The incident took place at village Hollanbhata under Turekela police station last evening when the detonator planted in the quarry by labourers suddenly exploded, Sub-Divisional Police Officer (Titlagarh) Dilip Purohit said.
The deceased were identified as Pramod Kanda (20), owner of the land where the stone quarry was located, and three labourers - Kailash Majhi (27), Bhakta Bachha (27) of village Hollanbhata and Siddhesh Chhatria of Bhalu Panda village under Bangamunda police station, Purohit said.
While the exact cause of the blast was yet to be ascertained, short circuit was suspected to be the reason, police said, adding investigation was in progress.
With locals alleging that the quarry was functioning without proper legal authorisation, police was verifying the matter, sources said.