Two persons, including aboy, died while four others washed away on Saturday when the storage pond of a private coal power plant developed a breach in Harrahwa village in Singaruli district of Madhya Pradesh, an official said.District Collector KVS Choudary said the pond of the Sasan Ultra Mega Power Project (UMPP), located around 20 kms from the district headquarters, broke around 5 am on Saturday.At least six people washed away in the sludge, he said, adding that the bodies of Abhishek Kumar Shah (8) and Dinesh Kumar (35) have been recovered.He said efforts were on to trace Seema Kumari (9), Ankit Kumar (3), Chunkumari (27) and Rajjad Ali (28).When asked about the cause behind the incident, the collector said, "It is sheer negligence on the part of Reliance (Power, which owns the plant)".When asked about the action the administration is proposing to initiate, the collector said, "Our priority right now was to search for the four missing people. A magisterial inquiry has been ordered into the breach," Choudary said.Reaction of Reliance Power was not available immediately.The sludge has affected crops spread over an area of 25 acres, he added.