Metal halide bulbs can heat up to temperatures exceeding 2,000 degrees Fahrenheit. A metal halide light that fails can crack, and directly expose flammable materials to these excessive temperatures. ANSI, the American National Standards Institute, offers a classification system that consumers can consult before installing a metal halide light fixture.
Metal halide bulbs contain traces of elemental mercury. While mild exposure to mercury can lead to less severe symptoms such as headache and irritability, over-exposure to mercury can lead to respiratory failure, according to the EPA. A 1,000 watt-metal halide bulb can contain over 81 mg of elemental mercury.
If a metal halide bulb breaks, consumers should evacuate the immediate area, giving the airborne mercury a chance to dissipate. Many facilities across the country like Home Depot offer programs where consumers can bring in their broken or used metal halide bulbs to be recycled. Pieces of the broken bulb can be gathered into a jar, and taken to a recycling facility.