Mercury Vapor lighting is the oldest and least efficient of the HID (High Intensity Discharge) family. At this point mercury vapor lights are fairly uncommon in the Boise metro area.
Mercury vapor lights generally have rated life time of over 20,000 hours and provider a blusish white light color. Mercury vapor lights have always had poor lumen depreciation, meaning that the bulbs get very dim over time. They do not maintain their intial brightness very well.
Due to the Energy Policy Act of 2005 the mercury vapor bulbs and ballasts have been phased out. After December 31, 2008 the manufacture or importation of new mercury vapor light bulbs and ballasts were forbidden. So there is no new supply of mercury vapor bulbs or ballasts coming onto the market.
Many mercury vapor fixtures have been now changed out to either high pressure sodium lighting or metal halide lighting. We have also seen people deballast the mercury vapor light fixtures and use large self ballasted CFL light bulbs.
There are now many LED options for these style of lights. It generally makes more economic sense to purchase a new LED fixtures for these style of lights rather spending money maintaining the old mercury vapor fixture.
If your facility still has mercury vapor lights you may want to look at upgrading. There are many options that may qualify for Idaho Power lighting incentive money.