DENVER—Chances are minimal of radioactivity being released if a natural gas well is drilled near the site of an old underground nuclear blast in western Colorado, a new federal study says.
The Department of Energy’s report, released Wednesday, comes as companies are drilling closer to Project Rulison, where a nuclear weapon was detonated 8,426 feet below the surface in 1969 to free up gas.
Two years ago, a company proposed drilling within a half-mile state buffer around the site, which triggers an automatic hearing. The company backed out after Garfield County and residents raised concerns.
No applications are pending to drill within the buffer now, but the area is in the heart of western Colorado’s energy boom.
Nearby landowners and residents fear that drilling near the site could release contamination, possibly harming groundwater and streams that feed into the Colorado River.
Luke Danielson, an attorney representing three families opposed to drilling within the buffer, said the DOE report was based on a mathematical model rather than data.
He also questioned the timing of the release of the study, about two weeks before Colorado regulators hold a public hearing on the Rulison site. “It has all the appearances of being a very political act,” he said.
Tom Pauling of DOE’s Office of Legacy Management in Grand Junction said no radioactive contamination above naturally occurring levels reached the gas well in 95 percent of the computer simulations in the study.
In the other 5 percent, the radioactivity was extremely low, Pauling said.
The study focused on tritium because it is the radioactive byproduct most likely to migrate.
“Based on the mathematical model, it’s very unlikely for tritium to migrate to a production well based on the current restrictions,” Pauling said.
The report’s conclusions are also based on years of monitoring the site. Although federal officials “can’t know everything about the subsurface,” Pauling said they are confident the study was thorough.
“But we think there’s room to raise questions,” Pauling added. “We don’t propose resting entirely on this study.”
The DOE is discussing the report with state oil and gas regulators and health officials. The Colorado Oil and Gas Conservation Commission, a regulatory body, has scheduled an Oct. 2 public hearing in Grand Junction to discuss the Rulison site.
Rulison, about 190 miles west of Denver, was part of the federal government’s Plowshare Project, which sought peaceful uses for nuclear devices. The former Atomic Energy Commission detonated the 43-kiloton bomb to free gas in the Williams Fork Formation.
A well drilled by DOE produced gas, but it was considered too radioactive to be sold commercially. The agency began deactivating and cleaning the area in the 1970s.
Long-term management of the blast site was recently turned over to the DOE’s Office of Legacy Management, but the state approves drilling permits.
The federal government prohibits drilling below 6,000 feet within a 40-acre zone around the blast site. The state oil and gas commission has set boundaries that trigger more scrutiny but no outright bans. The commission notifies the DOE when a company wants to drill within a three-mile radius of the site.
DOE has said most of the radioactivity from the 1969 explosion was trapped in a glass dome formed when melted and vaporized rock collected in a puddle with a diameter of about 160 feet and cooled.
