The apparatus and method for venting and depressurization of an odorant injection system may be used on special LNG tankers that have onboard gasification equipment, on land or elsewhere. Odorant injection systems may operate at high pressures on an intermittent basis. On some occasions, the odorant is drained from a pressurized system and disposed of in inappropriate ways. The present invention depressurizes an odorant injection system and transfers the unwanted liquid odorant back into an odorant tank where it can be reused when the odorant injection system is restarted.