The US Court of Appeals for the Seventh Circuit on Thursday repealed a lower court’s order certifying a class action lawsuit filed by nearly 2,000 female employees alleging an “epidemic” of sexual harassment while working at the Cook County Jail in Cook County, Illinois.

In a 38-page opinion, the three-judge panel held that the lower court “abused its discretion in certifying the class” and that the class cannot stand “because it comprises class members with materially different working environments whose claims require separate, individual analyses.”

The 10 named plaintiffs in the case are women who work at the jail complex—one of the largest single-site jails in the US. Spaning eight city blocks, the campus consists of 36 separate buildings and houses approximately 100,000 inmates annually. The women brought suit against the jail and the Cook County Sheriff’s Office, alleging they “endured frequent and extreme sexual harassment by male inmates,” including exhibitionist masturbation, sexual epithets and threats, and sexual violence. They further allege they have complained about the harassment to no avail and that the jail ignored their complaints and took no preventative measures to prevent the harassment.

In 2017 the women, on behalf of themselves and other similarly-situated women working in the jail complex, sued for “permitting a hostile work environment in violation of Title VII of the Civil Rights Act of 1964.” The US District Court for the Northern District of Illinois originally certified the class in August 2019, but narrowed the class.

The Sherrif’s Office and the jail appealed the certification that following November. They argued that the lower court erroneously accepted “ambient harassment,” which they defined as a theory “that sexual harassment of some individuals can be so severe that it invades an entire workplace, causing individuals who have not directly suffered harassment to nonetheless become atmospheric victims with their own actionable claims.”

The appellate court agreed. “[A]mbient harassment does not unite the modified class because it is no longer a central issue in the case and the plaintiffs have not shown that it manifests in the same way across different parts of the jail complex,” wrote circuit judge Amy St. Eve. “The significant variation in harassment levels across different parts of the jail complex renders certain class members’ work environments materially different from those of others.”