(Reuters) — U.S. regulators have asked 15 retailers, including Aeropostale Inc., American Eagle Outfitters Inc., Coach Inc. and Walt Disney Co., to discuss whether they use a controversial practice of canceling shifts of hourly workers with almost no notice.

The attorneys general of eight U.S. states and Washington sent letters seeking information about “on-call” scheduling, where workers dial their employers an hour or two before their scheduled shifts to learn whether they should show up.

Such scheduling can help retailers save money by avoiding overstaffing during slow periods, while ensuring they have enough staffing when stores are crowded.

But according to the letters, workers can be harmed by “unpredictable” work schedules because they can increase stress, strain family life, and make it harder to arrange child care or pursue an education.

The letters also say on-call scheduling may violate state labor laws requiring workers to be paid for at least part of a day even if they are told to stay home, and is not a “business necessity” given that some chains have abandoned the practice.

Other retailers receiving the letters are BCBG Max Azria, Carter’s Inc., Canada’s DavidsTea Inc., Forever 21 Inc., Ascena Retail Group Inc.’s Justice, Pacific Sunwear of California Inc., Payless ShoeSource, Tillys Inc., Fast Retailing Co’s Uniqlo, VF Corp’s Van’s and Zumiez Inc.

The letters seek such information as payroll records, store work schedules, employee handbooks, and the degree to which store managers have autonomy to decide who works and when.

In April 2015, New York Attorney General Eric Schneiderman sent letters to 13 retailers asking about their on-call scheduling practices.

He was joined in the latest requests by the attorneys general of California, Connecticut, the District of Columbia, Illinois, Maryland, Massachusetts, Minnesota and Rhode Island.

Retailers that have ended on-call scheduling since the original letters were sent include Abercrombie & Fitch Inc., L Brands Inc.’s Bath & Body Works and Victoria’s Secret, Gap Inc., J Crew Group Inc., Pier 1 Imports Inc. and Urban Outfitters Inc.

Spokeswomen for Coach and Payless said their companies do not use on-call scheduling. A spokesman for Zumiez said that company will cooperate. A spokesman for Carter’s said that company is reviewing its letter. Other retailers receiving the new letters did not immediately respond to requests for comment.