Residents in Puerto Plata, Bonao, Santiago, La Vega, San Francisco and Salcedo suffered an eight hour blackout yesterday. The Edenorte power distributor says the blackout was caused when the Smith-Enron power plant of Puerto Plata went out of service. They also attribute the blackout that affected 50% of the Cibao provinces to problems on the Santiago-Canabacoa transmission line. Meanwhile, the Dominican Electricity Corporation said that the blackout should have only affected six circuits and that Edenorte should give a better explanation as to why power was shut off at another 10 circuits. CDE says the problem occurred on the power line from Puerto Plata to Navarette.