Three persons were arrested on Thursday after five workers died and eight others were injured in a boiler blast at a sugar mill in Bihar's Gopalganj district, officials said.The arrested include the mill's owner Mahmud Ali and his two sons, said a district police official.Taking note of the incident, Chief Minister Nitish Kumar ordered a high level probe into it and announced a compensation of Rs 4 lakh each to the victims families."The blast occurred on Wednesday night at the mill in Sadamusa when workers were on duty," a police official said. All the injured were admitted to hospitals.Angry over the deaths, hundreds of locals protested and set ablaze vehicles of the mill owner parked in the premises on Thursday.Rashtriya Janata Dal chief Lalu Prasad, whose home district is Gopalganj, expressed grief over the incident and appealed to the people to maintain peace.