The explosion occured at the tafflon plant inside the government-owned factory around 11 AM and left a 15-foot deep crater at the spot. A labourer identified as Suresh was injured, they said.
Security was tightened in and around the factory, with three ambulances present at the scene, they added.
The injured worker was taken to Coimbatore Medical College Hospital for treatment.
Investigations are on to ascertain the cause for the blast, police said.