The video showed a drill bit cutting through a blue aquifer at '3001,000 feet' and then descending down to a gas reservoir at '5,00013,000 feet.'

'Additionally, steel pipes, called casing, cemented in place, provide a multi-layered barrier to protect fresh-water aquifers.'

Book raised his hand, as if he were back in third grade. Billy Bob paused the video and raised his eyebrows.

'Yes, Professor?'

'Steel and cement casing,' Book said. 'Isn't that what they had on that offsh.o.r.e rig that blew out, spilled millions of gallons of crude oil in the Gulf of Mexico?'

'What they had were idiots making decisions.'

Billy Bob clicked the remote and resumed the video.

'During the past sixty years, the oil and gas industry has conducted fracture stimulations in over one million wells worldwide. The initial steps are the same as for any conventional well. A hole is drilled straight down using fresh-water-based fluid, which cools the drill bit, carries the rock cuttings back to the surface, and stabilizes the wall of the well bore. Once the hole extends below the deepest fresh-water aquifer, the drill pipe is removed and replaced with steel pipe, called surface casing. Next, cement is pumped down the casing. When it reaches the bottom, it is pumped down and then back up between the casing and the bore hole wall, creating an impermeable additional protective barrier between the well bore and any fresh-water sources.'

Book raised his hand again. Billy Bob paused the video again.

'Impermeable?' Book said. 'Cement sidewalks crack over time, why not cement casings? Can you guarantee no leakage?'

'Industry guidelines only require no significant leakage.'

'Significant? What does that mean?'

'More than insignificant.'

Billy Bob restarted the video.

'What makes drilling for hydrocarbons in a shale formation unique is the necessity to drill horizontally. Vertical drilling continues to a depth called the "kickoff point." This is where the well bore begins curving to become horizontal.'

The animation showed the drill bit slowly turning to a ninety-degree course through the earth.

'When the targeted distance is reached, the drill pipe is removed and additional steel casing is inserted through the full length of the well bore. Once again, the casing is cemented in place. Once the drilling is finished and the final casing has been installed, the drilling rig is removed and preparations are made for the next steps: well completion. The first step in completing a well is the creation of a connection between the final casing and the reservoir rock. This consists of lowering a specialized tool called a perforating gun, which is equipped with shaped explosive charges, down to the rock layer containing oil or natural gas. This perforating gun is then fired, which creates holes through the casing, cement, and into the target rock. These perforating holes connect the reservoir and the well bore. Since these perforations are only a few inches long and are performed more than a mile underground, the entire process is imperceptible on the surface.'

Book held up a hand. Billy Bob exhaled then stopped the video.

'You're setting off explosive charges inside the earth?'

'Same thing they do in mining.'

'I read something about fracking causing earthquakes.'

Billy Bob snorted. 'Minor earthquakes.'

He resumed the video.

'The perforation gun is then removed in preparation for the next step: hydraulic fracturing. The process consists of pumping a mixture of mostly water ...'

Book raised a finger; he felt almost apologetic. Billy Bob paused the video.

'How much water?'

'Five million gallons.'

'Per well?'

'Yep.'

'What's your source?'

'Aquifer.'

'That's drinking water.'

'Not after I use it to fracture a well.'

'Lot of water.'

'Lot of gas. But actually, Professor, it's not that much water because it's a one-time usage with fracturing. A regulation golf course uses five million gallons of water every month. And we only use two gallons of water per million BTUs. Ethanol production uses twenty-five hundred gallons to produce the same amount of energy.' Another snort of disgust. 'What a joke that is. And Bush gave 'em the ethanol tax break. Now every farmer in America is growing corn for the ethanol plants.'

He restarted the video.

'... and sand plus a few chemicals ...'

Nadine shot her hand into the air and waved it like Ms. Garza wanting attention. Billy Bob paused the video and regarded her.

'You too, Honeywell?'

'What chemicals?'

'Same stuff you find under your kitchen sink.'

'Like Drano?'

'You want your kids drinking frack fluids?' Book said.

