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Print shows three types of mice and a brown rat, all full-length, profile views; also shows, on upper left, a "skull of Meadow mouse" and on upper right a "skull of Brown rat".
1. Jumping mouse. 2. White footed mouse. 3. Meadow mouse. 4. Brown rat. L. Prang & Co. 1874. Library of Congress Prints and Photogrpahs Division. //

The New York City Rat’s Legal History

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The following is a foreword by Senior Legal Information Specialist at the Law Library of Congress, Jennifer González, which introduces this guest post. 

Perusing the Law Library collection of United States Treaties, there are so many interesting topics. One such topic that caught my attention was the amount of multilateral treaties for the purpose of “sanitation.” Digging a bit deeper, I noticed that a lot of these had mentions of “rats” and “vermin” in the same clause as “mosquitos” and “lice.” Nations signed treaties to inform each other of “unusual mortality among rats and mice,” “plague suspicious cargo” (where rats hide on the ship), and used the word “deratization.” Interestingly, when looking at our collection of early multilateral treaties, “rats” is mentioned 87 times in the first volume (from 1776-1917) with the first mention in 1903. The second volume mentions “rats” 55 times, the third volume only four times, and it does not appear in the fourth volume. Despite the decline of international treaties in recent years, rats can still be a problem in modern cities, so Grace, an intern with the Digital Resources Division, looked at one example of a city government’s response to the rat crisis.

The following is a guest post by Grace Wipfli, an intern with the Digital Resources Division of the Law Library of Congress. She is an aspiring attorney, holding a B.A. in English rhetoric and a minor in communication studies from Florida Atlantic University.

Referred to as New York City’s “unofficial mascot,” rats have established steely residency throughout the Big Apple for decades. However, city officials are attempting to mitigate this “four-legged menace” through targeted legislation. Most recently, New York City Mayor Eric Adams signed a bill package titled the Rat Action Plan, which will be discussed in further detail below. As Mayor Adams intends to create “a cleaner and more welcoming city for New Yorkers,” the package contains four pieces of legislation amending the New York City Administrative Code. While the Rat Action Plan symbolizes a marked effort toward deterring the overpopulation of rats, New York City boasts a lengthy legislative history in dealing with these urban rodents.

City of New York / sketched and drawn on stone by C. Parsons, c. 1856. Library of Congress Prints and Photographs Division,
History of the New York City Rat

Ancestors of the New York City rat initially arrived in North America almost two and a half centuries ago aboard the ships of early voyagers. The rats survived and thrived amidst seafaring environments, often managing “better than men” during ocean passages. Commonly referred to as old-world rats, a high level of adaptability allowed for mass migration across various boats, trains, and trucks carrying freight. While the black rat (Rattus rattus) traveled to North America alongside the Spanish military in the sixteenth century, the Norway rat (Rattus norvegicus) stowed away with traders and colonists a century later. In 1938, New York City sailor William Wood attributed the overwhelming presence of rats to “man and his ships,” in which these rodents “spread and multiplied on every continent.” Further, Wood attested to the troublesome nature of the “bold” and “ferocious” rats when claiming “all known methods” of exterminating them seemed insufficient.

In 2015, the National Association of County and City Health Officials reported New York City as having “one of the largest rat populations in the United States.” Likewise, Research Scientist and Urban Rodentologist Bobby Corrigan attributes this aggregation to “New York being one of America’s oldest seaport cities and the most densely populated city in the U.S.” Perhaps, then, it is unsurprising that the most common New York Species, the Norway rat, populates near human establishments and residences. Thus, Norway rats likely multiplied partly due to the city’s “uniquely ideal urban habitat.”

Overall, Corrigan suggests that such an ideal combination of environmental conditions “allow the opportunistic brown rat to proliferate, spread, and repeatedly rebound from extermination campaigns that have been directed at it for over 200 years.”

