She says the incident at the Borough Hall station could have been avoided.
In June 2018, chunks of debris fell onto the northbound platform for the 4 and 5 trains. One person was hurt.
When looking into the collapse, the inspector general says she found significant flaws in how underground structures are inspected.
According to the report, engineers failed to recognize just how bad the structural defect was that led to the collapse, even though it had been monitored for two years.
She says they also used ineffective testing even after the collapse.
The inspector general also said NYC Transit didn’t implement recommendations issued in a 2010 report that could have prevented extensive station damage and repairs.