The Facts Behind Mercury Free

The predecessor to zinc air batteries for use in hearing aids were mercuric oxide batteries. These batteries contained relatively high amounts of mercury (greater than 50% by cell weight). When zinc air batteries came on the scene in the late 1970's, their superior performance and reliability quickly replaced mercuric oxide as the battery chemistry of choice. Mercuric oxide batteries were banned in 1996.

But even standard zinc air batteries contain added mercury, about 1% by cell weight. The mercury is fused with the zinc powder used in the cell. Because mercury is a metal, it is a good electrical conductor and its properties help suppress internal gassing in the cell. This gassing can lead to leakage or swelling of the battery.

It is a common misconception that all hearing aid batteries are mercury free. This stems from the 1996 legislation that banned mercury from household alkaline batteries. At this time button cells such as hearing aid and watch batteries were exempt because technology to create a mercury free design in these cells was not available.

Mercury is a heavy and toxic metal. It is extremely harmful to the environment. One way that mercury gets into the environment is through throwing away mercury containing batteries. When someone throws away their mercury containing hearing aid batteries, these batteries start to decay in the landfills. Over time, the battery will start gassing and the mercury inside has a potential of leaking out. This mercury can seep into the ground, contaminating drinking water, and into streams. The wildlife that lives, eats, or drinks from these streams will be exposed to this mercury resulting in death, contamination, or deformities in offspring.

People are exposed to mercury most commonly when they eat food contaminated with mercury, especially fish. Long term exposure to mercury can permanently damage the brain, kidneys, and fetuses. Over 66,000 children are born each year with risk of neurodevelopment issues due to mercury exposure as a fetus.

Numerous US states have enacted legislation, effective as early as June 30, 2011, that bans the sale, offer to sell, or distribution for promotional purposes of mercury containing button cell batteries, including zinc air hearing aid batteries. States with enacted bans include Connecticut, Maine, Rhode Island and Louisiana. These legislations have caused many manufacturers to switch to offering mercury free hearing aid batteries. The following lists the specific information related to these bans and links to each state’s legislation.

Maine - effective date January 1, 2012

Connecticut - effective date July 1, 2011

Rhode Island - effective date June 30, 2011

Louisiana- effective date 2012

Rayovac has dedicated 7 years to researching and developing a mercury free zinc air battery. The results were a zero mercury anode formulation made up of a proprietary organic "cocktail" that maximizes capacity retention (fade over time), quality and reliability. In 2009, Rayovac launched its first generation mercury free battery, over two years before they were required by state law. Committed to improving this battery, the new second generation mercury free battery was launched in 2010.

Rayovac’s new, improved performance mercury free product is the World’s Longest Lasting Mercury Free hearing aid battery. This second generation design now provides higher voltage (1.45V) and long life. The second generation design combines performance in both capacity and voltage that are almost identical to Rayovac’s mercury containing cells. It is designed for resistance to leakage, swelling and corrosion. We are also pleased to say that the majority of major global hearing aid manufacturers are either buying or have approved the Rayovac second generation design for use in their hearing instruments.

By the 2011 mercury free deadline, Rayovac will be not only be serving the states with current legislation, but serving the whole nation with their mercury free product. This will include our new Mercury Free Cochlear product, launching June 2011.

We hope that this information answers many of your questions regarding mercury free hearing aid batteries. If we can be of further service, please contact one of our representatives at 1-800-356-7422.