"Gasland II" (9 p.m., HBO) continues filmmaker Josh Fox's efforts to alert viewers to the dangers of hydraulic fracturing, popularly known as "fracking." The process has been touted as a means to cheap fuel, energy independence and economic development. Fox begins "Gasland II" with audio clips praising gas drilling from the likes of President Barack Obama and Bill and Hillary Clinton.

As in his first film, Fox visits farmers, ranchers and homeowners whose lives and properties have been left worthless by contaminated water supplies. Beyond these anecdotes, Fox paints a chilling portrait of state governments cooperating with gas companies to harass and demonize opponents of gas drilling, even calling some "terrorists."

A metaphor of warfare pervades the film and the fight over fracking. Fox presents evidence of gas companies hiring military psychological-warfare experts as part of their political outreach campaign. These veterans of Iraq and Afghanistan suggest that domestic anti-fracking activists be treated as "insurgents."

Arguably, the most powerful figure in Fox's film is Tony Ingraffea, a Cornell professor of engineering, with long experience in the gas industry. He offers evidence, backed up by ample industry research, that fracking can never be done safely. The process requires cement casings around the drilling pipes to keep natural gas from escaping into water supplies, wells and aquifers. Citing the gas industry's own research, Ingraffea shows that one in 20 cement casings fail immediately, and that many more break down over time. With tens of thousands of wells being sunk, even that five percent rate presents a threat to the nation's water supply. Safe fracking, he says, is simply a myth.

And to spread that myth, the gas industry has spent a fortune, even hiring the same PR firm that big tobacco used in the 1950s and '60s to argue that cigarettes were safe and did not cause cancer.

I wish there were more experts like Ingraffea in "Gasland II" and fewer shots of Fox hunting and banjo playing. His films have made Fox a minor celebrity, and many reasonable people resent serious policy being discussed or set by Hollywood stars. That quibble aside, "Gasland" and its sequel show how the documentary film has become one of the most powerful tools to debate and shape public policy, perhaps earning it a place in history alongside Ralph Nader's "Unsafe at Any Speed" and Rachel Carson's "Silent Spring."


---Antiques Roadshow" (9 p.m., PBS) visits Rochester, N.Y.

---Daphne undergoes a cochlear implant on "Switched at Birth" (8 p.m., ABC Family, TV-14).

---NBC hires a former Discovery channel star to host "Get Out Alive With Bear Grylls" (9 p.m., NBC).

---An awkward dinner on "The Fosters" (9 p.m., ABC Family, TV-14).

---Election Day on "Defiance" (9 p.m., Syfy, TV-14).

---A botched drug bust on "Major Crimes" (9 p.m., TNT, TV-14).

---Big Jim needs help on "Under the Dome" (10 p.m., CBS, TV-14).

---Keeping it unreal on "Siberia" (10 p.m., NBC, TV-14).

---The "POV" (10 p.m., PBS) presentation "Herman's House" explores art and redemption.

---An alchemist dissolves into obscurity on "Warehouse 13" (10 p.m., Syfy, TV-14).

---A husband hires a hit man on "Longmire" (10 p.m., A&E, TV-14).

---A used car dealer lays it on rather thick in the new series "God, Guns & Automobiles" (10 p.m., History).


---Underachievers (John Cusack, Rob Corddry and Craig Robinson) return to 1986 in the 2010 comedy "Hot Tub Time Machine" (9 p.m., Comedy Central).


---"The Daily Show" and "Colbert" are pre-empted this week.

---Armie Hammer, Angie Harmon and Brent Morin appear on "Conan" (11 p.m., TBS).

---Michael Cera appears on "Late Show With David Letterman" (11:35 p.m., CBS).

---Jay Leno welcomes Charlie Day, Jeffrey Dean Morgan and Lionel Richie on "The Tonight Show" (11:35 p.m., NBC).

---Mary-Louise Parker, Idris Elba and Rhye appear on "Jimmy Kimmel Live" (11:35 p.m., ABC).

---Craig Ferguson hosts Heather Locklear and Louie Anderson on "The Late Late Show" (12:35 a.m., CBS).

(Kevin McDonough can be reached at kevin.tvguygmail.com.)