Site observation and sampling collection
The incense making process was studied to consider the risk of dermal contact
of each step and photos were taken to explain clearly incense making steps. Moo 12
of Ngooleum village had around 100 small household factories that making incense
stick. Each small household factory had at least 5 incense workers, so male workers
worked all of duties but incense packing step always work by female workers. Thirtyfive small household factories were selected randomly by house number were
representative groups of incense workers in the study area. Thirty sampling (n=30) is
the least number in order to make a good estimation for population mean, so the case
study selected 35 incense workers (Jaipieam, 2008; Ling, 2012). Each small
household factory were collected the three sample groups as dissolved dye, incense
stick, and hand wiping samples. The hand wiping technique was used to collected
hand wiping samples from workers’ hands. The diagram of sample collection was
showed in Figure 3.3