ALBANY — Con Edison’s failure to inspect and test a plastic joint in an underground gas pipe led to the 2014 East Harlem building explosion that killed eight people and injured 50, state regulators said Thursday.

The Public Service Commission released a report saying that the company committed several violations, the most crucial being the failure to test, inspect and discover a faulty joint in a section of pipe that had been damaged by faulty city sewer lines.

The state claims that the contractor who welded the joint in 2011 was not properly qualified, as required by state regulations.

On March 12, when Con Ed received two “odor” reports from callers who smelled gas both inside and outside of the Park Avenue building, the utility failed to notify the Fire Department before the explosion, according to the PSC’s report.

“That being said, it is impossible to know for certain whether the FDNY’s arrival would have prevented the East Harlem Incident (and, indeed, the NTSB affirmatively avoided drawing such a conclusion),” the report stated.

However, rules required the company to notify the Fire Department and rush to the scene after two calls, state regulators said.

A Con Ed worker actually called the FDNY at 9:19 a.m., 12 minutes before the explosion — but asked the department’s call-taker to “hold on” before hanging up without explaining the situation, the report says.

The state has ordered the utility to show cause as to why the state should not bring a civil lawsuit and administrative penalties against it.

Con Ed continued to point the finger at the city, highlighting the sewer breach that eroded the joint.

“We maintain that a cracked fitting, damaged by undermined street infrastructure from a pre-existing sewer breach, was the source of the leak that led to the East Harlem gas explosion,” Con Edison said in a statement.

The utility added that it has made significant improvements since the tragedy to prevent future gas blasts.

“We also agree on the importance of doing everything in our control to prevent a tragedy like this from happening again,” the company said in a statement.

“We implemented monthly gas-leak patrols, enhanced response protocols with the Fire Department, and are working closely with the city on coordinating street infrastructure projects.”