Police said that terrorists targeted the labourers in the Rakh-Momin area of Anantnag.
They were shifted to a hospital where their condition is stated to be stable.
While two of the victims, Sunil Jadav, 40, and Pradeep Pujari, 35, died late last night, the third one, Ajay, 24, passed away this morning.
Three seriously injured persons have so far been rescued from the debris. Teams of Army, NDRF, SDRF, Police, and locals were engaged in the rescue operations.
The injured were taken to MGM Hospital, where two of them are said to be in critical condition.
Terrorists indulging in targetted attacks on outsiders was a worrying factor as the valley was witnessing arrival of a large number of tourists.
The labourers are annoyed with the growing incidents of fatal accidents and thought that the state labour minister will talk with the victim’s families and take up the issue with the plant management and take appropriate action steps. But he went away after attending the seminar and the labourers felt let down.
As investigations unfolded, it was found that Dr Shekhar Saxena, managing director of MC Saxena Group of College, had allegedly lured labourers to pose as patients so that the inspection could be cleared.