Nrog kev nce qib ntawm kev siv thev naus laus zis, cov ntawv thov ntawm PCB hloov pauv ntawm cov khoom siv cov pob khawm zoo nkauj, hauv cov khoom siv hluav taws xob siab, hauv cov khoom siv kho mob kub lub sijhawm, lub tsheb hluav taws xob hauv cov chaw siv hluav taws xob tseem ua rau siv cov txiaj ntsig puv ntawm cov hluav taws xob hloov tau zoo {}}
Nrog sawv ntawm kev ncab hluav taws xob thiab cov luam tawm hluav taws xob, tab sis kuj ua rau muaj kev sib tw ua kom zoo dua qub, tab sis kuj ua rau muaj kev sib tw tshiab kev txawj ntse, uas yuav qhia ntxiv cov kev txwv ntawm cov khoom ua tau zoo thiab sau tshooj tshiab rau kev lag luam hluav taws xob.
