Avoid hazardous substances and chemicals.

避免接触危险物质和化学品。

No harmful gases and hazardous substances to human harm.

无有害气体和有害物质，对人体无害。

Environmental protection, no mercury and other hazardous substances.

环保，没有汞等有害物质。

They failed to ensure clients were not exposed to hazardous substances.

他们未能保证不使客户接触到危险物质。

Yet all of these hazardous substances pose little risk if used properly.

但如果使用得当，所有这些有毒化合物都不会形成危害。