Proposed Changes for Use-Restricted Herbicides

The current use-restricted herbicide rules for Eastern Washington are very outdated and redundant. The Washington State Department of Agriculture (WSDA) formed a workgroup to update and consolidate these rules. The WSDA is currently requesting comments on these changes prior to filing the paperwork to open the public comment period. In order to file on time, they are requesting comments by Monday, October 15th. Public hearings are expected to be held in early December.

The rule changes and explanations can be found below:

The most extensive changes are to the nozzle/pressure requirements, which will now become “droplet spectrum” requirements, which work like this:

  • The statewide rules (WAC 16-230-655) will require ground applications to use nozzles/pressure that creates a Medium or larger droplet spectrum. This is the minimum or baseline for all of Eastern Washington
  • Areas 1, 1A and 2, which are more sensitive, will require ground applications to use nozzle/pressure that creates a Coarse or larger droplet spectrum
  • Where there are exceptions to sunset/sunrise restrictions, or inversion conditions, by using higher gallon/acre rates, applicators must use a Very Coarse or larger droplet spectrum
  • The statewide rules (WAC 16-230-670) will require aerial applicators to use a Coarse or larger droplet spectrum. Prohibitions on aerial applications will be retained.

These changes will allow us to eliminate quite a few subsections in both the statewide and the individual county rules. The other changes include:

  • Eliminating the one-mile vineyard buffer for aerial applications in individual counties since the same requirement is in the statewide (WAC 16-230-665)
  • Eliminating the 85˚ temperature cutoff in individual counties since the same requirement is in the statewide (WAC 16-230-640)
  • Eliminating aircraft mix/load restrictions as unnecessary (can cite general pesticide rules for incidents)
  • Eliminating storage restrictions (can cite general pesticide rules for incidents)
  • Eliminating restrictions on oil carriers and adjuvants (outdated).

Be sure to watch for the announcement on the public hearings. These rules will affect all agricultural producers in Eastern Washington. The use-restricted herbicide rules are in need of updating. Be sure you know how the updates affect you.


Please provide any comments you may have about these proposed changes to Joel Kangiser, Compliance Program Manager with the WSDA in Olympia, at 360-902-2013 or JKangiser@agr.wa.gov. You may also contact Scott Nielsen in the WSDA Spokane office at 509-990-6518.

Washington State University