'Maybe, but the little b.a.s.t.a.r.ds live in Houston with their mother. My first ex. Second ex, she lives in Dallas. Third, she got my house in Aspen. G.o.dd.a.m.n community property laws. You'd think I'd learn about women.'

'Or they'd learn about you.'

'Hey, they did just fine by me.'

Almost as if he were bragging about how much he had lost in his divorces.

'But not to worry, Professor, we're not contaminating the groundwater. The chemicals we use, they're harmless. Watch.'

He restarted the video. On the screen a list of chemicals came up. Book read the list aloud.

'Chloride.'

'Table salt,' Billy Bob said.

'Polyacrylamide.'

'In contact lenses.'

'Ethylene glycol.'

'Household cleaners.'

'Sodium and pota.s.sium carbonate.'

'Laundry detergent.'

'Glutaraldehyde.'

'Disinfectant.'

'Guar gum.'

'Ice cream.'

'Citric acid.'

'Sodas, ice cream, cosmetics.'

'Isopropanol.'

'Deodorant.'

Billy Bob turned his hands up as if innocent of all charges.

'See, Professor, that's just regular stuff. We ain't putting diesel fuel down the hole anymore.'

'You used to?'

'Back in the day. But the Environmental Protection Agency banned diesel in slick water back in oh-five.'

'Slick water? Is that the same as frack fluid?'

'We don't say frack, so we call it slick water.'

'I guess that does sound better than "toxic brew" or "chemical c.o.c.ktail."'

'Much.'

'... under controlled conditions into deep underground reservoir formations. The chemicals are generally for lubrication, to keep bacteria from forming, and help carry the sand. These chemicals typically range in concentration from zero-point-one to zero-point-five percent by volume ...'

Book raised his hand; Billy Bob sighed and stopped the video.

'd.a.m.n, Professor, I wouldn't want to go to a movie show with you.'

'One-half percent of five million gallons is still, what-'

'Twenty-five thousand gallons,' Nadine said Book and Billy Bob both cut their eyes to her. She shrugged.

'I'm good with numbers.'

Book turned back to Billy Bob. 'Twenty-five thousand gallons of toxic chemicals pumped down into the earth? In each well?'

'Can we watch the video? This is the good part.'

Billy Bob pointed the remote, and the animation went into action.

'... and help to improve the performance of the stimulation. This stimulation fluid is sent to trucks that pump the fluid into the well bore and out through the perforations that were noted earlier. This process creates fractures in the oil and gas reservoir rock. The sand in the frack fluid-'

Nadine gave a fake gasp. 'OMG-he said frack.'

Billy Bob shook his head as if exasperated with a child.

'-remains in these fractures in the rock and keeps them open when the pump pressure is relieved. This allows the previously trapped oil or natural gas to flow to the well bore more easily. This initial stimulation segment is then isolated with a specially designed plug and the perforating guns are used to perforate the next stage. This stage is then hydraulically fractured in the same manner. This process is repeated along the entire horizontal section of the well, which can extend several miles. Once the stimulation is complete, the isolation plugs are drilled out and production begins. Initially water, and then natural gas or oil, flows into the horizontal casing and up the well bore. In the course of initial production of the well, approximately fifteen to fifty percent of the fracturing fluid is recovered.'

Book raised his hand. Billy Bob stopped the video.

'So only fifteen to fifty percent of five million gallons-'

He glanced at Nadine.

'Seven hundred fifty thousand to two-and-a-half million gallons.'

'-is recovered. Which means at least fifty percent of those chemicals-'

'Twelve thousand five hundred gallons.'

'-and maybe as much as eighty-five percent-'

'Twenty-one thousand two hundred fifty gallons.'

'-isn't recovered. What happens to all those chemicals?'

Billy Bob shrugged. 'They stay in the reservoir. There's five to ten thousand feet of rock between the gas formation and the aquifer, Professor. Fluids can't migrate through a mile or two of rock. That's why they call it rock. Those chemicals ain't going anywhere.'

'You sure?'

'Pretty sure.'

Billy Bob restarted the video.

'This fluid is either recycled to be used on other fracturing operations or safely disposed of according to government regulations.'