The crux (lifted from the abstract) is:
…a substantial number of youth are working at least 20 hours per week when school is in session, and many reported having worked after 11 pm on a night before school. Young workers engaged in a variety of hazardous tasks, including heavy lifting, using sharp objects, working with hot equipment, or working around falling objects.This study adds to the growing body of evidence regarding the prevalence of child labour in Canada and the risks Canadian children are exposed to in the workplace.
A small subset (7.5%) of teens had suffered an injury at work that was severe enough to cause them to miss a day of school or work or require medical attention. … Although regular check-ins were common, many youth (38%) said they had worked at least part of the day without supervision. Young females were most likely to work without supervision or to work alone. (p.380)
-- Bob Barnetson