The Royal Newfoundland Constabulary is confirming that they found a secret drug lab in a St. John's home, but it's not yet clear what kind of drugs were involved.

Police say the chemicals recovered from the residence will be sent to Montreal for analysis by Health Canada.

Deputy Fire Chief Jerry Peach said the hazmat team that searched the house was walking into the unknown, as illegal labs don’t label substances used to make drugs.

"There was enough of different types of chemicals and different sorts of things in the house that had they not been dealt with as they were, the potential was there for explosion or fire, easily," said Peach.

He said potential poisoning was another risk they faced.

"We know what we’re dealing with is something that’s extremely dangerous to us," said Peach. "That’s why it’s done so slowly."

Paramedics were called to the house late Friday morning to deal with a medical emergency that sent one person to hospital.

Albany Street was shut down for most of Friday while police and firefighters investigated. Residents were evacuated from the area.

Late Friday night, teams from the RNC and RCMP, assisted by firefighters, executed a search warrant at the home.

A "large quantity of chemicals consistent with a drug-manufacturing operation" was recovered, stated an RNC news release.

The lab was dismantled and residents were allowed to return to their homes later Saturday.

Police say the possibility of charges remains.