Improved Safety: No arc chutes and enclosed vacuum interrupters with sealed contacts eliminate potential hazards resulting from exposed arcs or environmentalcontamination.
改善的安全：弧不滑下并且附上的真空阻碍者以被密封的联络消灭潜在危险起因于被暴露的弧或环境污染。
2
PCBs (Polychlorinated Biphenyls), once widely used for industrial purposes but outlawed as carcinogenic in 1976, can also be found in fish due to environmentalcontamination.
PCBs(多氯联苯)，一度广泛用于工业用途，但在1976年作为致癌物被取缔。
3
Environmentalcontamination was tending to become worse in terms of the industrial development. Our strategy must be taken to control of the pollution while pollutants are produced.