Chicago officials are considering legal action against Barre Seid, the 94-year-old industrialist behind the largest known political advocacy donation in U.S. history, over allegations that workers he hires to scatter nuts through Lincoln Park have fueled a rat infestation.

Alderman Timmy Knudsen is pressing the Chicago Park District, the city agency that runs Lincoln Park, to sue Seid over damage to the park, according to Axios. Park District officials told the outlet they are still evaluating their options, leaving open whether a conflict that has so far produced warnings, citations, and paid fines will move into the courts.

In an Aug. 25 letter to Seid, Knudsen described the matter as a final warning, writing that city staff had received photos and video showing Seid or his staff placing food out daily for squirrels and other wildlife, according to WGN. The letter said the feeding posed a public health hazard because it attracted not only squirrels but also pigeons and rats. Citing repeated violations of a city code provision that prohibits the accumulation of garbage or food capable of feeding or sheltering rats, Knudsen gave Seid 15 days to stop, according to Block Club Chicago.

City citations, however, have allegedly done little to end the feeding. The letter states that Streets and Sanitation has inspected the property repeatedly over several years, issuing multiple warnings and citations, and that the violations continued even after the fines were paid. Axios reported that Seid paid every fine and ticket without contesting them.

"Typically, when you ticket somebody, it stops their bad behavior," Knudsen told WGN. He said the feeding has intensified since the city began issuing tickets. Neither Knudsen nor Seid responded to Fortune's requests for comment.

Shells from Brazil nuts, hazelnuts, peanuts, and walnuts have been spotted at the base of trees near rat burrows in the park, per Axios. Knudsen said the burrows have expanded wherever the nuts are left, and vendors at Green City Market have encountered rats while setting up. City documents indicate taxpayers could end up covering the cost of repairs. For a city that has topped Orkin's list of America's rattiest cities every year since the ranking began — 10 consecutive years as of 2024 — the dispute adds an unusual chapter to Chicago's long-running rat problem.

According to neighbors and Knudsen, Seid and his wife, Barbara, have for years hired people to carry bags of nuts through the neighborhood and into the park to feed squirrels, Block Club reported. Knudsen said the workers have been distributing nuts in the park, located two or three blocks from the Seids' home, since early spring.

Who Is Barre Seid?

Seid built his fortune as the owner of Tripp Lite, a Chicago manufacturer of surge protectors and power equipment. According to ProPublica, he transferred the company to a dark-money group run by conservative legal activist Leonard Leo that was created in April 2020. The company was then sold to Eaton in March 2021 for $165 billion, according to the company's SEC filing, and tax experts told ProPublica the structure allowed Seid 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 major patron of the Heartland Institute, 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, nearly all of it anonymous.

In one email obtained by ProPublica and The Lever, Seid described himself as prone to "anonymity paranoia." He occasionally used the fake name Ebert or Elbert Howell, which Tripp Lite staff provided to salesmen and business registries as the CEO's name, according to his testimony in a federal lawsuit.

This story was originally featured on Fortune.com.