Four people were displaced from their Pleasanton homes after a fire damaged two apartment units early Saturday morning, said an official with the Livermore-Pleasanton Fire Department.

The fire started around 1 a.m. in a back balcony of the 12-unit apartment complex on 3845 Vineyard Avenue and spread into two of the apartments, according to Battalion Chief Kurtis Dickey, who said he called a second alarm on the fire.

“The entire building was evacuated for a couple of hours last night,” Dickey said.

No one was injured in the fire but one of the units underwent “major damage,” according to the fire chief. The damaged residences are off Vine Street in an area with multiple other apartment buildings, Dickey said, which made locating the fire somewhat challenging., But he praised the firefighters for quickly finding and putting out the blaze.

“The crews did an outstanding job,” he said.

The fire is currently under investigation and the cause has not yet been determined.