-(a)Every machine used for grinding or crushing caustic shall be enclosed, and(b)Where any of the flowing processes are carried on :-(i)Grinding or crushing of caustic;(ii)Packing of ground caustic;(iii)Grinding, sieving, evaporating or packing in a chrome process;(iv)Crushing, grinding or mixing of material or cartridge filling in a nitro or amido process;(v)The insecticides mentioned in item 10 of Schedule I in rule 198 are manufactured , mixed, blended or packed an efficient exhaust draught shall be provided ;
