Last week, 13 workers were exposed to a radiation leak at the Waste Isolation Pilot Plant (WIPP) near Carlsbad, New Mexico. WIPP is one of the world’s three deep geological repositories licensed to permanently dispose of radioactive waste.

More workers who were present at the facility the day following the leak will be tested for contamination. According to the Wall Street Journal, the US Department of Energy is still trying to determine the cause of the leak. The agency said Monday that workers were exposed to americium, a transuranic radioactive chemical from nuclear weapon production.

At a news conference on Thursday, officials said radiation levels around the site are below levels that would require notifying the Environmental Protection Agency. Tests revealed that radiation had escaped the facility, but reportedly only at low levels.

WIPP is the only facility in the United States created to permanently store radioactive waste. The facility has been storing waste from research and production of nuclear weapons since 1999. The government contractor that runs the plant, Nuclear Waste Partnership LLC, is asking employees to submit samples for testing.

In the United States, Energy Secretary Ernest Moniz is a proponent of nuclear energy, as well as hydraulic fracturing. Even the deadly Fukushima disaster in 2010 sparked little response from US policy makers. After Fukushima, Moniz released a report entitled “Why We Still Need Nuclear Power,” which says that abandoning nuclear power would be a mistake.

Despite the ongoing Fukushima disaster, the World Nuclear Association has predicted a 30 percent increase in global nuclear generating capacity over the next ten years.

Alisha is a writer and researcher with Ring of Fire. You can follow her on Twitter @childoftheearth.