Z133 Publication Update

Publication of the next revision of the Z133 is now projected by mid-2026. This timeline is a result of the audit process with ANSI that must be completed before the new standard can be approved and ISA can be reaccredited. We apologize for the delay; this timeline is not within ISA’s control and we are not able to provide a more precise timeline at the moment.

2025 Z133 Safety Standard Advance Request for Unapproved Copy

Thank you for your patience as we navigate through the ANSI approval process of the Z133 standard. Prior to approval, we’re providing an option to receive an advanced UNAPPROVED copy of the DRAFT 2025 Z133 Safety Standard for those who wish to prepare their education and training programs. To access this digital copy, please click here to complete the request form.

The ANSI Z133-2017 remains the standard of reference for OSHA and the standard that arboricultural operations in the United States are required to comply with. The draft revision is provided for preparation purposes only and not intended to replace the ANSI Z133-2017 until it is approved and published.

Z133 Meeting UpdateS

As we continue to make steps towards the revised standard approval process, the second of two meetings to address required procedural corrections is scheduled for Tuesday, September 9, 2025, 9:00AM-11:00AM CDT.

If your contact information has changed, please complete this form.

If you have any questions please contact Chericka Ashley at Z133@isa-arbor.com or call 678-367-0981 x226.

What is the Z133?

This is an American National Standards Institute (ANSI) accredited standard which contains arboriculture safety requirements for pruning, repairing, maintaining, and removing trees; cutting brush; and for using equipment in such operations.

Who creates it?

The standard is a collaborative effort of industry experts and representatives. The development of the standard is done under a five year revision cycle. Contributors consist of an Accredited Standards Committee (Voting Members), Task Chairs/Groups and interested parties. The revision cycle also includes a public review period.

For a listing of current developers visit our Membership page.

The International Society of Arboriculture (ISA) acts as Secretariat for ASC Z133. If you would like to contact ISA about a Z related question, please email us at Z133@isa-arbor.com.

Who needs it?

Employers engaged in pruning, repairing, maintaining, and removing trees; cutting brush; or performing pest or soil management related to tree care who hire one or more persons to perform such work. Other stakeholders would include contractors of such services and manufacturers and suppliers of equipment used in the provision of those services.

When is the Z133 revised?

The Z133 is revised on a five-year cycle, though the exact time can vary. The current edition is the Z133-2017. We are going through audit, reaccreditation, and approval steps with ANSI before the Z133-2025 can be published, but the 2025 cycle committee work is completed. A new committee is in place to begin the process for the 2030 revision.

Want to get a sense of how far we have come over the years? Check out the Evolution of the Z133!

DIGITAL Z

The ASC Z133 - 2017 is available in digital format! Now you can access your copy of the Z133 right from your phone or tablet.

To get your digital copy today, visit the ISA store.

Compatible with iOS and Android.

Licensing the Digital Z133 Safety Standard

You can license the Z133 Safety Standard for your company. Use it for training purposes and more.

Contact ISA for more information at Z133@isa-arbor.com

Spanish Z Now Available!

The ASC Z133-2017 safety standard is now available in Spanish. Thank you to all the hard working volunteers who helped us complete this translation!

Purchase copies in the ISA store.

Interpretations

If you need assistance with an interpretation of a specific section of the Z133 Safety Standard, please click here to complete an Interpretation Request Form. Submit the completed form to Z133@isa-arbor.com

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