Initial fears that the cause was related to terrorism were quickly allayed by statements by mayor Michael Bloomberg and other officials shortly after the event.

[8] One of the most significant events occurred near Gramercy Park in 1989, killing two Con Edison workers and one bystander, and causing damage of several million U.S. dollars.

[10] The explosion, which occurred just before 6:00 p.m. local time,[1] near the peak of the evening rush hour, was caused by the failure of a Consolidated Edison 24-inch (0.61 m) underground steam pipe installed in 1924.

[19] The official report released by the utility company on December 27, 2007, cited a combination of factors, accepting responsibility for deficient repair work done by a contractor that ultimately led to the rupture.

[22] They subsequently revised this assessment saying the ruptured pipe "experienced a sudden internal over-pressurization, due to water hammer, at least five times greater than normal.

"[23] There had been persistent steam leaks and related repair activity in the area the weeks and months prior to the explosion,[6] and utility crews had checked the site only six hours before.

[3] Preliminary investigation results showed that a leaking seam repaired just before the disaster was found intact, and the pipe burst suddenly at a location approximately 10 feet (3 m) away.

[2] The New York City Fire Department initially sounded a second alarm, then rapidly ratcheted the event up to a five-alarm response,[5] sending more than 200 firefighters from 40 units, three of whom sustained injuries, along with one police officer reported injured.

[5] The New York City Police Department established a "frozen zone" by cordoning off a several block radius around the site, from 40th to 43rd Streets between Vanderbilt and Third Avenues, restricting pedestrian access.

[30] Although an underground electrical transformer and feeder cables were also damaged, there were no significant power outages reported, but customers in the affected area were asked to reduce demand.

Subway service was restored overnight, before the next morning's rush hour, with all trains initially bypassing the Grand Central – 42nd Street station.

[31] Grand Central Terminal was also at least partially evacuated in the immediate aftermath,[13] and entrances facing the affected area were closed, but Metro-North Railroad commuter train service was not significantly disrupted.

An extended environmental clean-up would have significant adverse transportation and economic impact, because the site is in one of the busiest sections of the city, and one of the most expensive commercial districts in the U.S.[6]More than 700,000 commuters pass through nearby Grand Central each work day.

Businesses in the frozen zone were severely impacted, with financial loss estimates as high as US$30,000,000,[3] which could have reached into the hundreds of millions if the clean-up went beyond one week.

[16] In a twist labeled as ironic by a city lawmaker, a law firm that has Con Edison among its lobbying clients was one of many businesses whose offices were inaccessible due to the frozen zones.

[19] A Brooklyn woman was the first to file a lawsuit against the utility, claiming she was traumatized by the blast, which had reminded her of her sister's death in the attacks on the World Trade Center.

Gioa's statement said, "they'll do anything they can to deflect blame and avoid taking responsibility, but now this report shows that Con Ed's poor maintenance contributed to this deadly explosion.

In the wake of the New York event, present and past city officials credited the utility for the extended period of safe operations.