Three people were hospitalized Tuesday because of a gas leak at a Novato fast-food restaurant, authorities said.

The leak was reported at Taco Bell at 930 Seventh St. about 10:30 a.m. The gas leak was contained to the building, according to Battalion Chief Gerald McCarthy of the Novato Fire District.

Three people — including at least one customer — who complained of headache, throat irritation and lightheadedness were taken to a hospital as a precaution, said district spokeswoman Sandy Wargo.

Pacific Gas and Electric Co. crews determined that a gas valve in the heating and air conditioning system that opens and closes manually as the pressure changes had been stuck in the open position, Wargo said.