MIDDLEBORO — The operator of local Dunkin’ Donuts franchises has been cited for violating federal child labor laws at 12 locations, including three in Middleboro, following an investigation by the U.S. Department of Labor.

Fernando Sardinha was cited for allowing 21 employees ages 14 and 15 to work more hours than federal law allows, according to the U.S. Department of Labor’s Wage and Hour Division.

Employers at his 447 Wareham St. location in Middleboro were cited for permitting three employees younger than 16 to operate an oven used to make sandwiches, which the agency described as a hazardous occupation for young workers. 

At the same location, the investigation also found youths working more than 8 hours per day and more than 40 hours per week during a non-school week, the agency reported. 

Other Middleboro violations were at the 3 East Grove St. location, where two employees were alleged to have worked more than three hours on a school day and 47 Harding St., where one employee worked more than three hours on a school day, the agency reported.

 The division assessed Sardinha and his businesses with $20,121 in civil penalties to resolve their violations of the Fair Labor Standards Act’s child labor provisions. As part of the settlement, the employers agreed to a number of conditions, including not employing minors under 14; creating an internal policy to comply with child labor hours standards; and appointing a child labor compliance officer. 

Federal labor law prohibits the employment of workers under the age of 14 in non-agricultural settings. At ages 14 and 15, workers must be employed outside of school hours and cannot work more than three hours on a school day, including Friday; more than 18 hours a week when school is in session; more than eight hours per day when school is not in session; more than 40 hours a week when school is not in session; and before 7 a.m. or after 7 p.m. on an day except from June 1 through Labor Day, when nighttime hours are extended to 9 p.m. 

Sardinha also owns franchises in Assonet, Berkley, Hanover, Marion, Mattapoisett and Weymouth.