A new ad from Sen. Bob Casey (D-Pa.) attempts to highlight allegations of a toxic work environment at the hedge fund formerly run by Republican Senate candidate Dave McCormick.

The ad specifically cites “The Fund,” the 2023 book from New York Times finance reporter Rob Copeland, which says McCormick allegedly told a former employee to remain silent about her claims of sexual misconduct or face litigation.

McCormick led Bridgewater Capital from 2017 to 2022, before leaving the hedge fund to launch his first race for U.S. Senate in Pennsylvania. The firm, based in Westport, Connecticut, is known for its intense culture of “radical transparency” fostered under its founder, Ray Dalio.

Democrats have dug into McCormick’s time at Bridgewater to attack him in one of the country’s most competitive Senate races. They have pointed out that under McCormick, the fund shed jobs while accepting tax dollars and benefiting from trade policies he helped shape as a top Treasury Department official in George W. Bush’s administration.

McCormick’s spokesperson has previously downplayed reporting from “The Fund: Ray Dalio, Bridgewater Associates, and the Unraveling of a Wall Street Legend” as “retread.”

Copeland’s book reported that McCormick had been involved in silencing two women at Bridgewater who reported sexual harassment. In one case, after a former employee accused McCormick’s former co-CEO, Greg Jensen, of grabbing her bottom at a party, the Senate candidate reportedly told her, in a meeting with Dalio after she had left the company, “that they had the power to destroy her business if she didn’t toe the line.”

In another instance, McCormick allegedly told a woman who signed a non-disclosure agreement after she accused a male co-worker of cornering her in the office that she would “be in litigation for the rest of her life” if she ever violated the agreement.

Dalio has defended the culture at the firm as a key to its growth.

Casey’s campaign is highlighting that exchange and other aspects of what the campaign is framing as the “toxic” work environment it alleges McCormick helped foster at Bridgewater.

Watch the ad, called “Toxic,” here:

Casey, the Democratic incumbent, is locked in a tight and expensive race against McCormick that could determine control of the Senate in November. The Cook Political Report, a top election forecaster, recently tweaked its rating for U.S. Senate in Pennsylvania from leans Democratic to a toss-up as the presidential race there remains in a dead heat.

For that Senate contest alone, Republicans have reserved $27 million in TV ads between now until Election Day, while Democrats have $19 million reserved, according to AdImpact data.