Following information that some labourers were entering without passes, assistant commandant of CISF Sasanka Sekhar Mohanty, who was monitoring entry at the main gate, prevented them, Additional Superintendent of Police, Paradip, Bijaya Sahu, said.
Angered by this, one of the labourers allegedly kicked Mohanty in the abdomen and in retaliation CISF personnel fired three rounds in which three labourers were injured below the knee, Sahu said.
One of the injured was admitted to the SCB Medical College Hospital at Cuttack and the other two at the government hospital here.
After the labourers dispersed, the CISF personnel dismantled some shops run by people from a local slum which were being used by the labourers for planning protests before the oil refinery, the police said.
At this, slogan-shouting labourers arrived with sticks and agriculture implements, barged into the camp office of the CISF office in front of the refinery and damaged furniture and other goods, but relented after the police reached the spot.
"The situation is now under control and armed police have been deployed in the area," Sahu said.
Leaders of Baidehi Shramik Union led by Jayant Biswal and Purba Bharatiya Taila Visodhanagara Shramika Union led by Santosh Patnaik, alleged that the CISF opened fire on innocent people in which eight labourers were injured.