There are now more than one million hybrid gas-electric vehicles on American roads. Many will celebrate reaching the milestone of one million hybrids zipping around on power from their rechargeable batteries—and burning a lot less petroleum. But some environmentally motivated car buyers are concerned about trading one problem for another. They worry that a hybrid utopia might turn into a toxic nightmare when the nickel metal hydride batteries in today’s hybrids end up in landfills. After all, aren’t all car batteries —conventional lead acid and hybrid batteries alike—filled with the same nasty corrosive carcinogenic ooze?

According to environmental researchers, that’s not the case. Jim Kliesch, author of the "Green Book: The Environmental Guide to Cars and Trucks" told, "There are many types of batteries. Some are far more toxic than others. While batteries like lead acid or nickel cadmium are incredibly bad for the environment, the toxicity levels and environmental impact of nickel metal hydride batteries—the type currently used in hybrids—are much lower."

Get the Lead Out

There’s little argument that lead is extremely toxic. Scientific studies show that long-term exposure to even tiny amounts of lead can cause brain and kidney damage, hearing impairment, and learning problems in children. The auto industry uses over one million metric tons of lead every year, with 90% going to conventional lead-acid vehicle batteries.

According to a 2003 report entitled, "Getting the Lead Out," by Environmental Defense and the Ecology Center of Ann Arbor, Mich., an estimated 2.6 million metric tons of lead can be found in the batteries of vehicles on the road today.

While lead recycling is a mature industry, it’s impossible to rescue every car battery from the dump. More than 40,000 metric tons of lead are lost to landfills every year. According to the federal Toxic Release Inventory, another 70,000 metric tons are released in the lead mining and manufacturing process.

Can We Talk?

"Lead is so cheap. It’s difficult to get people to seriously discuss replacing lead batteries in a conventional vehicle" said Karen Thomas, state policy manager at Environmental Defense, in an interview with Ironically, the emergence of hybrid cars, the necessary advancement of alternative batteries to satisfy the hybrid demands, and worries about the toxicity of hybrid batteries, have re-opened the environmental debate about all car battery technology. "It’s providing an opportunity for us to talk about it," said Thomas.

Hybrid gas-electric vehicles, like the Toyota Prius, are the most visible examples of how cars are becoming more electrical and less mechanical. Vehicles with conventional drivetrains are increasingly using electronic technology, such as drive-by-wire and brake-by-wire. Cars are adding more and more onboard accessories and entertainment. Thomas said, "Lead is so heavy. You can’t just add more or larger lead-acid batteries to accommodate the increased electrical demands. Some say lead is at its limit."

Lead, Nickel, Lithium—In That Order

The need for more robust battery technologies to power vehicles and their accessories prompted Environmental Defense to conduct a three-month research effort in 2005 to examine environmental impacts related to the extraction, manufacture, use, and disposal of nickel metal hydride batteries, as well as lithium ion—which many consider to be the battery of choice in the next five years. Environmental Defense then compared those impacts to lead acid. "Our initial conclusion is that lead is the worst, nickel is next, and lithium is the least harmful," said Thomas. This will greatly depend on what materials are combined with lithium, and how toxic those materials are. Using cobalt, for example, in lithium ion batteries would be problematic. It will also depend on the emerging recycling technologies.

While not nearly as dangerous as lead, nickel is not without some environmental risks, and is considered a probable carcinogen. There are also concerns about the environmental impacts of nickel mining, and apparent challenges with fully recycling the nickel used in hybrid batteries.

Hybrids are still sold an relatively low numbers. As a result, large-scale environmental threats from hybrid batteries are not immediate. Hybrids were introduced in the United States in 2000. Hybrid batteries are under warranty for eight to 10 years, depending on the manufacturer and your location, most likely won’t fail for several years beyond the warranty. In the first few years, hybrids sold in low numbers—growing from less than 10,000 in 2000, to 35,000 in 2002. By all calculations, the challenge of recycling hybrid batteries is at least five years away.

Greener Pastures for Car Batteries

The carmakers are waiting in the wings. Toyota and Honda place decals with a toll-free number on their hybrid battery packs. Toyota offers a $200 bounty to ensure that every battery comes back to the company. In a press release, Toyota states, "Every part of the battery, from the precious metals to the plastic, plates, steel case and the wiring, is recycled." Honda collects the battery and transfers it to a preferred recycler to follow their prescribed process: disassembling and sorting the materials; shredding the plastic material; recovering and processing the metal; and neutralizing the alkaline material before sending it to a landfill.

Honda, Toyota and the entire auto industry are pumping millions of dollars into research regarding lithium ion batteries for tomorrow’s cars. Their primary motivation is to reduce the cost and increase the potency of hybrid batteries. Fortunately, supplanting lead and nickel batteries with rechargeable lithium batteries is also promising from an environmental perspective. Instead of clogging landfills with more toxic chemicals, hybrids—especially future hybrids powered by lithium ion batteries—may represent greener pastures for car batteries.