The American National Standard for Arboricultural Operations—Safety Requirements (commonly referred to as the Z133 standard) is a United States safety standard for use across the arboriculture industry. The current edition of the Z133 was published in 2017. Now, the projected publication of the new Z133 standard is delayed to later in 2026.   

Under Chair Dave Scharfenberger and Vice Chair Cary Shepherd’s leadership, the Z133 Committee drafted revisions to refine the standard, ensure better safety outcomes, and keep pace with industry developments. The revision process went through two public reviews and a vote by the Z133 Committee to approve the draft for publication.   

As an American National Standards Institute (ANSI) standard, the Z133 processes are required to adhere to ANSI’s Essential Requirements, which ensure openness, balance, consensus, and due process in the drafting of the standard. These processes are subject to periodic ANSI audits, and ISA was due for a special audit prior to publishing the new draft.  

In October 2024, ISA submitted the Z133 audit package to ANSI in compliance with the special audit requirement. In June 2025, ANSI completed their special audit and provided ISA with their final results.   

In this audit, ANSI reviewed all the procedural steps involved in the drafting of the current revision. This included the meeting minutes that were recorded, the committee’s communications to public commenters, and the forms ISA was required to submit to ANSI throughout the process.  

While much of the process was carried out correctly, there were a few procedural errors that were made. ANSI is requiring ISA and the Z133 Committee to correct these procedural steps before the draft can be approved. Some of these errors have already been corrected, while others are in progress. These corrective action steps are purely procedural and do not reflect on the committee’s exemplary efforts to improve the content of the standard.  

The timeline for completing these steps can be carried out within a few months. However, ANSI notified ISA that their second audit of the corrected process steps could be delayed due to staffing shortages on their auditing team. Considering these factors and ANSI’s feedback, the current projection for publication of the new Z133 standard is between April and July 2026. This timeline is subject to change. Updates can always be found on the Z133 website.   

Until ANSI approval is granted and the new standard is published, the ANSI Z133-2017 remains the standard of reference for OSHA and the standard arboricultural operations in the United States are required to comply with.