Seven labourers were injured when a four-storey building housing a small scale industrial unit on Monday night collapsed in Chikhli area on the city outskirts at Kalamna.
Rescue operations are in full swing to extricate a number of persons feared trapped under the debris, police said.
The dilapidated building housing a cold storage plant caved in in the evening following which labourers working there were trapped under the rubble, they said, adding seven workers have so far been rescued and being rushed to Mayo General Hospital.
The identity of the injured has not been established yet.
According to police, due to the impact, the plant machinery suffered an extensive damage resulting into the leakage of Ammonium and carbon dioxide gases causing brief panic in the nearby residential areas.
Many of the residents complained of uneasiness and irritation of eyes due to the leakage which is brought under control, they said.
Power supply was disrupted in the area post collapse and fire brigade and police teams have launched massive rescue operations, added police.