Late Show host David Letterman went on an epic anti-fracking rant Wednesday evening, calling out "greedy oil and gas companies" for "injecting highly toxic and carcinogenic chemicals" into the ground.

He's the latest celebrity to take issue with the boom in hydraulic fracturing that's been used to extract hydrocarbons from shale rock. Recently, John Lennon's widow Yoko Ono and son Sean Lennon went on "Late Night With Jimmy Fallon" to promote their site ArtistsAgainstFracking.com.

Studies showing the effects of fracking remain highly contentious and somewhat inconclusive.

Watch Letterman's rant below:

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