Roi-Et is located the northeastern region of Thailand. The area is divided into 20 districts, 193 sub districts, and 2,311 villages [7]. In the study, Moo 12 of Ngooleum village in Dongdang subdistrict, Chaturaphak Phiman disstrict was selected because the main occupation of villagers is incense production, and because this village has higher income from incense production than other local villages.
In the study area, there were around 100 small household factories, of which 35 household factories chosen randomly by house number for inclusion in the study [8]. Dissolved dye, incense stick, and hand wipe samples were collected from each household factory. Workers responsible for packing incense were chosen randomly to collect samples by gauze wiping technique. For each factory, 20 ml of dissolved dye samples and incense stick samples were collected and kept in plastic bottles in plastic bags until analysis.
In the gauze wiping technique, two 20% isopropanol gauze pads wipe the hand surface side to side in “Z” wipe pattern, both vertically and horizontally, covering the front and sides and the fingers, 10 seconds per pad [3, 4, 9]. Working day of incense workers was separated into 2 events in the morning and afternoon. Thirty-five workers were collected 3 hand wiping samples: before