A study has found that many teenage workers in the retail and service industries say they work long hours and use dangerous equipment despite federal child labor laws prohibiting these practices.

The study, conducted by researchers from the University of North Carolina at Chapel Hill, found that 52 percent of males under 18 and 43 percent of females under 18 reported using dangerous equipment (such a box crushers and dough mixers) or serving and selling alcohol where it is consumed, indicating violations of federal law.

The study also found that 37 percent of workers under the age of 16 reported working after 7 p.m. on a school night. Federal law limits the hours children aged 14 and 15 may work to 7 a.m. to 7 p.m. on any day, except from June 1 through Labor Day when they may work from 7 a.m. to 9 p.m.

"Though there are benefits to work, not enough attention has been paid to safety," says Carol Runyan, director of UNC's Injury Prevention Research Center (IPRC) and an author of the study. "Federal and state child labor laws are designed to restrict the working environments, tasks and hours that teens work. However, the data we collected suggest there are gaps in how well businesses are complying."

The study also found that about one-third of young workers reported receiving no safety training.

The study is published in March 1 issue of the journal Pediatrics. For the study, the researchers conducted telephone interviews with working adolescents aged 14 to 18.