The teachers were on their way to Samal Island in Davao del Norte for an excursion when the accident happened at about 8:45 a.m.
The wounded were given treatment at various hospitals in Davao City.
Maximo Bragat, chairman of Barangay Katipunan, Arakan, where the accident happened, said driver Jessie Gabriel, 32, of Casisang, Malaybalay City, apparently lost control of the van while negotiating a well paved but sharp-curved portion of the highway.
The injured teachers were identified as Eduardo Isagayo, Julius Galario, Maria Araceli Mendoza, Clara Eduabe, Joralyn Macabudbiod, Bambi Austral, Ofelia Tigao Aba, Genal Allamba, Leonoro Gilang, Abecia Flordaliza, Jee Ian Lim, Aquilino Gemucon and Chona Nunez.
Five of them were in critical condition, the village official said.
Bragat said the area where the van careened off the road has been known as “accident prone.”
“Almost every week, (an) accident happened there, claiming lives and causing injuries to many,” he said.
Bragat said the village government had put up early warning devices and reminders to motorists but accidents still occur. He also asked motorists to drive apply extra care when driving through Barangay Katipunan.