| 3319 | Hub, wooden, manufacturing | |
| 3822 | Huller, cottonseed and clover, manufacturing | |
| 9340 | Humane society | |
| 3851 | Humidity gauge manufacturing | |
| 3851 | Humidity indicator manufacturing | |
| 3220 | Hunting coat and vest cutting and sewing | |
| 3903 | Hunting equipment, excluding firearms, manufacturing | |
| 1130 | Hunting for commercial purposes, not connected with sport | |
| 9599 | Hunting guide service | |
| 1120 | Husbandry services, animal, other than veterinary | |
| 3692 | Hydrated line manufacturing | |
| 3692 | Hydraulic cement manufacturing | |
| 3812 | Hydraulic chair, barber and beauty shop, manufacturing | |
| 3829 | Hydraulic jack manufacturing | |
| 3823 | Hydraulic or pneumatic riveter manufacturing | |
| 3823 | Hydraulic press manufacturing | |
| 3511 | Hydrocarbon gas manufacturing | |
| 3511 | Hydrochloric acid manufacturing | |
| 5000 | Hydroelectric plant construction | |
| 4101 | Hydroelectric power plant | |
| 3511 | Hydrofluoric acid manufacturing | |
| 3841 | Hydrofoil ship, manufacturing | |
| 3511 | Hydrogen manufacturing | |
| 3511 | Hydrogen peroxide manufacturing | |
| 3511 | Hydrogen sulphide manufacturing | |
| 3420 | Hydrographic chart printing | |
| 8324 | Hydrographic survey service | |
| 3851 | Hydrometer manufacturing | |
| 3511 | Hydrosulphite manufacturing | |
| 3511 | Hydroxide manufacturing | |
| 3851 | Hygrometer manufacturing | |
| 3420 | Hymnal printing | |
| 3511 | Hypochlorite manufacturing | |
| 3851 | Hypodermic needle manufacturing | |
| 3851 | Hypodermic syringe manufacturing | |
| 3511 | Hypophosphite manufacturing | |