There are still dozens of firefighters on the scene of the East Village explosion that affected four buildings along Second Avenue near 7th Street. Twenty-five people, including five "uniformed personnel," have suffered injuries; four people are critically injured.

Two buildings, 121 and 123 Second Avenue, collapsed after the 3:17 p.m. explosion and ensuing seven-alarm fire, and 119 Second Avenue had partially collapsed. Residents, commercial tenants like restaurant Sushi Park at 121 Second Avenue and passers-by scrambled to get out of the buildings after the blast and before the collapse. The rest of 119 Second Avenue was brought down overnight due to fears of further collapse.

At this point, the city believes that gas work being done at 121 Second Avenue caused the blast. Mayor Bill de Blasio said, "Con Ed inspectors arrived at the site earlier for a separate reason entirely, found the work to be unacceptable, gave instructions as to what changes were needed—and that was an hour or more before the explosion."

WCBS 2 interviewed Con Ed CEO Craig Ivey, who explained that the Con Ed crew was checking on a new meter installation, because the building wanted "larger service."

The new installation did not pass inspection and was not ready for gas to be introduced, Ivey said.

“The work failed our inspection for several reasons, including insufficient spacing for the installation of the meter in the basement,” a statement from the utility company reads. “A survey conducted yesterday of the gas mains on the block found no leaks. We continue to work with all agencies on the investigation into the cause, and we are praying for the recovery of all the injured.”

Carlos Torres, the vice president of emergency management for Con Ed, spoke exclusively to CBS2 investigative producer John Doyle about the private contractor doing the work to install the new gas system.

Torres: “There was no leak. There was no leak at the time we were there.”

CBS2: “But you were there to inspect the pipes?”

Torres: “The new piping.”

CBS2: “The Japanese restaurant had installed these pipes.”

Torres: “I guess the plumber for the Japanese restaurant.”

CBS2: “And your guys said, ‘This is no good,’ so what happens next?”

Torres: “Nothing, Nothing changed the status of the piping, and we left. We did what had to be done. We took pictures, and what we do is we go back and explain to them why they didn’t inspect.”

Con Edison said the work failed the inspection partly because the space for a new gas meter was not big enough.

DNAinfo spoke a contractor

who says he hadn't done any gas work at 121, but was checking a gas odor in the basement. Dilber Kubic said "he and the son of the [building] owner ...had just opened the building’s basement door to check a gas odor when the room blew up, knocking them off their feet and sending debris raining down on them."

Kubic suffered burns and smoke inhalation, and said from the hospital, "As soon as we opened the basement door, there was an explosion, a fire. It was full of smoke. The debris was on top of me." DNAinfo points out that Kubic is also under investigation for allegedly bribing Department of Buildings inspectors.

The NYC Department of Health issued a statement about the air quality:

The explosion, fire and building collapse on 2nd Avenue and 7th Street affected air quality for a period of time, increasing the amount of pollution in the air. The greatest impact occurred close to the buildings, but the plume from the fire affected the neighborhood for several hours. New York State monitors showed a rise in particulates in the East Village that peaked around 4 p.m., but has declined to more typical levels since. Wearing respirators (N-95s) or surgical masks is not necessary.

While the Department advised residents to avoid smoke exposure, short-term exposure to elevated particulates did not pose a significant risk to the public. We continue to encourage people who are sensitive to keep away from the immediate area as the fire smolders, and anyone with asthma or heart conditions that experiences shortness of breath or chest pains should seek medical attention immediately. Additionally, the odor will linger in the area for far longer than the air pollution associated with this fire, and while uncomfortable for some, does not pose a risk to the public.

For more information, please visit www.nyc.gov/health

The Red Cross says that they met with 80 residents last night at the relief center in P.S. 63 and provided emergency shelter to those who needed it. The center, which was open all night, closed this morning, but there's now a Resident Services Center for affected residents at Tompkins Square Branch Library, located at 331 East 10th St.

City Council Member Rosie Mendez's offices says, "Residents should go to Thompkins Square Library... The Red Cross is working with residents to support any needs and services they might have. The Emergency Response Unity of the Small Business Services will be working with OEM to reach out to impacted businesses and advise of services to assist."