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City using dry ice to control rat population

The technique reduced the number of rat burrows at Columbus Park from 60 to two during a pilot project.

Exterminators from the pest control division of the

Exterminators from the pest control division of the Health Department stuff rat burrows with dry " Rat Ice" in Columbus Park on Monday. Photo Credit: Linda Rosier

It’s the final lullabye for some members of the city’s bustling rat population.

The city is ramping up its use of dry ice to plug rat burrows in parks. The ice fills their underground homes with carbon dioxide, suffocating the rats which often sleep during the day.

It’s quicker, more humane and environmentally friendly than traditional rodenticide, which has felled hawks who sometimes snack on the poisoned critters.

“This is one weapon in what we do to fight rats in New York City,” said Rick Simeone, director of pest control for the city’s Health Department, during a demonstration at Columbus Park in lower Manhattan. “And it completely eliminates any chance of secondary poisoning for hawks and birds of prey.”

Simeone said the city is increasing its use of dry ice because just last year the U.S. Environmental Protection Agency registered the product “Rat Ice” from Bell Laboratories, and the New York State Department of Environmental Conservation also registered it for use as a pesticide.

Before that, several cities — including New York — conducted smaller pilot projects to control the rat population with dry ice. But the EPA wanted the dry ice registered as a product before it was widely used.

It’s all part of Mayor de Blasio’s $32 million plan to reduce the city’s rat population, with a focus on the city’s high-infestation areas: Grand Concourse in the Bronx, Chinatown/East Village/Lower East Side in Manhattan and Bushwick/Bedford-Stuyvesant in Brooklyn.

Health Department officials said during the 2016 pilot project, dry ice helped slash the number of rat burrows at Columbus Park from 60 to just two. Tompkins Square Park saw a reduction of 368 burrows down to 20.

“I’ve been here 20 years and I’ve not seen a method, if it’s applied this way, that is this effective,” Simeone said.

Pest control workers must clearly define and mark rat burrow openings in order for the dry ice to be effective.

“You have to have a burrow system and an area where you identify the colony,” said Simeone. “If you apply the product correctly, you will eliminate those rats.”

Rats can have four to six litters of offspring a year, he said, especially in the warmer months.

“If you get in early like we are doing now before the winter ends, you will have less reproducing adults which should amount to less rats,” he said.

Simeone was quick to note the dry ice will not work in every scenario. The city’s efforts to use more closed trash containers in parks, and increase garbage pick ups is key to taming the rat population.

Traditional rodenticide takes longer to work, he said. And rats might pass it by if they spot a tasty scrap of pizza or some leftover lunch.

Still, the city will continue to use rat poison in some cases. But Parks Department officials said dry ice will be used in parks with rat activity that are also home to nesting raptors.

That’s good news for wildlife rehabilitators Cathy and Bobby Horvath who have treated hawks, owls and other birds after they ingested rat poison. Bobby also serves as a city firefighter.

“This is a win for wildlife in the city,” Bobby said. “Any predator that preys on rodents is a potential victim for secondary poisoning. Even domestic pets if they catch mice or rats.”

On Tuesday, the City Council’s Sanitation Committee held a hearing on a package of rat mitigation bills. Some of the proposed legislation would require some buildings to take out garbage between 4 a.m. and 6 p.m. and require businesses to clean grease from their sidewalks.

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