There is no end of life to the mercury vapor lamp, but this may not safe for your health. Mercury vapor just keeps burning and burning. These light bulbs practically never burn out, but they do need replacement as they gradually dim over time. They continually give off light, still consuming the same amount of energy as when new, but the mercury vapor lamps do tend to make people look like "bloodless corpses."
So is a product like this really safe or not?
To start off, this light bulb DOES contain mercury that DOESN'T disappear over time. This is a health concern. Then, when the bulbs are thrown away, the mercury goes into the trash heap, the landfill, and the ground water. And keep in mind that the mercury is NOT the only noxious chemical used to keep these lamps going and going.
To correct the bluish tinge, many mercury vapor lamps are coated on the inside of the outer bulb with a phosphor that converts some portion of the ultraviolet emissions into red light. This helps to fill in the otherwise very-deficient red end of the electromagnetic spectrum. These lamps are generally called "color corrected" lamps. Most modern mercury vapor lamps have this coating. The reason they make people look like a bloodless corpse is because of the lack of light from the red end of the light spectrum. There is also an increase in red color due to the continuous radiation in ultra-high pressure mercury vapor lamps.
OK - let's back up and re-read that last statement: "There is also an increase in red color due to the continuous radiation in ultra-high pressure mercury vapor lamps." I am most concerned with this continuous radiation in these lamps. THIS is not a safety feature to have inside your home, near your children and pets, or in our landfills.
To better understand the serious health and environmental threat these mercury vapor lamps can create, it's helpful to understand how they work.
When the mercury vapor lamp is first turned on, it will produce a dark blue glow because only a small amount of the mercury is ionized and the gas pressure in the arc tube is very low, producing most of the light in the ultraviolet mercury bands. As the main arc strikes and the gas heats up and increases in pressure, the light shifts into the visible range and the high gas pressure causes the mercury emission bands to broaden, producing a light that appears more white to the human eye, But it is still not a continuous light spectrum. Even at full intensity, the light from a mercury vapor lamp with no phosphors is bluish in color.
A mercury-vapor lamp is a gas discharge lamp, which uses mercury in an excited state to produce light. The arc discharge is generally confined to a small fused quartz arc tube mounted within a larger borosilicate glass bulb. The outer bulb may be clear or coated with a phosphor to provide thermal insulation and protection from ultraviolet radiation.
Mercury vapor lamps are being used more and more these days because they are relatively efficient. Many state governments are now requiring all lighting be the mercury vapor lamps to save on energy use, and the Federal government has proposed on the national level making this type of lighting mandatory in the United States.
Mercury vapor bulbs are typically used for outside lighting, on signs and light poles, and for auditoriums and stages. Again, are using these bulbs INSIDE safe? And are these bulbs polluting the environment?
All mercury vapor lamps (all metal halide lamps, actually) must contain a feature or be installed in a fixture that contains a feature to prevent ultraviolet radiation from escaping. Usually, the borosilicate glass outer bulb of the lamp performs this function, but special care must be taken if the lamp is installed in a situation where this outer envelope is damaged. There have been documented cases of these lamps being damaged in gymnasiums and creating sunburns and eye inflammation after exposure. When used in locations like a gym, the light fixture should contain a strong outer guard or an outer lens to protect the lamp's outer bulb from breaking. Also, special "safety" lamps are made which deliberately burn out if the outer glass is broken. A thin carbon strip is used to connect one of the electrodes, which will burn up in the presence of air. But, is THIS modified bulb any safer for your health or for the environment? Likely not.
So, what happens to you, your child or your family pet if one of these bulbs bursts inside your home? Over time, will caution be forgotten and more health dangers be inflicted on the consumer?
Even with caution taken, some UV radiation can still pass through the outer bulb of these lamps. This causes the aging process of some plastics to speed up, leaving them significantly discolored after only a few years' service. This also exposes you, your child and your family pet to harmful UV rays, and at a close distance, I might add, if placed on a table in a lamp. And the more people that buy these mercury-containing lights, the more toxic the environment will become.
Cutting back on lighting and energy use is the best solution to this intensifying issue. Sprawling metropolitan areas, high-density housing developments, shopping complexes and parking lots are all energy/lighting hogs. Have you noticed how many downtown buildings remain illuminated during the night? Or how many bright lights beam over shopping malls and grocery store parking lots after shopping hours are over? And maybe the 24-hour drive-through eating-places need to return to closing at the late hours after dark to save on energy use. These are all easy solutions to saving energy.
Looking for safer energy technology is another prudent solution, and one that favors the entire global community versus the pocketbook of only a few investors. Proper recycling of discarded mercury vapor lamps is also an easy solution, and one that actually creates more jobs. Many countries like Germany have excellent recycling practices employing many people to collect and recycle all types of products, rather than randomly discarding them in a landfill. Sadly, merely a few states in America have user-friendly recycling practices, so people are disposing of toxic products, like the mercury vapor lamps, directly into the landfills and groundwater. If consumers increase their use of mercury vapor bulbs, then safer ways of disposing of them MUST be provided.