A drug lab exploded in a Sydney apartment on Wednesday and 8 officers had been treated for possible exposure to the toxic explosion.

Police reported that the  unit block had been evacuated after the building caught fire at around 11:30 pm Wednesday. They  stated that during the evacuation they located a clandestine drug lab inside the unit, which according to them caused the fire.

A 31-year-old man had been arrested and taken immediately to the Royal North Shore Hospital for treatment of burns caused by the explosion. He was taken to the hospital under police guard reported ABC. The unit which the neighbours described as very quiet otherwise was occupied by a couple and another man.

Inspector Shane Halliday informed that two police officer out of the eight, who got exposure to the toxic expulsion, were tested for chemical contamination. He said, “a number of police officer had to be decontaminated by the fire brigade at the scene, and two were conveyed to the hospital for further treatment.”

He added that after examination of the unit, police located the met lab, which they had completely sealed off and designated a crime scene for further investigation.

Hazmat, NSW Fire and Rescue and the State Crime Command Chemical Operations Unit were informed and they also responded to the scene.

Watch the video after the explosion when the authorities arrieved at the scene here.

In the police statement, the authorities confirmed that the fire damaged several rooms in the unit. Police and fire fighters remained in the scene till Thursday morning.

A resident when interviwed by 9NEWS said: “I heard a commotion outside so I came out into my balcony and people up the building across from my apartment were screaming that there was a fire and we had to get out right now, so I just grabbed my stuff and run.”

It was observed that the apartment building did not have a public address system to alert the residents so people came to know about the fire only after they heard the screams outside.