Colorado Gov. John Hickenlooper went to unusually great lengths to learn firsthand the strides the oil and gas industry has made to minimize environmental harm from fracking.

The first-term Democrat and former Denver mayor told a Senate committee on Tuesday that he actually drank a glass of fracking fluid produced by oilfield services giant Halliburton.

The fluid is made entirely “of ingredients sourced from the food industry,” the company says, making it safe for Mr. Hickenlooper and others to imbibe.