The automotive industry seemingly would be a distant thought for anyone perched atop one of Michigan's majestic lakeshore sand dunes. But that's not the case for a few lawmakers, environmentalists and foundry workers.

Dune sand is mined and used to cast auto parts, such as crankshafts, transmission gears and cylinder heads — a practice two Michigan legislators aim to halt by 2006.

The proposal so far has lacked support in the Michigan legislature and expired at the end of 2000. But the bill's sponsors hardly feel vanquished. “We'll reintroduce it again (in 2001),” says state Rep. Julie Dennis of Muskegon, who co-sponsored the proposal with fellow Democrat state Sen. Gary Peters of West Bloomfield Twp. “It's sparked some interest, especially among representatives who have sand dunes in their district and want to preserve them.”

Dune sand is favored over inland sand by some foundry operations because it is cleaner and has a uniform rounded shape and high silica content.

Michigan has the world's largest collection of freshwater dunes, and environmentalists say dune mining is destroying an irreplaceable resource. The legislation calls for a complete ban on dune mining by 2006.

On the other side, “Enactment of this legislation could force GM to cease manufacturing a significant number of iron castings,” says Mike Williams, components manufacturing manager at General Motors Corp.'s Powertrain unit.

Or it could force automakers to look elsewhere for sand. Ford Motor Co. owns the only known adequate site for inland sand in Michigan. But that site couldn't support the entire industry for long. There also are sites available for mining in Ohio, Wyoming, Australia and elsewhere. But that solution requires an increase in retrieval and transportation expenses and higher processing costs to remove the silt and other impurities commonly found in non-dune sand. And in some cases, alternative locations provide sand that can be used in only highly specific applications because of its composition. Oceanside dunes usually aren't an option because salt water is detrimental to casting.

Of the traditional Big Three auto-makers, GM is the most reliant on dune sand. Its operations in Defiance, OH, Saginaw, MI, and Massena, NY, use dune sand. So does Ford's Windsor, Ont., engine facility. “We are studying alternatives now for Windsor,” says John Counihan, a supervisor of process improvement at Ford.

DaimlerChrysler Corp. claims it doesn't use dune sand, but acknowledges some of its suppliers do. Ford began switching from dune sand to inland sand in the 1970s. Currently, about 25% of the sand Ford uses comes from dunes. The rest is from inland deposits.

Opponents of the bill say partsmakers would be in a pinch to meet the 2006 deadline. “A complete ban is unacceptable,” says Bill Lievense of the Foundry Assn. of Michigan.

Even Ms. Dennis concedes a total ban is unlikely. But she hopes to close some loopholes. For example, lowering the maximum time for mining without a permit and reducing the amount of Michigan dune sand shipped to out-of-state foundries. Ms. Dennis notes only 30% of Michigan dune sand stays in the state.

Opponents say that there is enough regulation and there are bigger contributors to sand dune erosion than mining, such as commercial developments. They also note that some industries are able to recycle sand for applications after automakers have used it 20 to 30 times for castings. And an interesting solution developed by GM may broaden recycling efforts. It's contracted Hormel Foods Corp. to make a binding agent from animal protein. The product, called GMBond, will replace the toxic chemicals currently used to bind sand to create molds, making for easily recycled sand.

GM's process could lessen the environmental impact, which opponents of the bill say already is minimal. Only 1,500 of Michigan's 275,000 acres of dunes are licensed for mining. But those 1,500 acres are very productive. In 1999, 2.8 million tons of sand were mined from Michigan dunes. Since 1978, some 50 million tons of dune sand have been removed. The mining has completely leveled some dunes and, critics say, disrupted the water table. “We're keenly aware of the sensitivity of using it,” says Mr. Lievense. “That's why we're so responsible.”