Primrose Oil - (800) 275-2772 Home lubricant and fuel treatment, Primrose Oil Company, Primrose Plus, Premium Select, Syn-O-Gen®, Enviro Blend® Since 1916, Primrose Oil Company has been at the forefront of the lubricant and fuel treatment industries. Primrose Plus, Premium Select, Syn-O-Gen®, and Enviro Blend® highlight our commitment of maintaining leadership in these industries.