Colorado says mine can continue polluting creek above a Denver drinking water reservoir
Colorado health officials have granted Climax Molybdenum a third extension of a “temporary” lifting of the state’s health limit for molybdenum pollution of a creek, allowing continued elevated discharges above Denver’s drinking water supplies.
The Colorado Department of Public Health and Environment water-quality commissioners voted unanimously this week to give Climax until June 2020 to meet state standards.
The delay, commissioners said, will give time for Climax to resolve scientific uncertainty around how much molybdenum is too much for people. They also said Climax must use the extra time to work toward reducing the pollution of Ten Mile Creek to acceptable levels.
“CDPHE expects Climax will make progress on, and adhere to, the plan to resolve uncertainty … as well as follow the commission’s direction … to investigate molybdenum sources and treatment alternatives,” according to a statement that an agency spokesman said could be attributed to the agency’s water-quality standards manager Blake Beyea.
Climax has been lobbying the CDPHE to relax the statewide limit for molybdenum pollution of waterways, which would ease the company’s wastewater-cleaning burden. Climax has submitted industry-backed studies, not yet fully reviewed, supporting a loosening of Colorado’s limits to 9,000 parts per billion from 210 ppb for streams used to supply drinking water, and to 1,000 ppb from 160 ppb for streams used for irrigating pastures and food crops.
Climax Molybdenum, a subsidiary of the $46 billion global mining company Freeport-McMoRan, runs the open-pit Climax Mine in high-altitude tundra above Dillon Reservoir on Fremont Pass, between Frisco and Leadville, employing about 400 workers. Molybdenum is used to harden steel and for petroleum-industry lubricants. An existing water treatment plant below the mine removes many contaminants, though not molybdenum. Removing all molybdenum from mining discharges could cost hundreds of million of dollars — either for Climax or for Denver Water and the 1.4 million metro residents it supplies.
Denver Water officials and downstream communities concerned about the contamination — CDPHE officials have said they’re aware of molybdenum spikes at up to 3,000 ppb – accepted giving Climax more time with the understanding that Climax would work to reduce the pollution.
CDPHE commissioners granted this third extension of their temporary 2014 lifting of the 210 ppb limit yet also will provide “more substance and details on what Climax must do during the delay,” said Steve Bushong, an attorney for a group of communities and agricultural water users.
Colorado residents and state health scientists “wanted to make sure progress was being made on identifying the source of the large molybdenum spikes and identifying ways to address it — instead of kicking the can down the road for 18 months,” Bushong said.
Denver Water spokeswoman Stacy Chesney said the utility “anticipates that these activities should help minimize future spikes of molybdenum on Ten Mile Creek.”
Climax Molybdenum officials “are pleased” that the CDPHE granted the extension, Freeport McMoRan spokesman Eric Kinneberg said. “During the time the temporary modification is in place, additional independent analyses of the recently completed studies on molybdenum’s impact on human and animal health will proceed, and we look forward to discussing their conclusions with our stakeholders,” Kinneberg said. “Climax will also evaluate and share information on possible methods to reduce the variation of molybdenum concentrations in the discharge, in addition to continuing its environmental stewardship and robust water treatment.”
The Environmental Protection Agency is required to list unregulated water contaminants and has set health advisory levels for some, including a 40-ppb limit for molybdenum. That means the concentration in drinking water is not expected to harm a person exposed to molybdenum at that level. The EPA hasn’t set a drinking-water regulation for molybdenum.
The Agency for Toxic Substances and Disease Registry, or ATSDR, has determined that ingesting no more than 45 micrograms of molybdenum a day is OK for adults but that most Americans ingest 76 to 109 micrograms. Long-term exposure of rats and mice to molybdenum dust has been shown to cause damage to the nasal cavity and lungs. Animal studies also found molybdenum at high levels can impair reproduction, kidneys and lungs. ATSDR officials have said they’ll produce a toxicology profile for molybdenum. It is not classified as a carcinogen.