Gov. Linda Lingle has released $4.9 million for the construction of a second electrical vault at Honolulu International Airport to ensure 100 percent emergency backup power for its airfield operations.

"We are continuing to take proactive measures to keep our airports operational in the event of an emergency power outage," Lingle said.

Currently, one electrical vault powers all of the airport's runway lighting and navigational aids. If it were to fail, the entire airfield would be without power.