Federal investigators have released their final report on last year's deadly gas explosion in East Harlem. 

National Transportation Safety Board investigators place blame on failed infrastructure located near the two ow-leveled buildings—once located between East 116th and 117th Streets.

The board looked at two contributing factors: an underground gas pipe and a broken sewer main that had not been repaired for eight years. 

The agency is also pointing its finger at several city and state agencies, saying negligence also played a role.

Investigators are specifically singling out gas supply company, Con Edison.

The board says recommended repairs were not made a priority—and that it's public safety response program is flawed. 

"The analysis concluded that the FDNY arrival at the accident scene could have occurred about 9:15, at which time the FDNY then could have initiated an evacuation of the area about 15 minutes before the explosion,"  said NTSB Investigator Richard Downs.

"Approximately 20 minutes before the accident, Con Edison received a call of inside and outside gas odor from a resident in the building next to the destroyed buildings. However the Fire Department was not notified as is required by Con Edison's response procedure," said NTSB Lead Investigator Ravindra Chhatre.

Con-Edison is suing the city, saying ITS failure to act led to the explosion.

The suit says the city Transportation Department was told about depressions in the street that were a sign of erosio—and claims that allowed the gas lines to be compromised by water, rocks, and other debris.

A spokesman for the City Law Department said it has not received the lawsuit and would not comment.

The National Transportation Safety board spent more than a year investigating the March 2014 blast, that killed eight people and injured 50 others.