A colored image of the species Rattus norvegicus (Norway Rat) in a glass/plastic habitat enclosure.
Norway Rat. 2011. Meghan Murphy. Smithsonian’s National Zoo & Conservation Biology Institute.

Typically found in urban environments, underground burrows, crawl spaces, and basements, Norway rats can pose serious health threats to the citizens of New York City. Aside from the nuisance of gnawing and property damage, city rats contaminate food and spread disease. For instance, rats are the primary source of bacteria causing leptospirosis in New York City, a harmful disease that affects both humans and animals. Additionally, scientists in a 2014 Columbia University study identified numerous bacterial pathogens in New York City rats. These infections included E. coli, Salmonella, C. difficile, and Seoul hantavirus, which causes low blood pressure, acute shock, and kidney failure.

History of New York City’s Legislative History

While the Rat Action Plan has the potential to aid in these concerns, New York City’s legislative history reveals a prolonged mitigation effort. In 1964, the administrative code documented roughly 43,000 residence buildings in “such poor structural condition as to readily provide rat harborages.” Confirming these issues were “widespread throughout the entire City,” the Board of Health deemed rat infestations dangerous to life and health. In resolution, the Board of Health declared that all persons (according to subdivisions (a) or (b) of section 17-148) are required to abate rats and conditions caused by their harborage. Similarly, in 1999, multiple city council members requested hearings to discuss the overwhelming rat population, citing, “changes in the city’s rat-fighting budget and its garbage disposal policies have inadvertently given rats aid and comfort.” One year later, the Committee on Housing and Buildings attempted to pass a bill similar to the recent Intro 442-A of the Rat Action Plan. Both bills proposed abating rats as a requirement for foundation permits; however, the 2000 predecessor was eventually filed.

A black and white image of a rat catcher holding a medium-sized rat with a metal tool.
Rat catcher at work. Photo by Bain News Service. Date unknown. Library of Congress Prints and Photographs Division //

As for mayoral involvement, then-Mayor Rudy Giuliani pioneered the Rodent Extermination Task Force in July 2000. Under this initiative, the city’s rodent-control budget had risen to $13 million in 2000 from $5.5 million in 1997. In response, the city council suggested “the best way to conquer the rats is to create a new umbrella agency–a permanent government body that will outlive mayoral task forces and short lived rat emergencies.” Three months later, the Select Committee on Pest Control held a hearing to address private sector responses to the rat epidemic. The committee report claimed the recent efforts in reducing rat populations would only be successful once “the appropriate balance is struck between community and governmental participation” (Oversight – Private Sector Responses to the Rat Epidemic Committee Report, page 1). All within the same year, the Select Committee conducted six more hearings regarding New York City’s rampant rat infestation. According to the same report, residents attended from all boroughs and testified concerning the rat problems in their neighborhoods. As the rat population exploded, then-Mayor Michael Bloomberg expanded on Giuliani’s initiative, renaming it the Abatement Task Force.

Yet, tensions continued to rise as a 2003 resolution called for the expansion of abatement programs not only to specific neighborhoods but the entire city of New York. Additionally, a 2004 resolution requested the Department of Health declare the Bronx a “rat-infested disaster area” and hold hearings on the results of the mayor’s 2003 special rat initiative. Finally, in 2017, then-Mayor Bill de Blasio significantly boosted rat control efforts by launching the Neighborhood Rat Reduction Initiative. Under Mayor de Blasio, the New York City government pledged $32 million, aiming to “reduce rat activity by up to 70 percent in the targeted zones by minimizing food sources and available habitats.”

Current Legislation

Nowadays, many New York agencies collaborate in mitigation efforts. While the Department of Health and Mental Hygiene (DOHMH) chiefly enforces legislation, the City Departments of Buildings, Housing Preservation & Development, and Sanitation are also authorized to do so. According to Article 151, Section 2 of the health code, property owners are legally required to prevent and manage rats. In some instances, when the DOHMH determines conditions conducive to pests, a written management plan is required. Further, according to Title 17, Section 17-133.1 of the administrative code, property owners who fail to eradicate rodents “shall be liable to pay a civil penalty of not less than three hundred dollars for the first violation.”

