Under pressure from Coloradans, the government has launched a review of radon emission standards at uranium-processing facilities.
Environmental Protection Agency officials in Denver last week said they’ll reassess health risks and consider tightening the national standard set two decades ago.
Radon wafting from uranium tailings “has the potential to cause lung cancer,” said Angelique Diaz, an EPA environmental engineer specializing in radiation.
An EPA group in Washington launched the review after complaints from Colorado activists concerned about a spike in radon emissions at a former uranium mill near Cañon City.
A review of standards required under the Clean Air Act had been neglected, federal officials said before a hearing in Cañon City last week. More hearings are planned in South Dakota and Utah before a decision is made.
In Colorado, the latest data that mill operator Cotter Corp. provided to state and federal regulators indicated that radon emissions from toxic tailings last year nearly reached the maximum allowable 20 picocuries — a measurement of radioactivity — per square meter per second. That reflects a surge from about 6 picocuries in 2006 — an increase attributed to a state-mandated project to dry out ponds that covered toxic tailings leaking into groundwater.
Violations during cleanup
Superfund cleanup of the Cotter uranium mill, located just south of Cañon City, population 15,850, has lagged after repeated violations with toxic tailings leaching into groundwater. The “dewatering” of impoundment ponds at the shuttered mill, intended to stop the contamination of groundwater, leaves the toxic tailings increasingly exposed to the air.
A naturally occurring radioactive gas, radon tends to glom onto dust. Radon occurs naturally in uranium-rich areas. EPA and Nuclear Regulatory Commission authorities regulate radon because of the risk of ingestion, which can cause cancer.
Inside homes, the EPA recommends “mitigation” — which usually means better ventilation — if radon concentrations top 4 picocuries per square meter per second.
But this situation involves the air around industrial facilities.
While the Cañon City mill officially remains an environmental disaster, owner General Atomics is pursuing a plan to reopen for nuclear business by hauling 12.5 million tons of ore by train from a protected mountain in New Mexico to refurbished facilities here along the Arkansas River.
Cotter executives have informed state officials they will crush and chemically leach 500,000 tons of uranium per year for 25 years — starting as soon as 2014 — “dependent upon market forces.”
Fremont County commissioners are pushing for cleanup completion and possible decommissioning of the mill.
“They haven’t done another cancer study since they finished one in 1995, and that is what is driving our work,” said Sharyn Cunningham, a leader of Colorado Citizens Against Toxic Waste — one of two groups that filed complaints about rising emissions.
“Our concern is that these particles are very fine. They blow in the wind. . . . The closest neighborhood is one-quarter mile away, and the golf course is right next door. The population is too close to this facility,” Cunningham said.
“Uncertainty on the risk”
Air-testing for radon is done at the mill once a year. Results from the recently completed 2009 test are not expected to be released until March, citizens said.
Frequent testing seems sensible, Cunningham said, because radon emissions in 2008 nearly cracked the limit.
When the EPA set the 20 picocuries standard in 1989, some federal experts favored a stricter standard of 2 picocuries, according to federal documents.
“We may have had comment at that time about a different number,” said Chris McKenney, the Nuclear Regulatory Commission’s chief of performance assessment. That reflects scientific uncertainty about health effects, he said. “Radon has a very large uncertainty on the risk.”
Commission officials said air-testing ought to include readings taken beyond facilities, in areas where people live.
“What’s most important is the radon concentrations in the town,” said Myron Fliegel, the commission’s senior project manager for uranium recovery licensing.
Colorado health officials have taken the lead in supervising cleanup at the Cotter site.
EPA overseers still regard the 20 picocuries limit as protective, “and Cotter is currently below the standard,” Diaz said. “I’m not aware of any air monitoring that EPA does in the town.”
Bruce Finley: 303-954-1700 or bfinley@denverpost.com
