OSHA states that step ladders longer than 20 feet shall not be supplied. It defines three types of ladders:
- Type I: Industrial stepladder, 3 to 20 feet for heavy duty, such as utilities, contractors, and industrial use.
- Type II: Commercial stepladder, 3 to 12 feet for medium duty, such as painters, offices, and light industrial use.
- Type III: Household stepladder, 3 to 6 feet for light duty, such as light household use.