Raipur, Sep 23 - At least 15 workers were killed and some 50 were trapped under debris when a chimney of the 1,200 MW under-construction power plant of Bharat Aluminium Company Ltd (Balco) collapsed in Chhattisgarh's Korba town Wednesday, police said.

The disaster took place when about 100 workers and engineers were engaged in the construction work at Balco Nagar area, some 250 km north of state capital Raipur.

'It's a massive accident that has claimed at least 15 lives. We have launched a rescue and relief operation to save about 50 workers and engineers trapped under the collapsed chimney's debris,' Ratanlal Dangi, district superintendent of police, told IANS by telephone.