At 6:40 in the morning, a klaxon horn sounds three times. Gas! a man in a hard hat and fluorescent vest yells out. Theres a hissing noise, and the helium starts flowing. From the tanks stacked like cordwood on a nearby truck, the gas moves through a series of hoses until its 55 feet up, then through a copper pipe and into the top of a plastic tube that hangs down to the ground, like a shed snake skin held up for inspection.