As I reported last week, Boulder, Lafayette and Fort Collins passed measures with solid margins to suspend or ban the technique formally known as hydraulic fracturing. But a fourth community, Broomfield, about 12 miles east of Boulder, narrowly rejected a fracking moratorium.

In Fort Collins, near the growing Niobrara field, 56 percent of voters approved a five-year ban on fracking, despite a resolution its city council passed urging voters to reject it.

"This election represents round one with many more rounds to come," said Tisha Schuller, president of the Colorado Oil and Gas Association, an industry group that opposed the measures. "Boulder and Lafayette were nothing more than symbolic votes. Lafayette's last new well permit was in the early 1990s and Boulder's last oil and gas well was plugged in 1999," she said.

The municipal bans may clash with fracking standards with the Colorado Oil and Gas Conservation Commission introduced this year that require wells to be located away from houses and established rules for noise, dust, and chemicals.