Folks who stayed up after Led Zeppelin’s interview and guest performance on the “Late Show with David Letterman” last night were treated to a short segment featuring the talented actor John Krasinski, known by most for his role as “Jim” on “The Office,” but now carving out some new credentials as the writer of the screenplay for “Promised Land,” a film in which he co-stars with the dreamy (notwithstanding that buzz-cut he’s currently sporting) Matt Damon.

Heretofore, the promotional activities associated with the soon-to-be-released movie have been pretty low-key – a few interviews with the film and entertainment rags, a Facebook post or two, a quick sit-down with The Today Show, and a fairly subdued online chat with the New York Times. And the funny thing is, for a movie that’s supposed to be some sort of polemic about “hydraulic fracturing,” that topic really hasn’t come up a whole lot yet as part of the interviews they’ve done. Indeed, Krasinski (and Damon too) continue to go to great lengths to assure us that this film isn’t about hydraulic fracturing at all – insisting instead that it’s a story about “American identity,” which we assume is something really profound that only folks in Hollywood would fully understand.

Anyway, Krasinski’s interview with Letterman was going along just fine last night – lots of talk about how Led Zeppelin’s the greatest band ever (we agree); good bit of chatter about how Krasinski’s career has really taken off; some friendly banter about how gorgeous Matt Damon is, the usual stuff. But then the topic turned to hydraulic fracturing, and, as sometimes they do on Letterman, things turned really silly really quickly from there – with Letterman querying whether he could ask the decidedly non-technical Krasinski “a technical question” about hydraulic fracturing, leading to a two-minute, fact-free explanation of a process about which neither participant proved to have any real, actual, discernible knowledge.

So then: since it can be assumed that John Krasinski will be doing more of these promotional interviews in the weeks and months to come – and likely will be fielding additional questions about what hydraulic fracturing is, how it’s done, and how it’s regulated – here below, a quick “cheat sheet” with information on everything he talked about last night … so that next time, he can get it right.

Krasinski: Hydraulic fracturing is “drilling into shale deposits rather than oil deposits.”

• First of all, hydraulic fracturing is not a drilling technique. When companies want to develop oil and natural gas from shale, and after they have conducted all of the preliminary geologic monitoring and testing, they drill down to what’s known as the target formation, which is the geologic area from which they will be producing oil or natural gas. For hydraulic fracturing to occur, however, the drilling equipment must first leave the well pad. Trucks and other equipment enter the well pad after the drilling rig has left, and then the process of hydraulic fracturing can commence. So when Krasinski says of hydraulic fracturing: “basically it’s just a long drill,” that’s clearly not the case.

• As the director of Indiana’s Department of Natural Resources, Herschel McDivitt, has said: “Remember that drilling is drilling, well construction is well construction…producing is producing, and fracing is fracing.”

• Secondly, a shale deposit and an oil deposit are not mutually exclusive things. Indeed, the massive Bakken oil field in North Dakota and large parts of the Eagle Ford shale in south Texas, for example, are oil deposits. Shale and other “tight” reservoirs are the source rock for oil and natural gas, and the fact that the industry can produce from these formations is proof that they are, in fact, oil and natural gas deposits. After all, the oil and natural gas produced from shale formations is no different than the oil and natural gas produced in what some call “conventional” wells – deposits that don’t need added stimulation like hydraulic fracturing.

Letterman: “Now let me ask you a technical question. There is the ‘deep fracking’ that you go deep, and then, and then, horizontal – and then there is the more shallow version of it. … And it’s my understanding that the more shallow version of it is the more dangerous – the more …”

Krasinski: “Yes. Because it’s releasing gases, um, they’re not able to trap it as much, um, it’s coming right through the ground.”

• Whether the well is shallow or deep, the fracturing process really doesn’t change a whole lot. Sure, the volume of pressure and water needed may differ, with deeper wells requiring more and shallower ones less, but the basic mechanics of a fracturing operation don’t change based on depth: no matter how you slice it, it’s about delivering water, sand and pressure downhole, to create millimeter-sized conduits in rock for hydrocarbons to access the wellbore. Some folks would like you to believe that shale “fracking” is different from conventional stimulation – so that they can convince you that the former is more dangerous than the latter, or maybe the other way around? We don’t remember. But it’s not.

