The union leader, Naresh Srivastava (50) succumbed in the wee hours today during treatment at Patna Medical College and Hospital (PMCH), East Champaran district's Civil Surgeon Prashant Kumar said.
Two workers of the mill had yesterday set themselves afire during a protest following which they were rushed to a nearby hospital and later shifted to PMCH.
"His body will be brought to district headquarters this evening after post-mortem," Kumar said.
Meanwhile, Srivastava's brother - Brajesh Kumar Srivastava has alleged that his brother did not receive proper treatment.
Protests erupted yesterday with workers demanding payment of their arrears and reopening of the sugar mill. They also clashed with the police personnel, injuring five of them. The police had to fire three rounds in the air and lob tear gas shells to disperse the unruly crowd.
An FIR was lodged against 20 people, seven of whom have been arrested so far, Superintendent of Police Jitendra Rana said.