This is normal operation. Many people call this oil mist ``smoke'' that comes from your vacuum pump. It is a trait of every oil-based vacuum pump. During operation, if the freeze dryer unit is not completely sealed (door shut and drain valve closed), oil mist may also leave from these openings. If the oil mist from our standard oil mist filter is not acceptable for the room the freeze dryer is operating in, upgraded activated carbon oil mist filters are available for purchase on our website. Additionally, the oil mist can also be reduced by wrapping a microfiber towel tightly around the standard oil mist filter.