Sulfuryl Fluoride Label Changes for Structural Fumigation (Vikane and Zythor)

Sulfuryl fluoride is a California restricted material and a federal Restricted Use Pesticide (RUP). In 2023, as a result of the final early mitigation decision for sulfuryl fluoride used to fumigate residential structures, the U.S. Environmental Protection Agency (U.S. EPA) required registrants of sulfuryl fluoride to amend product labels with additional protective measures. This letter summarizes those changes and provides guidance on Site-Specific Fumigation Log requirements.

CAC staff should review the new labels to familiarize themselves with the updated requirements. While not a comprehensive list, the revised labels include the following changes:

• Updated stewardship plan training requirements.
• Added Site-Specific Fumigation Log Requirements.
• Under “Preparation for Fumigation”, the term “storage chests” was replaced with “furniture with large voids (such as wardrobes, etc.)”. (Vikane Label only)
• Added definition of “Residential Structures”.
• Adopted changes to Aeration Procedure 1 and Aeration Procedure 2.
• Expanded the “Securing Structures” section to include the use of “Electronic keycard and “keyless” locks” within specified guidelines.  (Vikane Label only)
• Updated “Clearance Testing Equipment” section to update the previous calibration requirement and include the U.S. EPA website description for a list of effective clearance devices.

Site-Specific Fumigation Log Requirements

The revised labels for both Vikane and Zythor both require Site-Specific Fumigation Logs. These Site-Specific Fumigation Log requirements mandated by the label differ from those required by the Standard Structural Fumigation Log (Form number 43M-47, Rev. 6/2023) under Title 16, California Code of Regulations (16 CCR) section 1970(a). A rulemaking package is required to update 16 CCR section 1970(a) to update the existing 43M-47 form with fields for the new label Site-Specific Fumigation Log requirements.

When using the new registered label, applicators must meet the current regulatory requirement under 16 CCR section 1970(a), and the label required Site-Specific Fumigation Log. While many of these requirements overlap, there are several new label criteria which must be documented in addition to the required information in the Standard Structural Fumigation Log.

The Department of Pesticide Regulation (DPR) developed an Interim Structural Fume Log Supplement form (enclosed) to be used in conjunction with the Standard Structural Fumigation Log to meet all the new labeling requirements. This interim form developed by DPR is not required to be used, and applicators can fulfill both requirements by using a complete Standard Structural Fumigation Log (Log), plus documenting the additional label requirements on either the Log, an industry-created form, contract, or any other document prepared for and used during the fumigation.

If you have any questions, please contact the Enforcement Branch Liaison assigned to your county.

Sincerely,