Table 2. Descriptive characteristics of 432 workers exposed to Indium compound more than once.

Wears dust respirator	Always	414 (95.8%)
	Sometimes	3 (0.7%)
	Not	11 (2.5%)
	No answer	4 (0.9%)
Experience of massive exposure	Yes	0 (0%)
	No	427 (98.8%)
	Unknown	5 (1.2%)
Chest radiograph findings	No findings	400 (92.6%)
	Pleural adhesions	7 (1.6%)
	Sclerotic lesions	5 (1.2%)
	Others	20 (4.6%)
Serum indium (µg/L)	Mean ± SD	0.15 ± 0.26
Exceeded standard value (3 µg/L)		1 (0.2%)
KL-6 (U/mL)	Mean ± SD	231.59 ± 88.48
Exceeded standard value (500 U/mL)		9 (2.1%)

Notes.

SD, standard deviation