In 1938 the US government passed the Fair Labor Standards Act mandating a forty hour work week, establishing a minimum wage, and prohibiting child labor. Because of legislation like this, government is often credited for making the American work environment safer and more fair. Yet, as Antony Davies and James Harrigan demonstrate with historical data, market forces were already making things easier on the American worker long before the FLSA.
See page 170 for average weekly work hours.
See page 134 for child labor rates.