The invention discloses a rubber process oil and a process for manufacturing rubber process oils which are non-carcinogenic in nature. The process comprises of selectively producing Hildebrand solubility components enriched vacuum residue by selective distillation of reduced crude oil (RCO) to obtain minimum of 10 vol % boiling components in the range 490° C. to 50° C., which leads to higher solubility of rubber process oil with an aniline point of less than 70° C. and with extremely low concentration of selective polycyclic aromatics which makes the 15 product non-carcinogenic. The process comprises of selectively enriching higher Hildebrand solubility components in vacuum residue by vacuum distillation of reduced crude oil (RCO), then subjecting the enriched vacuum residue to solvent deasphalting process and subjecting the deasphalted oil to aromatic extraction process and then blending the enriched aromatic extract with Heavy Alkyl 20 Benzene (HAB) or Solvent processed base oil or hydroprocessed base oil or mixture thereof. The rubber process oils manufactured by the invented process have a polycyclic aromatics (PCA) content of less than 10 ppm, specifically benzo(a)pyrene content of less than 1 ppm. They have aniline point less than 70° C. but have high kinematic viscosity of 25 to 75 cSt at 100° C., pour point of 27° C. or less and a flash point minimum of 250° C. or more.