Chicago officials are weighing legal action against Barre Seid, the 94-year-old industrialist behind the largest known political advocacy donation in U.S. history, over claims that workers he hires to scatter nuts in Lincoln Park are fueling a rat infestation. Ald. Timmy Knudsen told Axios he is pushing the Chicago Park District to sue Seid for damage to the park, while Park District officials told the publication they are still weighing their options. In an Aug. 25 letter to Seid, Knudsen called the matter a final warning and said city staff had received photos and video documenting Seid or his staff putting out food daily for squirrels and other wildlife, according to WGN. The letter said the feeding created a public health hazard because it drew in not only squirrels but also pigeons and rats. Knudsen cited repeated violations of a city code provision barring the buildup of garbage or food that could feed or shelter rats, according to Block Club Chicago, and gave Seid 15 days to stop.While the city has issued citations, it allegedly did little to end the feeding of Chicago’s wildlife. The letter states that Streets and Sanitation has inspected the property multiple times over several years and issued multiple warnings and citations, and that the violations continued despite the fines being paid. Seid paid all fines and tickets without contesting them, Axios reported.“Typically, when you ticket somebody, it stops their bad behavior,” Knudsen told WGN. He said the feeding has increased since the city began ticketing. Neither Knudsen nor Seid responded to Fortune’s requests for comment.Shells from Brazil nuts, hazelnuts, peanuts and walnuts were seen at the base of trees near rat burrows in the park, Axios reported. Knudsen told the publication the burrows have grown where the nuts are left, and that Green City Market vendors have seen rats while setting up. Meanwhile, city documents say taxpayers could end up paying for repairs.According to neighbors and Knudsen, Seid and his wife, Barbara, have hired people for years to carry bags of nuts through the neighborhood and the park to feed squirrels, Block Club reported. Knudsen said the workers have been distributing nuts in the park, two or three blocks from the Seids’ home, since early spring.Chicago has ranked first on Orkin’s list of America’s rattiest cities every year since the list began, ten straight years as of 2024. Who is Barre Seid?Seid made his fortune as the owner of Tripp Lite, a Chicago maker of surge protectors and power equipment. ProPublica reported that he transferred the company to a dark money group run by conservative legal activist Leonard Leo, created in April 2020. It was then sold to Eaton in March 2021 for $1.65 billion, according to the company’s SEC filing, and thanks to that structure, tax experts told ProPublica Seid was able to avoid as much as $400 million in taxes.As Tripp Lite grew, Seid wrote checks to the Republican National Committee, ProPublica reported, and a longtime adviser described him as the Heartland Institute’s major patron, a Chicago-area think tank that disputes mainstream climate science. Tax records obtained by ProPublica show at least $775 million in donations to nonprofits between 1996 and 2018, almost all of it anonymous.In one email obtained by ProPublica and The Lever, Seid described himself as prone to “anonymity paranoia.” He sometimes used a fake name, Ebert or Elbert Howell, which Tripp Lite staff gave to salesmen and business registries as the CEO’s name, according to his testimony in a federal lawsuit. Chicago has ranked first on Orkin’s list of America’s rattiest cities every year since the list began, ten straight years as of 2024. This story was originally featured on Fortune.com