Blue alert aboard the USS Enterprise-D
The bridge of the Enterprise-D during blue alert
The bridge of Voyager during blue alert
Blue alert (also code blue or condition blue) was an alert signal status on Starfleet vessels and outposts which is called for in exceptional situations, ranging from environmental hazards to the crew, to docking and separation maneuvers and landing protocols, for ships with the capability.
In the event of an imminent environmental systems failure or disruption, blue alert is called in order to help affected personnel escape or safeguard their lives. (TNG: "Brothers")
On a vessel with landing capabilities, such as the Template:ShipClass, blue alert was called as an indication that the ship was preparing either to land or to take off; the crew would then need to report to code blue stations, in order to aid in the landing/liftoff procedures. Blue alert was not required for landing an Intrepid-class starship, however, as the USS Voyager did make a landing while at red alert. (VOY: "The 37's", "Demon", "Dragon's Teeth")
Blue alert was also used when a Template:ShipClass starship activated its multi-vector assault mode. (VOY: "Message in a Bottle")
- This could also indicate that blue alert would be called on Template:ShipClass ships prior to saucer separation, although this protocol was never referenced in any of the instances of that occurring on Next Generation.
The bridge lighting on the refitted USS Enterprise turned blue when it prepared to enter spacedock. (Star Trek III: The Search for Spock)
The USS Defiant went to blue alert when engaging its cloaking device. (DS9: "The Search, Part I")