New York's attorney general has launched an inquiry into 13 major retailers, questioning the practice of keeping workers on call for shifts on short notice and possible violations of the state requirement to pay hourly staff for at least four hours when they report for work.

Letters were sent to Gap Inc., Abercrombie & Fitch, J. Crew Group Inc., L. Brands, Burlington Coat Factory, TJX Companies, Urban Outfitters, Target Corp., Sears Holding Corp., Williams Sonoma Inc., Crocs, Ann Inc. and J.C. Penney Co. Inc. 

"We have been informed that a number of companies in New York State utilize on-call shifts and require employees to report in some manner, whether by phone, text message or email, before the designated shift in order to learn whether their services are ultimately needed on site that day," Labor Bureau Chief Terri Gerstein wrote to the retailers. "We are examining this practice."

The attorney general's office said it has received reports of more employers setting shifts the night before or even just a few hours in advance, including these 13.