Batteries: Hazardous Waste or Not?

The widely held belief that batteries should categorically be brought to Household Hazardous Waste collections for proper disposal needs some fine-tuning. Today, the battery types that continue to require special disposal are: rechargeable nickel-cadmium (Ni-Cd) and nickel metal hydride (NiMH) batteries, small sealed and automotive lead acid batteries, and lithium, mercuric oxide, silver oxide batteries. [Applications powered by these batteries]

It is the heavy metal content of batteries that causes concern. While in the battery, the heavy metals pose little risk. The problem comes upon disposal. When landfilled or incinerated, the heavy metals could leach out into soil or water, or escape in smokestack emissions or leach out from ash, respectively. The metals of concern here are cadmium, lead, mercury, and nickel. Exposure to any of these can lead to serious health complications, often fatal, to humans. And, they can be generally toxic to the environment as well.

The alkaline and heavy-duty (zinc carbon) batteries, both non-rechargeable and rechargeable, found in general household use can be safely disposed of in the regular trash if they were purchased after mid-1996. This was not always the case, as these batteries contained mercury. The removal of mercury from battery "ingredients" is an example of how a manufacturing industry responded to environmental concerns.

In the early to mid-1990's, individual states -- Maryland among them -- began enacting legislation requiring recycling of certain batteries and limiting the mercury content of others. At the same time, "mercury-free" batteries began to appear on store shelves. In May 1996, the Federal Battery Bill, also known as the Mercury-Containing and Rechargeable Battery Management Act was signed.

This Act stipulates that all alkaline manganese and zinc carbon batteries (conventional flashlight batteries, for example) sold after that date contain no more than 25 mg per cell. This figure refers to mercury added to the battery formulation; some battery ingredients contain very low amount of mercury themselves. The sale of button cell mercuric-oxide batteries is prohibited altogether. Other mercuric-oxide batteries cannot be sold unless the manufacturer identifies a collection site for the spent batteries and informs the customer of this site.

Ni-Cd and certain small sealed lead acid (SSLA) batteries now have to meet a labeling requirement and be easily removable from consumer products. The Act also paved the way for the recycling of these batteries, in part by easing hazardous waste transportation regulations that had acted as barriers to recycling for batteries. (It was recognized that batteries don't have quite the "nastiness" factor that is inherent in many other materials classified as hazardous.)

Additionally, both the US EPA and battery manufacturers and sellers were charged with educating the public about the need for Ni-Cd and SSLA battery recycling, and about how to participate in recycling programs for these battery types.

Once received at a recycling facility, both kinds of batteries are ground up for further processing. In the case of lead acid batteries, the cases (usually made of polypropylene) are turned into new battery cases. The lead grids, oxides, and other lead parts are melted together and used to make lead plates and parts for new batteries. The sulfuric acid has one of two fates. Either it is neutralized, treated, and then released into a public sewer system or it is converted to sodium sulfate, which is used in laundry detergent as well as glass and textile manufacturing.

Ni-Cd batteries are handled similarly. After shredding, cadmium is extracted and used in making new batteries. The nickel and iron are applied to the production of stainless steel products.

References

Batteries requiring special disposal

The following battery types, followed by their most common applications, should continue to be taken to Household Hazardous Waste collections or other battery recycling collections.

Lithium:

computer memory and real time clock backup, electronic counters, process controllers, portable instruments, time/data protection, industrial controls, electronic gas, water and electric meters, communication equipment, watches, protection of control parameter memory, portable electronic devices

Nickel cadmium:

cameras, data terminals, FAX and POS memory, hobby remote controls, notebook PCs, portable phones, transceivers, portable printers, portable TVs, CD and tape players, power tools, vacuum cleaners, shavers, security lights, toys

Nickel metal hydride:

car telephones, cameras, cellular mobile telecom products, notebook PC's, personal digital assistants, portable VCRs, TVs, portable stereos and CD players, cordless vacuum cleaners, applications where high-energy and small size are critical

Small sealed lead acid:

communication equipment, office equipment, security systems, power tools, toys, UPS systems

Silver oxide:

digital watches, calculators, portable medical devices, hearing aids (often replaced with zinc air batteries), remote telemetry devices, continuous power-on devices

Zinc oxide:

digital watches, calculators, portable medical devices, remote telemetry devices, continuous power-on devices

Last edited: 6/30/2008