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Department of Pesticide Regulation
Agricultural Commissioner Liaison

April 14, 1999
CACL 99-01

To: County Agricultural Commissioners


On April 5, 1999 a conference call was held with most of the cotton growing counties and the Department of Pesticide Regulation (DPR) to discuss the recently completed risk assessment on DEF. Also discussed were the unacceptable exposures identified in the assessment. The most immediate consideration involves mitigating unacceptable acute occupational exposures.

Two occupational activities posed unacceptable acute risks; they are harvester operators and trampers. As a follow-up to the conference call, DPR and the commissioners agreed to evaluate the predominance of tramper practices.

DPR explained, based on monitoring data, harvesting activities would need to occur 14 days after application. It was unclear at the time of the conference call if harvester operators had climbed out of the harvester at any point during the study. (The label allows harvesting after seven days and since harvesting is considered a non-contact activity, the practice could occur as soon as 24 hours post application.) The average harvesting activities occur ten days after application. The harvesters in the studies operated with their windows open. Harvesting could commence after seven days if the cab windows were closed. Three issues were raised for consideration:

  1. Should the mitigation measures be imposed through DPR regulations or through modifications to existing permit conditions?
  2. Should the mitigation measures be based on "open windows" or offer less restrictions if windows were closed?
  3. Should the restrictions refer to reentry intervals or preharvest interval?

The commissioners were going to discuss these items at their area group meetings and follow up with DPR at the Spring Conference. The goal is to have the restrictions in place by the upcoming defoliation season. DPR will inform the California Aerial Applicators Association of the completed risk assessment.

I expect to hear additional questions and comments because there were several cotton growing counties unable to make the conference call. For more information, please contact Mr. Roy Rutz at (916) 445-4279, or e-mail at ( As always, I am available should you have comments, concerns, or need further assistance.


Original signed by:

Daniel J. Merkley
Agricultural Commissioner Liaison
(916) 445-3906

cc: Mr. Roy Rutz, Program Supervisor III