Most newer vaporizers come with key-indexed ports designed to accept a filling device (called a key) which is agent specific and fits securely into the port to avoid spillage. The keys are color-coded for each anesthetic. The filling and dumping ports on the vaporizer are accessed by opening the respective screws and caution must be exercised to avoid opening the screw for the dumping port when intending to fill the vaporizer (a dangerous error that can easily occur). Make sure to tighten these securely after filling or dumping.

For those with network access, a video can be observed that shows opening of the key-indexed filling port. The section on Equipment: Empty Inhalant under Awareness/Assessment shows opening the dumping port.

Some vaporizers (usually older models) require the liquid anesthetic to be poured into a funnel opening with a screw seal. The screw must be tightened securely after filling. These are simple to use, but susceptible to over-filling and spilling of the liquid anesthetic. Some improvement in safety during the filling process can be achieved if a special pour filling device is used. Better accuracy with less dripping on pouring is achieved (see network video showing use of the pour filling device).