Since last year, Mayor Adams and the New York City Council have been retackling the rat problem. On November 18, 2022, Mayor Adams signed the Rat Action Plan into law, stating, “This legislation doubles down on our efforts and is another important step to put a dent in our rodent population. Rat-free streets are vital to vibrant neighborhoods and our city’s economic recovery, and I thank the City Council for their partnership in keeping our city squeaky clean.” The four bills, now enacted, establish the following:

i. Intro 414-A: Rat mitigation progress in rat mitigation zones.

The Committee on Sanitation and Solid Waste Management introduced bill 414-A on May 19, 2022. The Intro proposed an amendment to the New York City Administrative Code by adding section 17-133.3. Chapter 1 (Department of Health and Mental Hygiene) of title 17 (Health). Enacted on November 18, 2022, section 17-133.3 requires the DOHMH to issue an annual report on the success of rat mitigation measures. Additionally, the information must outline the metrics used to measure efficacy, describe improvement progress, and explain the creation or elimination of mitigation zones.

ii. Intro 442-A: Abating rodents as a requirement for the issuance of certain construction permits.

The Committee on Sanitation and Solid Waste Management introduced bill 442-A on May 26, 2022. The Intro proposed an amendment to the New York City Administrative Code by adding section 28-105.2.3 to Article 105 (Permits) of Chapter 1 (Administration) of title 28 (New York City Construction Codes). Enacted on November 18, 2022, section 28-105.2.3 requires those seeking construction permits to certify that their premises have been effectively treated for rodent extermination by a licensed exterminator.

iii. Intro 459-A: Rat mitigation zones.

The Committee on Sanitation and Solid Waste Management introduced bill 459-A on June 2, 2022. Enacted on November 18, 2022, this Intro proposed two amendments to the New York City Administrative Code. The first amendment to section 1, Subdivision c of section 16-120 (Receptacles for the removal of waste material) now allows the Department of Sanitation to determine when buildings must set out their garbage and recycling for collection. The second amendment to Chapter 1 (Department of Health and Mental Hygiene) of title 17 (Health) added a new section 17-133.2, requiring the DOHMH to designate rat mitigation zones by April 1, 2023.

iv. Intro 460-A: Receptacles in a building or dwelling that has a high concentration of rodent infestation.

The Committee on Sanitation and Solid Waste Management introduced bill 460-A on June 2, 2022. The Intro proposed an amendment to section 1, Subdivision a of section 16-120 (Receptacles for the removal of waste material) of Chapter 1 (Department of Sanitation) of title 16 (Sanitation). Enacted on November 18, 2022, this amendment requires buildings that have received two or more rodent-specific violations to utilize approved rodent-resistant containers for at least two years.

Beyond these four pieces of legislation, Mayor Adams appointed Kathleen Corradi as New York City’s first “Rat Czar” on April 12, 2023. On the responsibilities of this new role, Mayor Adams remarked, “[b]eginning with this $3.5 million investment toward rodent mitigation in Harlem, Kathy will take the lead on our multi-agency effort to test new mitigation techniques, expand outreach and education efforts, and increase maintenance and remediation work. The rats are going to hate Kathy, but we’re excited to have her leading this important effort.” Just as the Department of Sanitation Commissioner Jessica Tisch states, “the rats don’t run this city,” many New Yorkers have voiced their individual opinions. To read about New Yorker attitudes regarding rat mitigation, visit:

If you would like to learn more about New York City’s rat mitigation efforts, you may wish to consult these selected sources:

  1. Interactive Rat Reporting Map:
  2. Rat Prevention Training (Rat Academy):
  3. Preventing Rats on Your Property (A Guide for Property Owners and Tenants):
  4. Rat Complaint Hotline/NYC 311:

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