Twelve hotel chains were named and accused of knowing and ignoring warning signs that women and children were sold as sex slaves on their premises, according to the filing, a consolidation of 13 existing cases, in U.S. federal court in Columbus, Ohio.

The filing marked the first time the hotel industry – which has long been accused of serving as a breeding ground for sexual exploitation of women and children – faced action as a group.

The case drew together 13 separate actions that had been filed in Ohio, Massachusetts, Georgia, Texas and New York.

Among those named in the 13 cases were Hilton Worldwide Holdings Inc., Red Roof Inn, Intercontinental Hotels & Resorts, Best Western Hotels & Resorts and Wyndham Hotels and Resorts Inc.

Representatives of the hotel groups did not immediately respond to requests for comment...

The hotels “derived profit” and “benefited financially” by “providing a marketplace for sex trafficking,” the case said, citing “industry-wide failures.”

“Such corporate malfeasance has led to a burgeoning of sex trafficking occurring in … hotels that has reached the level of a nationwide epidemic,” it said.

An estimated 400,000 people are believed trapped in modern slavery in the United States, from forced labor to sex trafficking, according to the Global Slavery Index, published by the human rights group Walk Free Foundation...

“The entire barrel has a problem … For years the hospitality industry has known that sex trafficking and especially child sex trafficking has occurred on their properties and yet it continues to happen.”

One of the women in the complaint said she was held captive at age 26 at various locations of Wyndham Hotels for six weeks in 2012.