• Of course, shallow or deep, hydraulic fracturing has been applied more than 1.2 million times since 1947, and there is not a single confirmed case of water contamination. How do we know that? Well, for one, the U.S. Environmental Protection Agency – under three separate administrations – has said so. Here’s what Lisa Jackson, current EPA administrator, said earlier this year: “In no case have we made a definitive determination that [hydraulic fracturing] has caused chemicals to enter groundwater.” That’s one heck of a record.

• We’re not really sure what Krasinski means when he says “it’s releasing gases” and that the industry can’t “trap it as much,” though – we think he may just be free-styling there. What he may be referring to, however, is the fact that shallow geologic formations often contain deposits of methane. These are also often the same deposits that have naturally entered into water wells, a phenomenon that has been documented for centuries. In many parts of Pennsylvania, for example, methane bubbles to the surface in small rivers and creeks – all due to natural processes. What the industry usually targets for shale development, however, are formations a mile or more below groundwater supplies, and obviously much further from the surface.

Letterman: “And chemicals are used to blow it back out of the shale.”

Krasinski: “Correct.”

Letterman: “And chemicals which not necessarily need to be identified …”

Krasinski: “Ahhhh, who needs that?”

Letterman: “So. And a provision removed from the EPA Clean Water bill …”

Krasinski: “You’ve done your homework …”

Letterman: “So these oil companies and go ahead and use whatever they want. And would only have to reveal what was in there if there was a problem.”

• Oof. Unfortuantely, there’s clearly much more homework to be done here!

• Regarding the claim that the chemicals don’t need to be identified, that’s not true. States across the country have mandatory disclosure laws on the books, and other states are moving forward with similar such laws, typically with the support of the industry. Many operators, however, already use FracFocus.org, which is an online database of the additives used during hydraulic fracturing. Visitors to that site can search on a well-by-well basis to discover what is and isn’t in the specific fracturing fluid used at a particular well site.

• FracFocus has been highly praised, too. For example, here’s how President Obama’s energy and climate change advisor Heather Zichal described it: “As an administration, we believe that FracFocus is an important tool that provides transparency to the American people.”

• Also, the “EPA Clean Water bill” (which is actually the Safe Drinking Water Act) was amended in 2005 to affirm that the strong regulatory regime already in place at the state level – which the current EPA has applauded for doing a “good job” of protecting the environment – should remain the primary means of regulation for hydraulic fracturing. Nothing was “removed” from SDWA, which has been the law of the land for nearly forty years – and, by the way, was never designed to cover hydraulic fracturing.

Letterman: “And that’s where we see the stories of … ‘er, turn on the water, ma’ … whoosh. And you know, the sink explodes.”

Krasinski: “Yeah. Gives new meaning to ‘fire water.’”

• Flaming water? We can only guess this is coming from that emblematic scene in Gasland where a Weld County, Colorado man lights his tap water on fire.

• What did that film leave out? Well, Colorado regulators were interested in that incident and decided to investigate. They even released a fact sheet in response to the film. Those same regulators said this particular case “was not related to oil and gas activity,” but rather a result of what’s known as biogenic methane – that is, methane that occurs naturally in groundwater.

Letterman: “But the thing about the film. I know it happens. There are towns in the north and the west where people are divided. Because some towns are in desperate economic need. And some towns want to preserve the culture that they like about their hometown.”

Krasinski: “100 percent.”

• The great news here is that shale development is not a barrier to towns who want to “preserve the culture that they like about their hometown.” In fact, the small businesses that populate Main Street in towns across the country are often some of the biggest beneficiaries of shale development. People who work for the industry need places to eat, apartments to sleep in, and other stores to do their shopping. These workers are also members of the community, and they like to support local businesses just as much as their fellow citizens.

• But the bigger point here is that the “division” between economic benefits and environmental protection is one that has been invented by opponents of development. Yes, there are risks inherent with all forms of energy. And residents have a right to ask questions and demand answers – based in fact – about what the impacts may or may not be in their communities. The industry frequently holds open forums and information sessions in towns across the country to engage in this dialogue and address concerns.

• What opponents have done, however, is undermine that good faith discussion by trying to convince landowners that the industry is only looking out for “profits” and will pollute the water, cause earthquakes, and countless other problems. They have lodged accusations designed to secure headlines, and tragically, they have been very successful.

• The reality is that shale development is done under tight regulatory regimes in every state, and higher operating standards help ensure that these processes are done efficiently and responsibly.

• That means we don’t have to pick between a healthy environment and strong local economies, though we also acknowledge that the best Hollywood movies are based on conflict, not harmony – even if that conflict has been largely manufactured.