Mercury deposits that build up in lakes and streams develop into methylmercury, which can accumulate to harmful levels in fish and the people and animals that consume them. Depending on the level of exposure, methylmercury can lead to reduced fertility, impaired development and behavior, and loss of life. In an effort to further environmental responsibility, the battery industry recently announced an initiative to eliminate added mercury from button cells—the batteries widely used to run watches, calculators, and hearing aids.
The announcement, which was issued by ANSI (American National Standards Institute) member and accredited standards developer the National Electrical Manufacturers Association (NEMA), commits to achieve this goal by 2011. Participating organizations will devote resources to resolve manufacturing challenges and to continue to advance emerging technologies. The Dry Battery Section of NEMA develops industry positions on legislative and regulatory initiatives, and includes ANSI members Duracell, Inc. and Eastman Kodak.
Button cells are currently the only remaining type of battery that contains added mercury. The liquid element had been widely added to batteries to reduce internal gas formations that lead to leakage and shorter shelf life. But due to growing environmental concerns, the battery industry worked to develop alternative products. By 1993 the industry had phased out the addition of mercury in standard size alkaline and carbon zinc batteries; however, limitations in technology prevented elimination of added mercury in button cells, partially due to their small size.
Continued industry efforts resulted in a decrease of more than 1,000 tons of mercury per year. Between 1991 and 1995, the battery industry phased out production of mercuric oxide button cells used in hearing aids, which were prohibited in 1996 under the Mercury-Containing and Rechargeable Battery Management Act. Prior to the recent decision to entirely eliminate added mercury in button cells, the industry had lowered the amount of mercury in button cells to record lows, far exceeding the 25 mg federal limit to less than half this value.