A former chief of the Coventry Volunteer Fire Association and a lieutenant have been charged with sexual assault on allegations they had sex with teenage members of the department. Joseph Carilli, the former chief, was charged with second-degree sexual assault and risk of injury to a minor. Carilli, 53, was held on $500,000 bond. His lawyer did not immediately return a call seeking comment. Lieutenant Joe Fragoso, 35, was charged with second-degree sexual assault. Fragoso was released on $250,000 bond. He did not immediately return a call. Police said the two men had sexual relations with teenagers in the department’s junior firefighters program. Teenagers between the ages of 14 and 17 participate in training, emergency calls, and public education. Carilli was chief from 2006 to 2012 and was also the department’s training officer.