A spokeswoman with the Department of Investigation said the agency is "investigating the response times and other related procedures associated with the Queens fire."
The toddlers were staying with relatives at a house on Bay 30th in Far Rockaway when the fire broke out at 11:51 p.m., according to the FDNY. The home didn't have working smoke alarms, officials said.
Although firefighters arrived on scene five minutes later, an ambulance didn't arrive on the scene until 12:13 a.m., according to union officials, and the FDNY admitted an ambulance wasn't dispatched until several minutes after fire officials on scene phoned in a confirmed fire, which is supposed to trigger an automatic response.
Sources estimated that delay was about 8 minutes, and that the cause was likely caused by human error, between when FDNY officials got to the scene and phoned in a confirmed fire and when an ambulance was dispatched.
Mayor de Blasio vowed Tuesday to make changes to the city's emergency response protocol if an investigation found there was a breakdown, and called the delay "unacceptable."
“We need to know, was it something about the system, was it something about the individuals involved. We just need more facts before we can comment,” he said.