Workplace air safety requires separate exhaust systems, neutralisation of toxic emissions, and safe confined-space entry limits. Employer of every factory must ensure precaution against dust, noxious gas, fumes and other impurities by keeping exhaust systems for flammable fumes, gases, mists, vapours or residues separate from other ventilating systems and combustion flues. Where emissions may adversely affect health or the neighbourhood, exhaust must be routed through systems that neutralise toxic substances, sterilise infectious substances and deodorise fumes, gases, mists or vapours. No employee may enter a workplace or confined space until practicable measures have reduced noxious gas, fumes, vapour or dust to permissible limits.