Txij li thaum nruab nrab Lub Xya Hli, tau txais kev txhawb nqa los ntawm cov khoom muaj txiaj ntsig zoo xws li cov khoom siv hluav taws xob hauv cheeb tsam thiab kev saib xyuas cov khoom siv, kev lag luam hauv tsev calcium carbide tau nce. Nkag mus rau lub Cuaj Hlis, qhov tshwm sim ntawm kev thauj khoom ntawm calcium carbide tsheb thauj khoom hauv cov neeg siv khoom hauv North Tuam Tshoj thiab Central Tuam Tshoj tau maj mam tshwm sim. Cov nqi yuav khoom tau txuas ntxiv txo qis me ntsis thiab cov nqi tau poob qis.Nyob rau theem tom ntej ntawm kev ua lag luam, vim tam sim no tag nrho pib ntawm cov nroj tsuag PVC hauv tsev nyob rau theem siab, thiab muaj tsawg dua cov kev npaj kho tom qab, kev lag luam ruaj khov dema .
