Michigan Releases Study on Mercury Switch Assemblies
Lansing, MI - The participants in the Michigan Mercury
Switch Study released a report that investigated the removal of mercury
convenience lighting switch assemblies in "end-of-life" vehicles.
The report is a result of a study that evaluated the technical, logistical,
and procedural factors associated with the removal of these switches and
their subsequent management. The study was conducted as a joint effort
that included the Michigan Department of Environ-mental Quality; the Alliance
of Auto-mobile Manufacturers; Schram Auto Parts, a Michigan-based automotive
recycler; and Sustainable Research Group, a consultant. A larger steering
group that provided overall guidance to the study included representatives
from DaimlerChrysler, Ford, General Motors, Toyota, and the Ecology Center.
In addition, the Kalamazoo County Household Hazardous Waste program provided
assistance in the removal and recycling of the mercury pellets.
Convenience lighting was chosen for evaluation because it represents the
largest portion (greater than 85 percent) of the mercury found in vehicles.
Convenience light switches are located either under the
hood to illuminate the engine compartment or in the trunk to illuminate
the cargo storage area. Each switch assembly contains approximately 0.8
grams of mercury in a pellet (switch), which is normally constructed out
of steel. While the use of mercury in new vehicles has been substantially
reduced, the existing mercury in "end-of-life" vehicles could
be released into the environment if mercury convenience light switches
are not removed before the processed vehicle becomes feedstock for new
steel. If released to the environment, mercury emissions even-tally deposit
on land and water where the mercury can be converted into methylmercury,
a known neurotoxin, that bioaccumulates through the food chain.
The three-month study between the auto industry, dismantling industry,
and the MDEQ gathered information at ten Michigan automotive recycling
locations; recording the year, make, and model of vehicles entering recycling
facilities; whether or not they had mercury switches and, if so, then
documented switch assembly and mercury pellet removal methods and times.
The study also examined the barriers and challenges to removing mercury
switches. Overall, data was collected from 1,474 vehicles manufactured
between 1971 and 2003. Forty-four percent of vehicles were found to have
at least one switch present in either the hood or trunk. This equates
to 0.54 switches per vehicle. Of the pellets that were removed, 98 percent
contained mercury. It took an average of 51 seconds to remove the switch
assemblies, and an additional average of 44 seconds to remove the mercury
pellet from the assembly.
The switch study results are expected to be the basis for developing state
and local programs to remove mercury switches from "end-of-life"
scrapped vehicles. MDEQ plans to use the study to engage the various stakeholders
in a dialogue on how to best remove mercury found in Michigan vehicles.
The study did not include anti-lock brake system switches, nor did it
examine in-service mercury switch removal.