Environmentalists are concerned drilling for new sources of natural gas in Michigan could contaminate water. They're basing that on reports from other states that blame a new method of drilling for contaminating their water.
This new kind of drilling is called horizontal hydraulic fracturing. Until recently in Michigan, it was only used in vertical wells. Drill down, pump water, sand and chemicals at high pressure into a layer of shale, fracture it and release the natural gas trapped there.