Heavy Metals

Efforts by auto makers to eliminate heavy metals, such as lead and mercury, are nearly complete — just in time for new European legislation banning use of the potentially dangerous materials.

Although there are some exemptions, European Union countries in July began barring sales of vehicles that contain the four main heavy metals. In addition to mercury and lead, the other heavy metals commonly used by auto makers are cadmium and hexavalent chromium.

The materials are toxic and proven to cause numerous health problems. But for decades they were used in auto applications. Since the 1980s, the industry has worked hard to remove heavy metals from components such as switches, fasteners, paint and fuel tanks.

But the European regulations kicked the effort into overdrive. With global purchasing operations and models shipped around the world, continuing to use heavy metals in non-EU regions could cause major headaches.

“Really, it's being driven by both the European level of regulations and then some local (U.S.) state things,” says Ron Michalak, technical integration engineer-General Motors Corp.'s Materials Group.

“But this is going to be eventually across the board. We're cleaning up our end of the business in advance of what is mandated.”

Maine banned the sale of new vehicles containing mercury switches effective Jan. 1. The legislation, passed in April 2002, also includes the nation's first mandate making manufacturers responsible for the removal of toxic mercury from vehicles currently on the road.

Auto makers must offer to remove mercury-laden switches at no charge to consumers, pay a minimum of $1 bounty for each switch turned in and pay for the transport and recycling of switches. Other states are considering similar legislation.

Mercury also was used in antilock brakes. Mechanical processes have replaced the unusual metal, which is liquid at room temperature, but so dense that bowling balls float in it.

However, mercury is exempt from the European ban in high-intensity discharge (HID) headlamps and navigation screens because of the safety benefits those systems provide. “But certainly the amount of mercury in a vehicle today is greatly reduced from what it used to be,” says Dan Adsit, recycling program manager for Ford Motor Co.

Osram Sylvania Global Automotive Lighting reports it is developing mercury-free HID light sources. One HID headlamp has a mere 0.5 mg of mercury — about enough to sit on the head of a pin. Still, the company knows it needs to eliminate mercury and says eventually there will be no cost difference for mercury-free HIDs.

Auto makers also are making serious headway eliminating cadmium, a pigment for paint. “We took it out of the paint,” says a Chrysler Group spokeswoman. “Now we use an organic pigment instead of the metallic pigment.”

Efforts to eliminate lead and hexavalent chromium aren't progressing as quickly. Lead remains in batteries, but it's no longer utilized as a finishing material for steel to improve formability. For instance, auto makers began phasing out terne-plated steel fuel tanks over the last decade to abolish the use of a lead-tin alloy. A majority of fuel tanks now are plastic. “Or we've gone to different finishes for steel,” Michalak says.

Hexavalent chromium is an effective corrosion inhibitor that often is used for fasteners and fuel lines. The Southfield, MI-based Vehicle Recycling Partnership task force predicts hexavalent chromium will be eliminated by 2007. Some auto makers may successfully phase out hexavalent chromium as early as 2005, VRP says. Zinc-based materials and polymers are replacing hexavalent chromium.

“In some cases, you can make a quick switch, an easy switch,” says Michalak. “And in some of the others, it's taken some extensive development. We've been working diligently with our supply base for many years to make these alternate materials available.”