Cash for Clunkers' footprint

by Erin Wayman
Thursday, January 5, 2012

In August, the Wall Street Journal reported that a little-known chemical was playing a big role in the Cash for Clunkers program. The federal government required dealerships to pour sodium silicate, or liquid glass, into the engines of the traded-in clunkers. The solution destroys the engine, ensuring that the old cars and trucks never end up back on the road. The Journal noted that chemical companies couldn’t keep up with the sodium silicate orders that were pouring in. The demand was so high that liquid glass became the “best-selling product of the year,” Robert Mueller, owner of a chemical company in Illinois, told the newspaper.

But the surge in sodium silicate orders did not have much effect on the minerals that make up the chemical, says Joyce Ober, a mineral commodity specialist at the U.S. Geological Survey in Reston, Va. Sodium silicate consists of soda ash, or sodium carbonate, and high purity silica sand. Ober calculated how much sodium silicate would be needed to retire 750,000 cars (about 690,000 clunkers were traded in). Based on that number, she determined the amount of sodium silicate required to destroy those engines would have used only about 0.003 percent of the 11 million metric tons of soda ash produced annually and 0.002 percent of the high purity silica sand produced each year. Thus, Cash for Clunkers “didn’t create a new demand” for these minerals, Ober says. But it did give sodium silicate its 15 minutes of fame.

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