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Cemex’s Cement Plant on June 13, 2022, near Lyons. (Hugh Carey, The Colorado Sun)

State air pollution inspectors have fined Cemex’s Boulder County cement factory $357,000 for multiple violations in 2020 and 2021, and are now probing more possible infractions found in a 2022 inspection, according to health department officials and a consent agreement.  

Neighbors emboldened by a surprise forced closure of the raw materials mine that until this year was paired with the cement kiln say they will keep pushing the state, county land use regulators and other agencies to investigate complaints and move toward shutting down the kiln.

Cemex in May signed a consent decree agreeing to pay a fine for the earlier state violations — while not admitting any fault — nearly two years after an Air Pollution Control Division inspector visited the Lyons property and discovered the problems. Cemex was cited for broken filtering equipment failing to capture kiln dust, monitors for pollutants like mercury, sulfur dioxide and nitrogen oxides going offline for long periods, and excess dust plumes. 

State Air Pollution Control Division officials cannot discuss the newer violations currently under investigation, division chief Michael Ogletree said. But those reviews will continue until the state decides on potential sanctions, he said. 

“There were some that were similar to those violations in 2021. But there were also some newer ones as well,” Ogletree said. “We’re pretty close to finalizing that inspection report and then headed towards enforcement.” 

Cemex, as it did during 2022 hearings with Boulder County Commissioners who ultimately rejected a permit extension for the mine near Lyons, emphasized the utility of cement products throughout Colorado and the jobs created by continuing to operate the cement kiln. 

“Given the large positive impact Cemex has had on the area, it is disappointing to see unnecessary efforts to shut the business down,” company spokesperson Maryssa Silva said. “We believe we can continue to be a valuable member of this community. … The consent order reflects the resolution of allegations of past noncompliance. Cemex remains committed to adhering to all local, state and federal requirements for our operations.”

Neighbors to the Boulder County plant said they will continue to raise multiple concurrent complaints with local air pollution, zoning, traffic and mining reclamation officials. 

“We appreciate and applaud the air pollution control division’s engagement with our community regarding the ongoing and increasing public health hazards caused by Cemex Lyons, as well as the recent fine levied for the plant’s infractions in 2021,” said Sarah Lorang, a leader of Good Neighbors of Lyons. “However, it’s often pure coincidence when the community is able to capture evidence of fugitive dust events; those that have been documented are merely the tip of the iceberg.” 

The neighborhood groups and some local officials want the state health department to expand dust monitoring around the clock. They also note the Cemex operating permit adhering to EPA air pollution restrictions, which is issued locally by state health officials, has been expired for 18 months while the company is allowed to operate under the old permit conditions. 

The state’s Ogletree said rewriting the expired permit is underway, and the state looks at multiple factors the neighbors are concerned about. Some of those include Cemex’s location near a town, proximity to lower-income, disproportionately impacted communities and the plant’s presence in one of the counties in the northern Front Range ozone nonattainment area.

Some neighbors and elected officials in Lyons have been organizing against Cemex for years, and in September 2022 won a surprise victory when the Boulder County commissioners declined to renew the company’s permit to operate a cement-making materials mine across Highway 66 from the kiln. Cemex had tried to sweeten a deal for keeping the mine open by offering to close both the mine and the kiln in 15 years, while giving hundreds of acres of recreational open space to the county.

The cement kiln is one of only three in Colorado, and one of the largest greenhouse gas polluters in the state. The high-heat kiln produces a number of toxic local pollutants as well, and neighbors complain operations create clouds of dust. Since the mine closed, Cemex has also sharply increased truck deliveries of material from outside the area, provoking more safety and dust fears. 

Violations from 2020 and 2021 cited in the fine and compliance consent include: 

  • Failure to maintain baghouses, which filter and capture smoke and dust from the kiln, and baghouse emptying in a way that prevents dust contamination of the area. 
  • Downtime for monitoring systems meant to keep track of releases of potentially toxic emissions like mercury. 
  • Failure to monitor pollutants like nitrogen oxide, sulfur dioxide and carbon. 
  • Failure to prevent or control dust plumes. 

Michael Booth is The Sun’s environment writer, and co-author of The Sun’s weekly climate and health newsletter The Temperature. He and John Ingold host the weekly Sun-Up podcast on The Temperature topics every Thursday. He is co-author with...