At a glance
- What changed
- ISA says the Z133-2026 Safety Standard has been approved by ANSI and is now available. The previous edition, published in 2017, stayed in effect until May 27, 2026.
- Who it affects
- Employers and employees in arboricultural operations who use the Z133 safety standard. ISA offers a digital copy for individual use at no charge, and a print copy for a listed retail or member price.
- What to do
- Download the digital standard from the ISA store if you use Z133 on the crew. The page does not make the standard a government license.
- Starts
On this page
The International Society of Arboriculture Z133-2026 page says the Z133-2026 Safety Standard has been approved by ANSI and is now available.
What changes
The American National Standard, Safety and Health Requirements for Arboricultural Operations, is the Z133 standard. ISA says the previous edition, published in 2017, stayed in effect until May 27, 2026. The committee drafted revisions after that year to refine the standard.
ISA offers a digital copy in English and Spanish at no charge for individual use through its store. A print copy lists at $29.95 retail or $24.95 for members. ISA says the digital file is for individual use, not for sharing or distribution.
Who it affects
Crews that already treat Z133 as the shop safety paper. ISA does not say the new edition is a government license. Do I need a license to run a tree service? still depends on the state and city.
OSHA's tree care rulemaking page still describes a separate proposed Tree Care Operations standard. That page does not say a final OSHA tree-care rule is in force.
What you still owe or still need to do
A new Z133 edition does not book a job and does not change how Angi or Thumbtack match a request. How tree companies get more jobs is the same order.
What to do now
If the crew uses Z133, get the 2026 edition from ISA. If someone treats this update as proof they can fill the board, how to compare tree-job lead sources is the checklist.
Pages we updated
The pillar guide now notes that Z133-2026 is the current safety standard and that the 2017 edition stayed in effect through May 27, 2026.
Sources
Where our facts come from
- ISA: Z133-2026 Safety Standard now availableisa-arbor.com
How this page was checked
- Licensed professional
- None. No licensed arborist or tree-care safety officer has checked this page.
Ask about the quiet week
A partner can call about incoming tree jobs. Asking is free, and the call does not hire them or book a day for your crew.