An apparent gas leak lead to an explosion Thursday night that destroyed the McDonald’s restaurant in Encinitas, authorities said.

Fire crews were still on the scene early Friday afternoon to survey the damage. The apparent blast lead to a three-alarm fire around 9:30 p.m. Thursday night, authorities said. All restaurant patrons and employees escaped.

The restaurant had been an institution in Encinitas since the mid-1970s.

An investigation is ongoing.