earlier today but it is believed that officers have uncovered a drug production den.
Police, firefighters and paramedics remain at the house, around which a cordon is in place as a safety precaution.
Three men and a woman have been arrested on suspicion of drug production.
Three suspects were arrested last night and one more this morning.
The police spokeswoman said: "We’re still awaiting test results on the drugs but officers believe it could be Methamphetamine."
Methamphetamine, also called meth, crystal, chalk, and ice, is an addictive stimulant drug that is chemically similar to amphetamine.
It takes the form of a white, odorless, bitter-tasting crystalline powder.
The drug is taken orally, smoked, snorted, or dissolved in water or alcohol and injected.