About 260 inmates, apparently upset about prison overcrowding after some of them watched a TV show on the subject, set fires and damaged the Essex County prison Monday night before returning to their cells about one hour later, authorities said.

Police officers from five area cities and 20 state troopers were called in to control the disturbance at the medium-security facility, which began between 8:30 and 9:00 p.m. EST and ended by 10 p.m., said State Trooper Byron Rizos."This was the most serious disturbance they've had there in years," Rizos said. "We've responded to small fires there last summer and fall, but nothing of this magnitude."

Essex County Sheriff Charles Reardon said about 90 percent of the prison's 290 inmates participated in setting fires, smashing water pipes and tearing down grates and railings.