The death of 11 people living in basement apartments from floods caused by remnants of Hurricane Ida is prompting the city to take a closer look at the apartments’ safety and legality.

Earlier this month, Ida dumped a reported rate of over three inches an hour of rain. Water filled basement apartments, preventing residents from fleeing. Among the 11 people who died was a family of three that included a 50-year-old man, 48-year-old woman and 2-year-old boy.

Four out of six of the basement apartments where people died were illegal conversions. The apartments are classified as alterations of an existing building to create additional apartment units without first obtaining the proper permits or approval. This also includes illegal cellar apartments, illegal attic apartments and illegal single room occupancies (SRO).

Illegal basement apartments could potentially have a number of safety and quality of life issues including lack of adequate emergency exits, substandard construction, and unsafe gas and electrical systems.

The apartments are often lower in rent and occupied by undocumented immigrants and people looking for affordable housing. The basement apartments where people died during Ida were mostly in Brooklyn and Queens.

As part of Mayor Bill de Blasio’s NYC Climate Driven Rain Response plan announced earlier this month, people living in basement apartments will be subject to special advance warning during severe weather events. Measures include cell phone alerts and even door-to-door evacuations.

Research from the mayor’s office shows that at minimum there are more than 50,000 illegal basement apartments with more than 100,000 people living in them across the city.

“We have an illegal basement problem and then we have a problem that so many people end up in illegal basements are fearful to communicate for fear they might be evicted or, worse in their mind, deported,” de Blasio said. “It’s just an extraordinarily challenging set of circumstances.”

De Blasio said the city’s Housing Department will not be issuing fines to landlords with illegal basement apartments for the rest of the year and tenants will not be evicted.

New York Attorney General Letitia James called on the city to provide special emergency housing vouchers to residents living in unregulated basement apartments. She says the illegal apartments are a result of the ongoing housing crisis in the city and the desperation to find an affordable place to live.

“To prevent these problems in the future, we must also ensure that basement units are safe for human occupancy and regularly inspected,” James said. “Overcoming the twin threats of climate change and a housing crisis will not be simple, but we must ensure measures are in place to protect our neighbors and prevent a future catastrophe.”

Public Advocate Jumaane Williams said direct federal resources are needed for infrastructure to protect people in their homes.

“Basement units are a critical component of meeting the need for housing stock in our city, but it is just as critical that government acts quickly to legalize, regulate, and protect these units and the countless tenants who call them home, including with proper warnings in times of crisis,” he said.

In a statement, Andrew Rudansky, a spokesperson for the city’s Department of Buildings (DOB), said basement apartments are not necessarily dangerous to residents. The DOB has received over 3,100 self-reported notifications of storm-damaged properties in communities across the five boroughs.

“Following the tragic flooding associated with Ida, our focus in the flood-stricken areas of the city has been focused on assisting New Yorkers, and making sure that storm-damaged buildings are structurally stable and safe to occupy,” Rudansky said. “In the interest of protecting our fellow New Yorkers, DOB and our partners at HPD have been conducting safety inspections at these properties to check for structural damage and other immediately perilous collapse conditions.”

Rudansky added that the DOB has not been issuing violations or associated fines related to safety inspections. If inspectors find any storm damage, they notify the property owners of the condition, and provide guidance on repairs and how to remediate any hazardous conditions.

The DOB only issues vacate orders when a building is posing a life safety threat to occupants, not because it is illegal.

“For their own safety and the safety of their family, New Yorkers should seek out safe and legal apartments to call home,” Rudansky said. “Before they sign a lease, New Yorkers should verify if the building they are interested in can be legally occupied as presented by the owner.”

National Homeowner-Landlord Association Executive Director Philip D’Erasmo told the AmNews that the city is targeting landlords with fines and violations. The majority of basement apartments are owned by small landlords with private homes and D’Erasmo says some landlords have been fined hundreds of thousands of dollars.

“One city agency will come to you and say, ‘Oh, can you place this guy, he’s homeless. Can you place them in your basement,’ and they’ll put them there, they’ll pay you for them and then while they’re paying you, another city agency will come in and fine you 10 times what the first agency pays you,” D’Erasmo said. “Probably say that 75% of all buildings have some illegal apartment in the basement.”