Child Labor in the US: 
The Fair Labor Standards Act (FLSA, passed in 1938)

 "The FLSA regulates child labor by (a) setting minimum ages for jobs that have been determined to be particularly hazardous, (b) setting minimum ages for all other jobs (that is, jobs that are not considered particularly hazardous), and (c) limiting the hours that children are permitted to work.  There are also exceptions to some of these requirements." ~ Source


There are 17 Hazardous Orders pertaining to all industries (other than agriculture) that forbid children under age 18 from doing any of the following jobs.

1. Manufacturing or storing explosives.
2. Driving a motor vehicle and being an outside helper on a motor vehicle.
3. Coal mining.
4. Logging and sawmilling.
5. Operating power-driven wood-working machines.
6. Exposure to radioactive substances and to ionizing radiations.
7. Operating power-driven hoisting equipment.
8. Operating power-driven metal-forming, punching, and shearing machines.
9. Mining, other than coal mining.
10. Operating power-driven meat-processing machines, and slaughtering, meat packing or processing, and rendering.
11. Operating power-driven bakery machines.
12. Operating power-driven paper-products machines, scrap paper balers, and paper box compactors (except that 16- and 17-year-olds can load – but not operate or unload – scrap paper balers and paper box compactors that meet certain safety requirements).
13. Manufacturing brick, tile, and related products.
14. Operating power-driven circular saws, band saws, and guillotine shears.
15. Wrecking, demolition, and shipbreaking operations.
16. Working in roofing operations (including any work on or in close proximity to roofs, such as installing or repairing gutters and cable and satellite dishes on roofs).
17. Working in certain excavation operations.

There are exceptions to some of these Hazardous Orders that permit children younger than age 16 in agriculture, and children younger than age 18 in all other industries, to do particularly hazardous work if they are apprentices or student-learners.
-("Child Labor in the U.S." Stopchildlabor)