Field evaluation of the protection afforded pesticide workers by apparel lis an emerging research area. The design of experiments is critical for obtaining unequivocal data upon which to base recommendations.

The simplest design is a penetration study using collection devices inside and outside the clothing. The residues on inside devices are compared with the residues on outside devices to calculate “protection.” The residue proportion between inside and outside devices may be as large as 1:99. Although proportions this large are helpful for establishing statistical differences, this design still presents certain problems for the analyst.

A second design utilizes urine only. A 24-h urine specimen is collected. The worker wears the garment for one week and removes it the next. Changes in the concentration of residues in urine allow calculation of protection. This design may be flawed by extraneous exposure, uncertainties about urinary excretion kinetics, or nonurinary excretion routes.

A third design combines the first two, but unfortunately a new set of experimental considerations then emerges.

This manuscript discusses the statistical, chemical, metabolic, and human problems inherent in the three designs, with special reference to the experimental goal of each design.