In the past six years, the number of earthquakes has skyrocketed. For decades, the U.S. averaged 21 earthquakes, of magnitude 3.0 or higher, a year magnitude. Between 2009 and 2013, the average rose to 99 and reached a whopping 659 in 2014.

The University of Colorado Boulder and Stanford University each released a study June 19 looking for answers. Both point to wastewater injection.

“The entire rate change that we’ve seen in the last few years is associated with injection wells,” said Matthew Weingarten, who led the CU-Boulder study, to Christian Science Monitor. “We think that’s clear evidence that this earthquake rate of change is not natural.”

Between Colorado and the North Atlantic, Weingarten’s team found 18,757 wells that potentially influenced earthquakes. Their study, published in Science, looked at both saltwater disposal wells and enhanced oil recovery wells.

The U.S. Geological Survey long ago established that fluid injection causes earthquakes by pressurizing and lubricating faults. Wastewater wells operate longer and inject far more fluid than hydraulic fracturing or enhanced oil recovery wells — where injected water, steam and carbon dioxide improve oil and gas extraction — making wastewater the most common earthquake causing wells. Most of the what’s forced back into the Earth is “produced” water, salty and chemical laden fluid that flows out of nearly all oil and gas wells. Hydraulic fracturing fluid typically makes up less than 10 percent of injected wastewater.

— Mollie Putzig


With rain finally tapering off and temperatures in the mid-80s, a study published May 20 in JAMA Dermatology sheds light on policies protecting outdoor workers from the Colorado sun.

Researchers from Klein Buendel Inc. in Golden looked into sun-safety policies of 98 local government organizations across Colorado. Some suggest sunglasses, others hats, clothing or sunscreen, but of the policies examined, a vast minority specifically state the purpose of protecting workers.

“Outdoor workers are at increased risk for skin cancer because of long-term exposure to solar UV radiation,” the study reads. “Although organizational policies have the potential to increase sun protection in occupational settings, occupational sun-safety policies were uncommon among local governments.”

The study found 87 percent of policies mention sun protection in at least some form, though measures requiring sun protection for employees were rare.

Construction workers are six times more likely to develop skin cancer than the general public, according to the American Cancer Society.

“Opportunities exist for dermatologists and other physicians to influence occupational sun-safety practices and policies, which are consistent with other safety procedures and could easily be integrated into existing workplace practices,” the study concludes.

— Mollie Putzig