NEW YORK (CBSNewYork)Gov. Kathy Hochul has announced the findings of an investigation into the subway power outage on August 29.

It shut down half of the city’s subway system, and impacted trains on the 1, 2, 3, 4, 5, 6, 7 lines, and the L train.

READ MORE: New Video Shows Crowd Duck For Cover During Shooting Outside Inwood Bar

Hochul says it was caused by human error.

READ MORE: COVID Vaccine Mandate For New York City Teachers To Take Effect After Federal Appeals Court Lifts Temporary Ban

The MTA’s Acting Chair and CEO Janno Lieber says the battery backup system kicked in, but a mistake was made.

“It appears that a button was pushed accidentally that was not supposed to be pushed. One, that can’t happen, that somebody does something wrong because of lack of training or proper protocols. Two, there have to be interventions that prevent people from hitting the wrong button,” Lieber said.

MORE NEWS: R. Kelly Found Guilty Of All Counts In Sex Trafficking, Racketeering Trial

As a result of the investigation, Hochul is directing a full review of control centers to identify any other potential weaknesses in the system.