Pesticide Registration Toolkit

Operator exposure measurements


Operator exposure measurement are normally only required when there are no representative scenarios available in operator exposure models, or where the model-based risk assessment indicates that the acceptable operator exposure level is exceeded.

Operator exposure studies should provide sufficient data to permit an evaluation of the operator exposure likely to arise under the locally proposed conditions of use.


Operator exposure studies should normally be conducted according to the principles of Good Laboratory Practice (GLP) as applied to field studies.

Study methods that may be used for the assessment of exposure include passive dosimetry (e.g. patch method, whole body method, hand exposure method and personal air samplers to measure inhalation exposure) as well as biological monitoring of absorbed dose of the pesticide (e.g. urine and/or blood sampling).

Detailed guidelines on conducting field studies of occupational exposure to pesticides during agricultural application are provided by the OECD, which can be found here.


A good report on operator exposure studies should contain the following information:

  1. test material, purity, stability, product specification of formulation, batch numbers, nominal and actual concentrations;
  2. description of study design;
  3. exact locations of study sites, including site maps;
  4. description of mixing, loading and application equipment, clean-up procedures, application rate(s), crop areas treated/harvested, number and length of tasks for each worker;
  5. description of work procedures of workers, to include any use of protective clothing and equipment;
  6. detailed description of all sampling methods used, e.g. dermal, inhalation, biological monitoring, environmental conditions, field recovery evaluation;
  7. conditions of sample storage and shipment;
  8. description of analytical methodology, extraction, detection, validation;
  9. calculations and extrapolation factors;
  10. results of analysis, to include uncorrected and corrected residues, laboratory and field recoveries, extrapolated exposure and absorbed dose values, environmental conditions;
  11. tabulation of: all relevant analytical data; extrapolation results, e.g. dermal, inhalation, exposure, absorbed dose (from biological monitoring); environmental conditions;
  12. photographic record;
  13. discussion and interpretation of results;
  14. conclusions;
  15. location of raw data;
  16. references.

Interpretation of the outcome

The registrar should assess whether the exposure study is relevant for the intended us of the pesticide submitted for registration, and should be representative of the operator population at risk. Therefore, the study design should follow application procedures, dose rates, protective clothing, and application equipment as will likely be recommended on the label.

Detailed information on study design and quality control occupational exposure studies, relevant to the interpretation of their results, can be found in the OECD guidance mentioned above.