At least 22 passengers were injured after the bus they were riding fell into a 20-meter ravine along the national highway in Kiangan town, Ifugao province, police said Sunday. Ifugao provincial police director Senior Superintendent Laurence Mombael said the KMS Bus Lines bound for Baguio City fell into the ravine at about 4:30 A.M. in the village of Hucab in Kiangan. Eight passengers sustained serious injuries and are being treated at the Ifugao Provincial Hospital. Fourteen others sustained slight injuries and were sent home after receiving initial treatment, the police said. Local policemen were investigating the incident to determine the cause of the road accident.