Two people are listed as being unaccounted for as investigators keep looking into Thursday's explosion in the East Village that injured at least 22 people and brought down three buildings.

The cousin of one of the missing people, identified as Nicholas Figueroa, 23, told NY1 they are still holding out hope.

"I just hope he's OK and I hope, I'm praying for the best. I know he's strong and I know he'll overcome anything, so that's what we're praying for right now," said Anthony Figueroa.

Sources say Nicholas Figueroa was on at date at Sushi Park restuarant, paying for a meal, when the explosion happened. Figueroa's date is in the hospital.

Figueroa's relatives said they've searched hospitals without luck.

"Trying to keep our faith strong. find my brother Nicholas, keep hope alive," said Neal Figueroa, Nicholas' brother. "Oldest out of four boys, four handsome young men."

Police have identified the other missing person as Moises Lucon, who they say is 26 years old. Sources say he was at the register.

In the aftermath of the explosion, an off-duty firefighter happened to be in the area and was seen on cellphone video trying to get people out of the buildings before the fire flared up.

Firefighter Mike Shepherd was seen climbing down one of the buildings.

Shepherd said he just finished having lunch in the area when he heard the explosion and rushed to the scene.

"I said, 'I got to go up the fire escape,' and with that, a young woman came out on the third floor screaming and yelling and just hysterical, and I told her, 'Come down,' Shepherd said.

"I asked her, 'Is anybody else upstairs?" and she said, 'I don't know. I want to get out of here.' I said, 'All right.' I just climbed it, started searching my way up.

"I don't know. I'm third-generation, so you know, maybe it's just in your blood. But being a New Yorker, you're always willing to go out and help someone.

"There's an old saying, 'I was scared but I did it anyway.'"

Shepherd said he climbed all the way up to the fourth floor looking for victims until the fire and smoke grew too intense.

In a press briefing Friday, Mayor Bill de Blasio said 22 people were injured in the explosion, including six firefighters.

Four of the injured are in critical condition.

A collapse zone has been set up along Second Avenue between 7th and 8th streets. All buildings and businesses on that block have been evacuated.

Utilities on the block have also been shut off.

Con Edison says it shut off gas service Friday morning to 187 residential and 32 commercial customers in the area.

Mayor Bill de Blasio joined emergency officials for a tour of the scene Friday morning.

Speaking to reporters later in the day, the mayor said preliminary indications still point to a "gas-related" blast.

Private contractors had been working on expanding the private gas line in the building just before the explosion, which occurred at 3:17 p.m. Thursday at 121 Second Avenue, the mayor says.

The president of Con Ed says the utility's inspectors had been at the building at about 2 p.m. checking out the installation of a gas meter but the "installation did not pass inspection." The Con Ed inspectors then left the scene.

The mayor said that 15 minutes after the Con Ed inspectors left, the owner of a sushi restaurant reported smelling gas to the building’s landlord. The landlord then went the building's basement with the contractors, and that is when the explosion occurred.

Sources tell NY1 that last year, it was discovered that someone had tampered with the gas meter, possibly trying to bypass it to avoid paying for gas.

With a new gas system being installed, sources say investigators want to know whether workers were attempting something similar Thursday after Con Ed left the site.

The general contractor, Dilber Kukic, was charged last month with bribing an undercover investigator posing as a city inspector, though police officials say that case is not relevant to this building and that Kukic has been helpful to their investigation.

"He was also, actually helped extricate one of the individuals that was injured," Boyce said.

The city says permits had been previously obtained for work here, including the new gas service, but any work beyond last September had not been permitted.

Con Ed said the building's plumber had failed two inspections.

The mayor on Friday again emphasized the importance of treating any potential gas leak as an emergency, suggesting the first call in this case, as with any smell of gas, should have been to 911.

"Calling anybody else is not the same as calling 911 or calling Con Ed. Those are the only two places that can immediately act," de Blasio said.

While the mayor suggested some nearby buildings could be reinhabited on Sunday, officials warned of a painstaking process. Once the fire is put out, debris must be searched for possible remains.

Health officials say the air quality is back to normal in the area.

The city opened a Resident Service Center at the Tompkins Square Branch Library on East 10th Street.

According to City Councilwoman Rosie Mendez, 11 buildings in the area have evacuation orders. She said that includes 144 apartments.

Mendez says 80 people - 79 adults and one baby - have registered with the Red Cross. She says 30 people - 29 adults and one baby - need a place to stay.

The Mayor's Fund to Advance New York City is now accepting donations to assist those affected by the building collapse in the East Village.

Anyone who wants to donate can visit this link.

The Mayor's Fund is asking people not to drop off any in-kind donations to the area.