The OSHA maximum step height for standard fixed stairs in general industry workplaces is 9.5 inches, measured under 29 CFR 1910.25(c)(2). Steeper stair types, mobile ladder stands, and fixed ladders each carry their own numbers, and a serious citation for getting any of them wrong reaches $16,550 per violation in 2025.
The 9.5-Inch Cap on Standard Fixed Stairs
Standard stairs, the type found in most factories, warehouses, and office buildings, must sit at an angle between 30 and 50 degrees from horizontal. The riser cannot exceed 9.5 inches, and the tread must be at least 9.5 inches deep.1Occupational Safety and Health Administration. 1910.25 – Stairways There is no federal minimum riser height for standard stairs; the angle and tread-depth rules do that work indirectly.
Stairs installed before January 17, 2017, have a choice. They can meet the current dimensions, or they can match the older Table D-1 dimensions that were in effect when they were built.2eCFR. 29 CFR 1910.25 – Stairways Anything built or substantially modified after that date has to meet the current standard.
Steeper Stair Types Have Different Limits
If a standard staircase won’t physically fit, OSHA allows two steeper types, and the 9.5-inch cap does not apply to either one.
Ship Stairs
Ship stairs, sometimes called ship ladders, are installed at 50 to 70 degrees from horizontal. The vertical rise between tread surfaces must fall between 6.5 and 12 inches. Treads only need a minimum depth of 4 inches and must be at least 18 inches wide, and the risers have to be open so you can see through each step.2eCFR. 29 CFR 1910.25 – Stairways
Alternating Tread-Type Stairs
Alternating tread-type stairs use a staggered, paddle-shaped tread pattern and sit at the same 50-to-70-degree pitch as ship stairs. OSHA does not set a maximum riser height for these stairs. Instead, 29 CFR 1910.25(f) controls the geometry through tread dimensions and handrail spacing:2eCFR. 29 CFR 1910.25 – Stairways
- Minimum tread depth of 8.5 inches
- Minimum tread width of 7 inches at the leading edge
- Handrail spacing of 17 to 24 inches
- Open risers required if the tread depth is less than 9.5 inches
If you are inspecting one of these stairs, focus on tread dimensions and slope. A riser-height number does not exist in the regulation.
Mobile Ladder Stands: 10-Inch Maximum
Mobile ladder stands, the rolling platforms used in warehouses and around CNC machines, follow a tighter rule than fixed stairs. Under 29 CFR 1910.23(e)(2)(i), steps must be uniformly spaced with a rise of no more than 10 inches.3Occupational Safety and Health Administration. Requirements of Mobile Ladder Stand Platforms Used to Access CNC Machines There is no specified minimum, only the 10-inch ceiling and the uniformity requirement.
Fixed and Portable Ladders: Rung Spacing
Ladders sit under a separate regulation, 29 CFR 1910.23. Rungs, cleats, and steps must be spaced between 10 and 14 inches apart, measured between centerlines. Two narrow exceptions allow wider spacing: elevator shaft ladders can run 6 to 16.5 inches between rungs along the side rails, and telecommunication tower ladders can go up to 18 inches. Outside those exceptions, spacing must be uniform for the full length of the ladder.4UpCodes. 29 CFR 1910.23 – General Requirements for All Ladders
Rungs and steps must also provide a minimum clear width of 16 inches. That is the usable stepping surface, not the overall ladder width, so hardware or frame components that intrude on the rung can trigger a violation even when the ladder itself is wider.
Uniformity Applies to Every Stair Type
Riser heights and tread depths must be uniform throughout each flight of stairs, between landings. That rule sits in 29 CFR 1910.25(b)(3) for general industry stairways.1Occupational Safety and Health Administration. 1910.25 – Stairways The general industry standard does not attach a numeric tolerance. The construction standard at 29 CFR 1926.1052(a)(3) does: variation cannot exceed one-quarter inch between the tallest and shortest riser, or the deepest and shallowest tread, in any stairway system.5Occupational Safety and Health Administration. 1926.1052 – Stairways A stair that meets the 9.5-inch maximum on average can still be cited if individual steps vary noticeably from each other.
Penalties for Step-Height Violations
Walking-working surface citations, including riser height and step spacing, are among the most frequently issued OSHA violations. The 2025 penalty amounts:6Occupational Safety and Health Administration. 2025 Annual Adjustments to OSHA Civil Penalties
- Serious violation: $1,221 minimum, $16,550 maximum per violation
- Other-than-serious violation: up to $16,550 per violation, no mandatory minimum
- Willful or repeated violation: $11,823 to $165,514 per violation
- Failure to abate: up to $16,550 per day past the correction deadline
These amounts adjust each year for inflation.7Occupational Safety and Health Administration. OSHA Penalties The abatement requirement is often the more expensive piece: once a citation is issued, the employer has to fix the hazard by the stated deadline or the daily penalties start running.