The New York City Council passed a law Wednesday preventing the use of natural gas and other carbon-based fuels in the construction of new buildings starting in 2024 — a measure expected to not only reduce carbon emissions but also the release of hazardous pollution associated with the consumption of fossil fuels by buildings.

The bill passed the council with 40 in favor, 7 nays and one abstention.

The new legislation is designed to reduce air pollution, cutting carbon emissions by about 2.1 million tons by 2040. That is equal to the annual pollution caused by 450,000 cars. But it doesn’t explicitly forbid the use of natural gas or specify what kind of power to use.

Instead, it caps emissions from building operations to less than 25 kilograms of carbon dioxide per million British thermal units of energy — a limit that makes it next to impossible to be compliant if gas is used. Over 70% of the city’s greenhouse gas pollution comes from building operations such as heat pumps and hot water heaters. Mayor Bill de Blasio is expected to sign the bill into law before he leaves office, as it fits with the city’s goals of zero emissions by 2040 and achieving carbon neutrality by 2050.

While the real estate industry supports and acknowledges that electrifying buildings is inevitable, its representatives think the power grid and other infrastructure need time to mature in order to meet energy and operational demands — the electrical grid is still powered largely by natural gas. They also expressed concerns about the cost-effectiveness for their businesses.

“There are risks to moving too quickly,” said Zach Steinberg, senior vice president of policy at Real Estate Board of New York (REBNY).

Most buildings have a natural gas hookup in addition to receiving electricity from a power grid. This energy is used for heat, hot water and cooking, but architects and environmentalists said these needs can be met by technology that’s already in use, such as electric heat pumps and electric stoves, which they say are affordable to incorporate into design and construction.

But by eliminating the need for a separate gas line, a building is completely reliant on the electricity grid for all its power needs. Steinberg said he is concerned that the current grid cannot handle these power demands for the entire city, but a recent study by the advocacy group Urban Green Council disagreed.

Still, while the grid might be ready, the changes will only count as zero emissions if the power plants connected into the grid stop relying on fossil fuels and pivot to renewable sources such as solar, wind and hydrothermal. The new law is just one step toward forcing those issues on carbon neutrality.

“Designing buildings to be fossil-fuel free is nothing new for architects,” said Adam Roberts, director of policy at American Institute of Architects (AIA). “The claims that the technology does not exist and that the architectural expertise doesn’t exist to design buildings without fossil fuels in New York City – that’s kind of a joke.”

Such modifications have been part of affordable housing design for years, according to Sara Beyer, director of sustainability at Magnusson Architecture and Planning. In fact she has three all-electric buildings under construction and another eight in the design phase. As for the extra costs, Beyer said the technology is used in all her electric buildings, which are affordable housing units.

Other architects pointed out the cost savings by switching from gas to electric. Mark Ginsberg, partner at Curtis + Ginsberg, said that going all electric only adds 2-5% to the overall cost of new construction. Some advocates pushed for the bill to also cover older buildings undergoing renovations but Ginsberg said it’s much more expensive for an existing building that will have to be retrofitted with all new electric service because it will be using more electricity and no gas.

Health benefits will also come from reducing carbon emissions in a state known for its high mortality rates from pollution. RMI, a non-partisan energy policy group, estimated that New York state led the nation in 2017 in premature deaths caused by fuel combustion in buildings. New York City, meanwhile, experiences rates of asthma hospitalizations that are, at best, double what other regions see in the state, and a similar pattern exists for asthma-related deaths.

Safety is another reason to end the use of carbon fuels inside buildings. Roberts said fully electric buildings don’t have the common concerns of explosions and fuel fires that are a real danger during flooding or when people neglect to turn off a gas stove.

The law comes with a few exceptions. Hospitals are exempted because some medical equipment needs to connect to gas in case of a power outage. Back-up generators for emergency power will also continue to be tied to gas because no viable alternative yet exists. The Commissioner of the city’s Department of Buildings, who would oversee enforcement of the law, will also be allowed to grant exemptions based on financial hardship.

The law does not take effect right away. For buildings under seven floors, these regulations will begin with new applications submitted after December 31st, 2023 and July 1st, 2027 for larger construction.

“Climate change is the existential issue of our times,” said Ginsberg. “If anything, we’re blowing it. Although this is going to cause some pain, we’re doing this now, so it’s not impossible. To meet any of the city and state agreements with Paris and Glasgow, we got to be doing this.”