NYC's new rat-killing weapon is wildly successful — for now

• New York City's new rat-killing method has wiped out rats on a strip in the Upper East Side.
• The carbon-monoxide method kills the rats but doesn't address the underlying issues.

New York City has deployed a new method for killing rats that's so effective, nearly every targeted rat has died — but that doesn't mean the city's solved its notorious rat problem for good.

The method involves pumping carbon monoxide into rat burrows, ultimately suffocating the rodents inside. "It's very quick," Matt Deodato, an exterminator and the owner of Urban Pest Management, previously told Insider. "It's effective."

The carbon-monoxide method successfully eliminated about 100 burrows on a stretch of East 86th Street on the Upper East Side of Manhattan, and there are already plans to try it in new areas.

Still, it will likely take a lot more than that to take out New York City's rats for good.

Jason Munshi-South, a biologist at Fordham University who studies urban rats, told Insider that while the carbon-monoxide method will kill the rats in the targeted burrows, it's a "limited strategy" that will result in a "limited victory."

"If you haven't solved the underlying issues of access to food and garbage and harborage for the rats to nest in, then they will come back," he said.

Even if you kill rats inhabiting burrows in parks or near buildings, other rats from nearby could eventually move in, or any survivors from the targeted burrow could reproduce and repopulate it.

Munshi-South said the city has used similar methods in the past, including dry ice in lower Manhattan parks with hundreds of rat burrows. Through the daily, intensive use of dry ice and monitoring, this method reduced the number of burrows to only a few.

"But if you stop doing that for a period of time and come back next year, the rats are thriving again," he said. "So that's why it's a limited strategy."

Deodato agreed that the method is not a permanent solution, adding that you also need to eliminate the rats' food supplies and places for them to nest to keep any from coming back.

Munshi-South said users can only employ the carbon-monoxide method in well-ventilated, outdoor areas to avoid poisoning themselves and others. So exterminators cannot use this method on rats in subway stations, in sewers, or even too close to inhabited buildings.

Munshi-South said that the main challenge is the mountains of garbage that New York City produces, and an inability to keep rats from accessing it.

While there's no one good solution for it, Munshi-South said a citywide initiative to contain garbage — such as providing large rat-resistant containers that businesses could throw their trash in rather than letting it pile up on the street — could work. But he said that could be too controversial, and that a lot of people don't want to give up street-parking spots for garbage containers.

He also said the city needs a cultural shift. "There's so much takeout food in New York City and people just eat on the street and just leave it, put it in overflowing garbage cans, throw it on the subway tracks," he said. "It's really a cultural issue. It doesn't have to be that way."

Ultimately, it will take a combination of strategies to eradicate New York City's rats, and there's no silver bullet, no matter how effective one method might seem.

"No one thing is going to change the situation," Munshi-South said. "They may be useful tools, but they're not a solution overall."