Police say a dozen students and one teacher have been injured by an explosion in a high school chemistry class in central Germany.

Police spokeswoman Jasmin Kaatz says glass flask containing 1 1/2 liters (2.1 pints) of nitric acid exploded in an 11th-grade class at a high school in Goettingen. Some of the students were injured by the spray of the acid while the teacher and other students inhaled fumes.

Kaatz says all 13 people were taken to the hospital for treatment Monday but none of the injuries was thought to be serious.

The school was evacuated after the explosion and all 1,100 students were sent home. Police are investigating to try to determine the cause of the accident.