The union representing more than 100 laid-off employees of the Signature Room and Signature Lounge filed a lawsuit Monday alleging employees weren’t given proper notice of the layoffs.

The Signature Room at the 95th and the Signature Lounge at the 96th, iconic venues near the top of the Magnificent Mile skyscraper formerly known as the John Hancock Center, shuttered abruptly last Thursday.

The lawsuit, filed in federal court in Chicago by hospitality union Unite Here Local 1, alleges about 130 workers it represented there were laid off in violation of the Worker Adjustment and Retraining Notification Act, which requires certain large employers to provide written notice of certain business closures or mass layoffs at least 60 days in advance.

The Signature Room workers unionized with Unite Here included cooks, servers, bartenders, barbacks, concierges and other staff, according to the union, which said a third of the laid off employees had worked there for 15 years or more and some had celebrated 30-year tenures this summer.

The lawsuit alleges workers found out about the venue closures via email Thursday morning. The filing seeks backpay and benefits for the laid-off staff.

“Defendant failed to pay their former employees represented by Local 1 their respective wages, salary, commissions, bonuses, health and life insurance premiums, accrued holiday pay and accrued vacation for 60 days following their respective terminations, and failed to provide employee benefits including health insurance and pension benefits, for 60 days from and after the dates of their respective terminations,” the lawsuit alleges.

“This restaurant is iconic not just for its views but because of the hardworking staff, many of whom dedicated decades of their lives to this place,” Unite Here Local 1 President Karen Kent said in a statement. “For the Signature Room operator to jettison these workers overnight is both immoral and illegal.”

A message posted to the restaurant’s social media pages Thursday cited the COVID-19 pandemic and subsequent “severe economic hardship” as reasons for its permanent closure.

“The challenges have been greater than we anticipated. These factors, beyond our control, have left us with no choice but to close our doors,” the post read.

Efforts to reach the company’s management for comment Monday were unsuccessful.

Signature Room owners Rick Roman and Nick Pyknis, who had run the Signature Room since 1993, are both heads of Infusion Management Group. The group was awarded a $2 million federal Paycheck Protection Program in 2021 that was forgiven at the beginning of last year. It had first been awarded a $2.4 million PPP loan in 2020 that was partially forgiven the following year.